| By Author | [ A B C D E F G H I J K L M N O P Q R S T U V W X Y Z | Other Symbols ] |
| By Title | [ A B C D E F G H I J K L M N O P Q R S T U V W X Y Z | Other Symbols ] |
| By Language |
|
Download this book: [ ASCII | HTML | PDF ] Look for this book on Amazon Tweet |
Title: Outlines of a Mechanical Theory of Storms - Containing the True Law of Lunar Influence
Author: Bassnett, T.
Language: English
As this book started as an ASCII text book there are no pictures available.
*** Start of this LibraryBlog Digital Book "Outlines of a Mechanical Theory of Storms - Containing the True Law of Lunar Influence" ***
+------------------------------------------------------------------+
| |
| Transcriber's Note |
| |
| Special characters: This UTF-8 text file uses the following |
| special characters: |
| α δ ε η ι λ μ ν ο π ρ ς σ τ φ Ἡ ϛ |
| ☾ ♃ ♄ ♅ ♆ ♈ ⊿ ′ ″ ⅓ œ |
| If these do not display, you may prefer to use the HTML version |
| which provides mouse-hovers for the more unusual characters, or |
| the ISO-8859-1 text which transliterates them. |
| |
| Printer errors: Obvious typographical errors in the original |
| have been corrected in this version, and full details of the |
| corrections can be found in the HTML version of this ebook. |
| However, the inconsistent spelling of Ottawa/Ottowa, and the |
| inconsistent use of comma or full-stop as thousands separators |
| has been left as in the original. The value given for the |
| eccentricity of Uranus may also be a printer error. |
| |
+------------------------------------------------------------------+
OUTLINES
OF
A MECHANICAL THEORY OF STORMS,
CONTAINING
THE TRUE LAW OF LUNAR INFLUENCE,
WITH
PRACTICAL INSTRUCTIONS TO THE NAVIGATOR, TO ENABLE
HIM APPROXIMATELY TO CALCULATE THE COMING
CHANGES OF THE WIND AND WEATHER,
FOR ANY GIVEN DAY, AND FOR
ANY PART OF THE OCEAN.
BY T. BASSNETT.
Ἡ δε μεσοτης εν πασιν ασφαλεϛερα
NEW YORK:
D. APPLETON & COMPANY,
346 & 348 BROADWAY,
AND 16 LITTLE BRITAIN, LONDON.
1854.
Entered, according to Act of Congress, in the year 1853, by
T. BASSNETT,
In the Clerk's Office of the Southern District of New York.
CONTENTS.
SECTION FIRST.
Present State of the Science of Meteorology--Primordial Condition of the
Solar System--Theory of Gravitation the great key of Nature--Bessell's
doubts of its perfect adequacy--the Newtonian Vacuum: its
difficulties--Nature of the element called Ether--The Medium of Space
and the Electric Fluid--Ponderosity of Matter--Dynamical law of
Equilibrium--Specific heat and its relation to space--A Plenum not
opposed to Gravitation--The medium of space in motion--Formation of
Vortices--A new principle developed--Elements of the problem--Hutton's
theory of the production of rain--Indications of change and the
cause--Action of the Ethereal Current--Physical process of Atmospheric
Derangement--Redfield's theory of Storms: its difficulties--All storms
are of brief duration and limited extent. 13
SECTION SECOND.
Mechanical action of the Moon--The Moon's mass--Axis of the Terral
Vortex affected by the Moon: its inclination and position: its
displacement--An example of the principle--Corrections
necessary--Milwaukie storm--New York storm--Ottawa storm--Liverpool
storm--Names and recurring order of the storm-producing agents--Record
of the weather--Second New York storm. 58
SECTION THIRD.
Lunar influence rejected by the learned--Their conclusions not
valid--Modifying causes in accordance with these principles--Years and
seasons vary in character--Superficial temperature of different
Planets--No storms on the planet Mars--Rotation the cause of Ocean and
Atmospheric Currents--Pressure of the atmosphere and its regular and
irregular variations--Terrestrial Magnetism--Internal Constitution of
the Globe--Magnetic variations--Cause of these variations--Magnetic
storms--Aurora Borealis: its altitude--Earthquakes; their possible
connection with Storms. 101
SECTION FOURTH.
The solar spots--Law of periodicity compared with the theory--Existence
of another planet beyond Neptune probable--Masses of the Sun and
Planet yet uncertain--The Law of Gravitation not above
suspicion--Proofs of this--The full of the Moon--Density of the
Ethereal Medium: its law in the Solar Vortex--Bode's law of the
planetary distances--Law of planetary density--Law connecting the
present and former diameters of the planets--Disturbing action of the
Ether--Kepler's third law not rigidly exact--Inconsistencies of
Astronomers--Nature of light and heat--Distinction between light and
heat. 147
SECTION FIFTH.
Comets--Their small inclinations--Their motions chiefly direct--Comet of
1770 and 1844--Cause of acceleration in the case of Encke--Anomalous
motions of the comet of 1843--Change of diameter at different
distances of a comet from the sun--Cause of this change--Nature of the
nebulosity--Formation of the tail--Compound nature of a comet's
light--motion and direction of a comet's tail--Phenomena presented by
the great comet of Halley--Mass of a comet--The Zodial light--Nebulous
stars--Shooting stars--Periodic showers--Periodicity doubtful--Cause
of the apparent periodicity--Cause for being more numerous in Autumn
than in Spring. 187
SECTION SIXTH.
State of the polar ice since 1845--Sir John Franklin's track--Probable
existence of islands north of Behring's Straits--Possibility of
subsisting in the Arctic islands--News from the
Investigator--Necessity of searching in a higher latitude than the
Investigator visited--Franklin's misfortunes due to Scientific
Errors--Relative levels of the Atlantic and Pacific Oceans--The Arctic
seas more accessible in a few years--Conclusion. 233
PREFACE.
On presenting to the public a work of this novel character,
overstepping, as it does, the barriers erected by modern systems to the
further progress of knowledge, a few words of explanation may not be
inappropriate. Early imbued with a desire to understand the _causes_ of
natural phenomena, the author devoured with avidity the interpretations
contained in the elementary works of orthodox science, until reason and
observation rendered him dissatisfied with the repast. To him it
appeared that there was an evident tendency in scholastic instruction,
to make the knowledge of nature inaccessible to the many, that the world
might be made more dependent on the few; while many of the _established
principles_, on which the learned rested, seemed to be at variance with
the simplicity and consistency of truth. Thus situated, he ventured to
think for himself, and looking back on the history of the past, and
finding so many cases in which the philosophy of to-day was supplanted
by a different system on the morrow, he was led to suspect the
possibility of future revolutions, and was thus determined to be no
longer embarrassed by previous systems, nor deterred by opinions
however learned, which conflicted with a rational recognition of the
mechanical nature of all physical phenomena.
The science of meteorology, to which the following pages are devoted,
is, and always has been, a confessedly complex subject; and on this
account, any suggestions and facts which observation gleans,--no matter
how humble the source may be, should not be denied a hearing by those
professedly engaged in the pursuit of truth. Step by step, the author
became more and more confirmed in his doubts of the soundness of many
modern theories; and in 1838 he had attained a position which enabled
him to allege in the public prints of the day, that there did exist
certain erroneous dogmas in the schools, which stood in the way of a
fuller development of the causes of many meteorological phenomena. This
annunciation was made in general terms, and no notice was taken of it.
Subsequently, he forwarded to the British Association of Science, then
convened at Birmingham, a communication of similar tenor; and at a later
date still, a more particular statement of the advantages of his
discoveries to the navigator and agriculturist, was sent to the British
admiralty. The first of these communications was treated with silent
contempt; the last elicited some unimportant reply. In 1844 a memorial
was presented to Congress, accompanied with a certified copy of
_predictions_ of the weather, written several weeks before the event,
and attested in due form by two impartial witnesses; but neither did
this result in any inquiry as to its truth. During the time since
elapsed, he has been engaged in pursuits which prevented him from
pressing the subject elsewhere, until the spring of 1853, he brought
his theory under the notice of the Smithsonian Institution. This led to
a correspondence between himself and the gentlemanly Secretary of the
Institution, whose doubts of the truth of his allegations were expressed
with kindness, and whose courtesy was in strange contrast with the
conduct of others. In the communications which he forwarded to that
Institution, he gave a detailed statement of the difficulties he had met
with, and expressed the hope that an Institution, created for the
purpose of increasing and diffusing knowledge, would feel justified in
lending the influence of its name to facilitate the completion of a
theory which was yet undeniably imperfect. In view of this, a test was
proposed.[1] "Give us, for example, a prediction of the weather for one
month in each season of the year 1854, for the City of Washington." This
test the author refused, for the reason that he did not consider it
necessary to wait so long; but he informed the Secretary of the
Institution, that he would prepare an outline of his theory, which would
enable him to decide upon the merits of the discoveries claimed. This
outline is contained in the following pages. During the summer of 1853
he called upon Professor Henry, then at Chicago, with his manuscript;
but a sudden indisposition prevented that gentleman from having it read.
He, however, strongly recommended its publication from such impressions
he then received.[2] This the author had resolved on, from a sense of
duty to the world at large, although the promise was rather of
prospective loss than of present benefit. The peculiar form under which
the theory appears, is, therefore, a result of the circumstances above
stated, and of the author's present inability to enter into the minute
details of a subject, which embraces in its range the whole visible
creation.
In extending the theory to other phenomena, he has only fearlessly
followed out the same principles which have conducted him to a knowledge
of a disturbing cause, to which atmospheric storms owe their origin, and
in doing so he has conferred with no one. For whatever of merit or of
blame may therefore justly attach to these views, he alone is
responsible. If he has charged the scientific with inconsistency, or
with sometimes forgetting that the truth of their unnecessarily abstruse
investigations depends on the truth of the data, he at least is
conscientious; for he is too well aware that to provoke an unfavorable
verdict by contending against such fearful odds, is not the surest way
to either wealth or fame, or even to an acknowledgment of at least _the
mite_, which he cannot but feel that he has contributed to the treasury
of knowledge. That the scientific organisations of the day do tend to
curb the aberrations of a fanciful philosophy, cannot be denied; but at
the same time there is engendered such a slavish subordination as checks
the originality of thought, and destroys that perfect freedom from the
trammels of system, so necessary to success in the pursuit of truth. Of
such an influence the author explicitly asserts his entire independence.
In thus introducing his theory, the reader is forewarned that he will
not find it dressed in the fascinating garb of the popular literature of
the day, whose chief characteristic is to promise much when possessing
little. It is, however, a plant of the author's own raising, unpropped,
unpruned, with none of the delicate tendrils or graceful festoons of the
trellissed vine; yet he flatters himself that its roots are watered by
the springs of truth, and hopes that he who is in quest of _that_, will
not find, amidst its many clusters, any fruit to set his teeth on
edge.
FOOTNOTES:
[1] Extract from a letter from Professor Henry.
[2] This gentleman kindly offered to contribute from his own private
means, to forward the publication, but he could do nothing officially
without submitting the manuscript to three different censors. He who
claims a new discovery, will seldom be satisfied to have it judged by
men who are engaged in the same investigations, however pure and
honorable they may be. Is this Institution adopting the best plan of
aiding truth, in its struggles against error? Should any man sit as
judge in his own trial? If there had been a powerful Institution to
stand between Galileo and the scientific of his day, his doctrines would
not have been condemned, and the world would have been fifty years more
in advance.
MECHANICAL THEORY OF STORMS.
SECTION FIRST.
PRESENT STATE OF METEOROLOGY.
The present state of the science of which we are about to treat, cannot
be better defined than in the words of the celebrated Humboldt, who has
devoted a long life to the investigation of this department of Physics.
He says: "The processes of the absorption of light, the liberation of
heat, and the variations in the elastic and electric tension, and in the
hygrometric condition of the vast aërial ocean, are all so intimately
connected together, that each individual meteorological process is
modified by the action of all the others. The complicated nature of
these disturbing causes, increases the difficulty of giving a full
explanation of these involved meteorological phenomena; and likewise
limits, or _wholly precludes_ the possibility of that predetermination
of atmospheric changes, which would be so important for horticulture,
agriculture, and navigation, no less than for the comfort and enjoyment
of life. Those who place the value of meteorology in this problematic
species of prediction, rather than in the knowledge of the phenomena
themselves, are firmly convinced that this branch of science, on account
of which so many expeditions to distant mountainous regions have been
undertaken, has not made any very considerable progress for centuries
past. The confidence which they refuse to the physicist they yield to
changes of the moon, and to certain days marked in the calender by the
superstition of a by-gone age."
The charge thus skilfully repelled, contains, however, much truth; there
has been no adequate return of the vast amount of labor and expense thus
far devoted to this branch of knowledge. And it is not wonderful that
the popular mind should expect a result which is so much in accordance
with the wants of mankind. Who is there whose happiness, and health, and
comfort, _and_ safety, and prosperity, may not be more or less affected
by reducing to law, the apparently irregular fluctuations of the
weather, and the predetermination of the storm? To do this would be the
crowning triumph of the age; and the present theory has pioneered the
way for its speedy accomplishment.
ORIGINAL CONDITION OF THE EARTH.
That the present order of things had a beginning, is taught by every
analogy around us, and as we have the glaring fact forced upon us, that
our globe has experienced a far higher temperature on its surface than
obtains at present, and moreover, as it is demonstrated beyond a cavil,
that the interior is now of far higher temperature than is due to solar
radiation, we are justified in concluding, not only that the condition
of the interior of our globe is that of fusion, but that its original
temperature was far higher than at present; so that the inference is
allowable that there has been a time when the whole globe was _perhaps_
in this state. But why should we stop here? There are three states of
matter, the solid, the fluid, and the gaseous; and with this passing
glance at the question, we will jump at once to the theory of La
Place,--that not only our own globe, but the whole solar system, has
been once in the nebulous state.
In justice to himself, the author ought to remark, that he had reasoned
his way up to this starting point, before even the name of La Place had
reached his ears. He makes the remark in order to disclaim any desire to
appropriate that which belongs to another; as he may innocently speak of
things hereafter, the idea of which has occurred to others. It is not
his intention here to say a word _pro_ or _con_ on the nebular
hypothesis; it is sufficient to allude to the facts, that the direction
of rotation and of revolution is the same for all the planets and
satellites of our system; and that the planes on which these motions are
performed, are nearly coincident. That this concordance is due to one
common cause, no one acquainted with the theory of probabilities will
pretend to deny.
GREAT OBJECT OF LA PLACE.
The science of Astronomy occupies a pre-eminent rank in the physical
circle, not only on account of that dignity conferred upon it in the
most remote antiquity, or as being the grand starting point--the
earliest born of science--from whence we must contemplate the visible
creation, if we would reduce its numerous details into one harmonious
whole; but also on account of its practical fruits, of the value of
which modern commerce is an instance. Accordingly we will glance at its
past history. In the earliest ages there was no doubt a rational view
entertained of the movements of the planets in space. From the Chaldeans
to the Arabs, a belief prevailed, that space was filled with a pure
ethereal fluid, whose existence probably did not rest on any more solid
foundation than analogy or tradition. One hundred years after Copernicus
had given to the world the true arrangements of our planetary system,
Descartes advanced his theory of vortices in the ethereal medium, in
which the planets were borne in orbits around the sun, and the
satellites around their primaries. This idea retained its ground with
various additions, until the Geometry of Newton reconciled the laws of
Kepler with the existence of a power pertaining to matter, varying
inversely as the squares of the distances, to which power he showed the
weight of terrestrial bodies was owing, and also the revolution of
the moon about the earth. Since Newton's day, those deviations from the
strict wording of Kepler's laws, have been referred to the same law,
and the avowed object of the author of the "Mechanique Celeste," was to
bring all the great phenomena of nature within the grasp of analysis, by
referring them to one single principle, and one simple law. And in his
Introduction to the Theory of the Moon, he remarks: "Hence it
incontestibly follows, that the law of gravitation is the sole cause of
the lunar inequalities."
BESSEL'S OPINION.
However beautiful the conception, it must be admitted that in its _à
priori_ aspect, it was not in accordance with human experience and
analogy to anticipate a successful issue. In nature law re-acts upon
law, and change induces change, through an almost endless chain of
consequences; and it might be asked, why a simple law of matter should
thus be exempt from the common lot? Why, in a word, there should be no
intrinsic difference in matter, by which the gravitation of similar or
dissimilar substances should be affected? But experiment has detected no
such differences; a globe of lead and a globe of wood, of equal weight,
attract contiguous bodies with equal force. It is evident, therefore,
that if there be such differences, human means are not yet refined
enough to detect them. Was the issue successful then? Generally
speaking, we may say yes. But where there is a discrepancy between
theory and observation, however small that may be, it shows there is
still something wanting; and a high authority (Professor Bessel) says in
relation to this: "But I think that the certainty that the theory based
upon this law, _perfectly_ explains all the observations, is not
correctly inferred." We will not here enumerate the cases to which
suspicion might be directed, neither will we more than just allude to
the fact, that the Theory of Newton requires a vacuum, in order that the
planetary motions may be mathematically exact, and permanent in their
stability.
A VACUUM REQUIRED BY MODERN SYSTEMS.
Whatever may be the practical belief of the learned, their fundamental
principles forbid the avowal of a plenum, although the undulatory theory
of light renders a plenum necessary, and is so far virtually recognized
by them, and a correction for resistance is applied to the Comet of
Encke. Yet there has been no attempt made to reconcile these opposing
principles, other than by supposing that the celestial regions are
filled with an extremely rare and elastic fluid. That no definite view
has been agreed on, is not denied, and Sir John Herschel speculates on
the reality of a resisting medium, by suggesting questions that will
ultimately have to be considered, as: "What is the law of density of the
resisting medium which _surrounds_ the sun? Is it in rest or in motion?
If the latter, in what direction does it move?" In these queries he
still clings to the idea of Encke, that the resistance is confined to
the neighborhood of the sun and planets, like a ponderable fluid. But
the most profound analyst the world has ever boasted, speaks less
cautiously, (Poisson Rech.) "It is difficult to attribute, as is usually
done, the incandescence of aërolites to friction against the molecules
of the atmosphere, at an elevation above the earth where the density of
the air is almost null. May we not suppose that the electric fluid, in a
neutral condition, forms a kind of atmosphere, extending far beyond the
mass of our atmosphere, yet _subject to terrestrial attraction_, yet
_physically imponderable_, and, consequently, following our globe in its
motion?" The incandescence of aërolites must, therefore, be owing to
friction against the molecules of the electric fluid which forms an
atmosphere around the globe. According to this view, some force keeps it
there, yet it is not ponderable. As it is of limited extent, this is not
the medium whose undulations brings to light the existence of the stars;
neither is Encke's, nor Herschel's, nor any other resisting medium.
Where shall we find the present established principles of science? If we
grant the Newtonians a plenum, they still cling to attraction of _all
matter_ in some shape. If we confine them to a vacuum, they will
virtually deny it. Is not this solemn trifling? How much more noble
would it be to exhibit a little more tolerance, seeing that they
themselves know not what to believe? We do not offer these remarks as
argument, but merely as indications of that course of reasoning by which
we conclude that the upholders of the present systems of science are not
entitled to any other ground than the pure Newtonian basis of an
interplanetary vacuum.
DIFFICULTIES OF THIS VIEW.
This, then, is the state of the case: Matter attracts matter directly as
the mass, and inversely as the squares of the distances. This law is
derived from the planetary motions; space is, consequently, a void; and,
therefore, the power which gives mechanical momentum to matter, is
transferred from one end of creation to the other, without any physical
medium to convey the impulse. At the present day the doctrines of
Descartes are considered absurd; yet here is an absurdity of a far
deeper dye, without we resort to the miraculous, which at once
obliterates the connection between cause and effect, which it is the
peculiar province of physical science to develop. Let us take another
view. The present doctrine of light teaches that light is an undulation
of an elastic medium necessarily filling all space; and this branch of
science probably rests on higher and surer grounds than any other. Every
test applied to it by the refinements of modern skill, strengthens its
claims. Here then the Newtonian vacuum is no longer a void. If we get
over this difficulty, by attributing to this medium a degree of tenuity
almost spiritual, we shall run upon Scylla while endeavoring to shun
Charybdis. Light and heat come bound together from the sun, by the same
path, and with the same velocity. Heat is therefore due also to an
excitement of this attenuated medium. Yet this heat puts our atmosphere
in motion, impels onward the waves of the sea, wafts our ships to
distant climes, grinds our corn, and in various ways does the work of
man. If we expose a mass of metal to the sun's rays for a single hour
the temperature will be raised. To do the same by an artificial fire,
would consume fuel, and this fuel would generate the strength or force
of a horse. Estimate, therefore, the amount of force received from the
sun in a single day for the whole globe, and we shall find that nothing
but a material medium will suffice to convey this force.
Let us appeal to analogy. The undulations of our atmosphere produce
sound; that is, convey to the ear a part of a mechanical force imparted
to a solid body--a bell for instance. Let us suppose this force to equal
one pound. On account of the elasticity of the bell, the whole of the
force is not instantaneously imparted to the surrounding air; but the
denser the air the sooner it loses its motion. In a dense fluid like
water, the motion is imparted quickly, and the sound is not a ring but a
click. If we diminish the density of the air, the loss of motion is
retarded; so that we might conceive it possible, provided the bell could
be suspended in a _perfect vacuum_, without a mechanical tie, and there
was no friction to overcome from the rigidity of its particles, that the
bell would vibrate forever, although its sound could never reach the
ear. We see, therefore, that the mechanical effect in a given time, is
owing to the density of the medium. But can we resort to such an
analogy? Every discovery in the science confirms more and more the
analogy between the motions of air and the medium of space; the angle of
reflexion and incidence follows the same law in both; the law of
radiation and interference; and if experiments were instituted, there
can be but little doubt that sound has also got its spectrum.
ETHER IMPONDERABLE.
The medium of space, therefore, is capable of conveying a mechanical
force from one body to another; it therefore possesses inertia. Does it
also possess gravity? If we forsake not the principles of science, it is
but right that we expect science shall abide by her own principles.
Condensation in every elastic medium is as the compressing power,
according to all experiments. In the case of our atmosphere under the
law of gravitation, the density of air, (supposing it to be infinitely
expansible,) at a height only of ten semidiameters of the earth above
its surface, would have only a density equal to the density of one cubic
inch of such air we breathe, if that cubic inch was to be expanded so as
to fill a globular space whose centre should be the earth, and whose
surface should take inside the whole visible creation. Such a medium
could convey no mechanical force from the sun, and therefore the medium
of space cannot be ponderable. Simple as the argument is, it is
unassailable.
ELECTRIC FLUID THE MEDIUM OF SPACE.
Let us take yet another view. All experiments prove that the phenomenon
we call electricity, is owing to a disturbance of the equilibrium or
natural condition of a highly elastic fluid. In certain conditions of
the atmosphere, this fluid is accumulated in the region of the clouds,
and by its tension is enabled to force a passage through opposing
obstacles, in order to restore the equilibrium. By experiment it is
found that dry dense air opposes the greatest obstacle to its escape. As
the air is rarefied, this obstacle diminishes; until in a vacuum the
transmission may be considered instantaneous. There ought to be,
therefore, a greater escape of electricity from the clouds upwards than
downwards; and, if space be void, or only filled with an extremely
attenuated matter, the electricity of the earth, considered as an
elastic fluid without ponderosity, (and no law of condensation from the
law of gravity in harmony with its other attributes, will allow us to
consider it otherwise,) _would long since have left the earth_. The same
objection applies in the case of the galvanic and magnetic fluids. If we
entertain the idea that electricity is a mere disturbance of natural
condition, wherein two fluids are united, and that an excess of one is
necessarily attended by deficiency in the other, we depart from the
first rule of philosophy, which teaches us to admit no greater number of
causes than are sufficient to explain the phenomenon. For we fearlessly
assert that not a single fact exists in electrical science, which can be
explained better on Dufoy's theory than on Franklin's; and the former
objections would still apply.
NEWTONIAN GRAVITY.
But what is gravity? According to Newton: "Hæc est qualitas omnium in
quibus experimenta instituere licet, et propterea per Reg. 3 de
universes affirmanda est." _Vide_ Prin. Lib. Ter. Cor. 2. Prop. vi.
Now the other primary qualities of matter are unaffected by
circumstances. The inertia of a particle of matter is the same at
Jupiter as on the earth, so also is its extension; but not so with
gravity. It depends on other matter, and on its distance from it; and
may be less or greater at different times, and in different places. It
is, therefore, not philosophical to say that all matter is necessarily
ponderous, inasmuch as it is a virtue not residing in itself alone, but
needs the existence of other matter to call it into action. If an atom
were isolated in space it would have no weight. If influenced by other
matter, there must be some physical medium to convey the influence, or
gravity is not in accordance with the laws of force and motion. Which
horn of the dilemma shall we take? Let us first admit that there is a
principle of gravitation, affecting all planetary or atomic matter, and
that there exists a highly elastic medium, pervading all space,
conveying to us the light of the most distant stars, and that this
medium is not affected by gravity. In this summary way, therefore, we
have arrived at the pivot on which this theory turns.
The prominent feature of the theory, therefore, is the necessity it will
show for the existence of an all-pervading medium, and that it possesses
inertia without ponderosity. That electricity is nothing more than the
effects of the condensation and rarefaction of this medium by force.
That it also pervades all atomic matter, whose motions necessarily move
the medium; and, consequently, that there can be no motion without some
degree of electricity. That no change can take place in bodies either by
chemical decomposition, by increase or decrease of temperature, by
friction or contact, without in some measure exciting electricity or
motion of the ether. That galvanism and magnetism are but ethereal
currents without condensation, induced by peculiar superficial and
internal molecular arrangement of the particles of certain substances.
That light and heat are effects of the vibrations of atoms, propagated
through this universal medium from body to body. That the atomic motion
of heat can be produced by the motion of translation or momentum of
bodies in the gross, that is, by friction, by compression, &c.; and can
be reconverted into momentum at our pleasure. Hence the latent heat or
specific atomic motion of combustibles, originally derived from the sun,
is transferred to atoms, which are capable of being inclosed in
cylinders, so as to make use of their force of expansion, which is thus
converted into momentum available for all the wants of man.
GRAVITY MECHANICAL.
When we come to a full examination of this theory, we shall further
reason that this _ether_ so far from being of that quasi spiritual
nature which astronomers would have us believe, is a fearfully energetic
fluid, possessing considerable inertia and elasticity; that its law of
condensation is that of all other fluids, that is, as the compressing
force directly; and that its effects are simply a product of matter and
motion. We will next endeavor to prove that the gravity of planetary
matter could not exist without this ethereal medium, by showing that it
is an effect produced by the interference of _opposing waves_, whereby a
body is prevented from radiating into space its own atomic motion, from
the side opposite which another body is placed, as much as on the
opposite side, and consequently it is propelled by its own motion
towards the other body. And this effect following the simple law of
inertia and radiation, is directly as the mass, and inversely as the
squares of the distances.
GREAT PRINCIPLE OF DYNAMICS.
One great principle to be kept in view in this investigation, is that
which teaches that the product of matter, angular velocity, and distance
from the centre of motion, must ever be a constant quality in every
balanced system. Yet this principle does not seem to be observed in the
case of the planets. We will, however, endeavor to show that it is
rigidly observed. And we will extend the principle further, and contend
that all the phenomena of nature are consequences of the constant
tendency of matter to conform to this principle of equilibrium, when
suffering temporary derangement from the operation of other laws. That
throughout the system of nature, equal spaces possess equal force. That
what we call temperature, is nothing more than the motion of equilibrium
or atomic momentum of space; or, in other words, that if all space were
fluid, and in a state of equilibrium, the product of each atom of equal
volume, by its motion would be a constant quality. From this it would
seem to follow, that the specific heat of bodies should be inversely as
their atomic weights; and this does, no doubt, _approximately_ obtain as
was proved by Dulong and Petit, for metallic substances, more recently
by Regnault, and has since been extended by Garnier to other substances.
But it is to the gaseous state that we must look for confirmation of the
principle that equal spaces possess equal power; and in doing so, it
will be necessary to bear in mind, that the ether also is affected by
temperature.
SPECIFIC HEAT.
It has been contended by some that the medium which conveys the
impression of light through transparent, bodies, is necessarily more
dense within the body than without; but according to this theory the
converse is true. A ray of light is a mechanical impulse, propagated
through an elastic medium, and, like a wave in water, tends to the side
of least resistance. Within a refracting body the ether is rarefied, not
only by the proximity of the atoms of the body (or its density), but
also by the motions of those atoms; so that if two _simple_ gases of
different specific gravity be made equal in density by compression,
their refraction will be approximately as their specific heats. In the
case of solids and liquids, or even compound gases, there is a continual
absorption of motion to produce the cohesion of composition and
aggregation. And the specific heats of compound gases will be found
greater than those of simple gases, in proportion to the loss of volume
by combination, _ceteris paribus_. If impenetrability be a law of
matter, the more a portion of atomic matter is condensed, the less ether
will be found in the same space. The same is also true when the natural
density or specific gravity of a gas is greater than that of another.
And the lighter the gas, the more will this circumstance vitiate the
experiments to determine its specific heat. There is, therefore, this
great source of fallacy in such experiments, viz.: that the ether
permeates all fluids and solids, and that _its specific heat probably
far exceeds that of all other matter_. This is a fundamental position of
the theory, in support of which we will introduce a fact announced by
M. V. Regnault, which was published in the Comptes Rendus of the French
Academy for April, 1853. He says: "In the course of my researches I have
encountered, indeed, at every step, anomalies which appeared to me
inexplicable, in accordance with the theories formally recognized. For
the sake of illustration I will quote one instance: 1st, a mass of gas,
under a pressure of ten atmospheres, is contained in a space which is
suddenly doubled; the pressure falls to five atmospheres. 2d. Two
reservoirs of equal capacity are placed in a calorimeter; the one is
filled with a gas, under a pressure of ten atmospheres; the second is
perfectly empty. In these two experiments, the initial and final
conditions of the gas are the same; but this identity of condition is
accompanied by calorific results which are very different; for while in
the former experiment there is a reduction of temperature, in the second
the calorimeter does not indicate the slightest alteration of
temperature." This experiment tends to confirm the theory. In the first
experiment, the sudden doubling of the space causes the ether also to
expand, inasmuch as the sides of the vessel prevent the instantaneous
passage of the external ether. In the second, both vessels are full, one
of ether, and the other of air mixed with ether; so that there is no
actual expansion of the space, and consequently no derangement of the
quantity of motion in that space.
LAW OF SPECIFIC HEAT.
From this view it is evident that the specific heat of elastic fluids
can only be considered as approximately determined. If equal spaces
possess equal momenta, and the ethereal or _tomic_ matter be inversely
as the weight of the atomic matter in the same space, it follows that
the product of the specific gravities and specific heats of the simple
gases should be constant; or that the specific heats should be inversely
as the specific gravities,--taking pound for pound in determining those
specific heats. If we test the matter by the data now afforded, it is
best to obey the injunction, "_In medio tutissimus ibis_." In the
following table, the first column are the values obtained by Regnault;
in the second, the former values; and in the third, the mean of the two.
Gases. Reg. specific heats. Former specific heats. Mean.
Atmospheric air, .237 .267 .252
Oxygen, .218 .236 .227
Nitrogen, .244 .275 .260
Hydrogen, 3.405 3.294 3.350
The specific gravities of these gases, according to the best tables in
our possession, are:
Specific gravities. Mean. Products.
Atmospheric air, 1.0000 × .252 = .252
Oxygen, 1.1111 × .227 = .252
Nitrogen, 0.9722 × .260 = .252
Hydrogen, 0.0745 × 3.350 = .249
As might be expected, there is a greater discrepancy in the case of
hydrogen.
If we test the principle by the vapor of water, we must consider that it
is composed of two volumes of hydrogen and one volume of oxygen, and
that one volume disappears; or that one-third of the whole atomic
motion is consumed by the interference of the vibrations of the ether,
necessary to unite the atoms, and form an atom of water. We must
therefore form this product from its specific gravity and two-thirds of
its specific heat. On no one subject in chemistry has there been so much
labor expended, as in determining the specific heat of watery vapor. In
relation to this, Regnault observes: "It is important to remark that an
immense number of experiments have been made, to find the specific heat
of steam, and that it is about one-half of what it was thought to be."
He gives its value .475; but this is vitiated still, by the
non-recognition of the specific heat of the ether. Former experiments
give .847. Perhaps Regnault's numbers are entitled to the most weight.
Instead of taking the mean, therefore, we will give double weight to his
results; so that we get .600 for the specific heat of vapor, and as its
specific gravity is .625, the product .400 × .625 is .250, the same as
for hydrogen. Little importance, however, should be attached to such
coincidences, owing to the uncertainty of the numbers. If our position
be correct, the specific heat of hydrogen should be 10 times greater
than of oxygen. The atomic weights are as 1 to 8, while their volumes
are as 2 to 1; therefore, for equal spaces, the matter is as 1 to 16.
Calling the specific heat 10 to 1, and taking the amount due to half the
space, the product becomes as 8 to 16; but in the rarer gas there is
_8 times_ as much ethereal momentum or matter, which, added to the
atomic matter, renders the spaces equal.[3] Regnault's results give a
ratio of specific heats = 1 to 3.405/.215 = 1 to 15.6.
THE GOLDEN MEAN.
The history of science proves how few have practically respected the
adage of the ancients, which we have chosen for our motto; words which
ought to be written in letters of gold in every language under the sun.
Descartes, by considering the mechanical impulse of the ether sufficient
to explain the planetary motions, failed to detect the force of gravity
in the heavens. Newton, on the other hand, feeling that his law was
sufficient to explain them, and requiring a vacuum for its mathematical
accuracy, rejected the notion of an ethereal medium. His successors,
following too closely in his footsteps, and forgetting the golden law,
have forced themselves into a position by no means enviable. The
short-period comet has driven them to a resisting medium, which, while
according to Encke's hypothesis of increasing density around the sun, it
explains the anomalies of one periodical comet, requires a different
law of density for another, and a negative resistance for a third.
OUTLINES OF THE PROBLEM.
From the position we now occupy, we can see the outlines of the problem
before us, viz.: To reconcile the existence of an ethereal medium with
the law of gravitation, and to show the harmony between them. We shall
thus occupy the middle ground, and endeavor to be just to the genius of
Descartes, without detracting from the glory of Newton, by demonstrating
the reality of the Cartesian vortices, and by showing that the ether is
not affected by gravitation, but on the other hand is _least dense_ in
the centre of our system. But what (it may be asked) has this to do with
the theory of storms? Much every way. And we may so far anticipate our
subject as to _assert_ that every phenomenon in meteorology where force
is concerned, is dependent on the motions of the great sea of electric
fluid which surrounds us, in connection with its great specific,
caloric. If we are chargeable with overweening pretensions, let it be
attributed to the fact that for the last fifteen years we have treated
the weather as an astronomical phenomenon, calculated by simple formulæ,
and that the evidence of its truth has been almost daily presented to
us, so as to render it by this time one of the most familiar and
palpable of all the great fundamental laws of nature. True, we have
neither had means nor leisure to render the theory as perfect as we
might have done, the reason of which we have already communicated.
MOTIONS OF THE STARS.
In investigating the question now before us, we shall first take the
case of an ethereal vortex without any reference to the ponderable
bodies which it contains, considering the ether to possess only inertia.
If there be a vortex around the sun, it is of finite extent; for if the
ether be co-extensive with space, and the stars likewise suns with
surrounding vortices, the solar vortex cannot be infinite. That there is
an activity in the heavens which the mere law of attraction is
incompetent to account for, is an admitted fact. The proper motions of
the fixed stars have occupied the attention of the greatest names in
astronomy, and motions have been detected, which according to the theory
of gravity, requires the admission of invisible masses of matter in
their neighborhood, compared with which the stars themselves are
insignificant. But this is not the only difficulty. No law of
arrangement in the stars can exist that will save the Stellar system
from ultimate destruction. The case assumed by Sir John Herschel, of a
cluster, wherein the periods shall be equal, cannot be made to fulfil
the conditions of being very numerous, without infringing the other
condition--the non-intersection of their orbits; while the outside stars
would have to obey another law of gravitation, and consequently would be
still more liable to derangement from their ever-changing distances
from each other, and from those next outside; in brief, the stability of
those stars composing the cluster would necessarily depend on the
existence of outside stars, and plenty of them. But those outside stars
would follow the common law of gravity, and must ultimately bring ruin
on the whole. We know such clusters do exist in the heavens, and that
the law of gravity alone must bring destruction upon them. This is a
case wherein modern science has been instrumental in drawing a veil over
the fair proportions of nature. That such collections of stars are not
designed thus to derange the order of nature, proves _à priori_, that
some other conservative principle must exist; that the medium of space
must contain many vortices--eddies, as it were, in the great ethereal
ocean, whose currents are sweeping along the whole body of stars. We
shall consider, (as a faint shadowing of the glorious empire of
Omnipotence,) that the whole infinite extent of space is full of motion
and power to its farthest verge; and it may be an allowable stretch of
the imagination to conceive that the whole comprises one infinite
cylindrical vortex, whose axis is the only thing in the universe in a
state of absolute unchangeableness.
VORTICOSE MOTION.
Let us for a moment admit the idea of an infinite ocean of fluid matter,
having inertia without gravity, and rotating around an infinite axis, in
this case there is nothing to counteract the effect of the centrifugal
force. The elasticity of the medium would only oppose resistance in a
vortex of finite diameter. Where it is infinite, each cylindrical layer
is urged outward by its own motion, and impelled also by those behind.
The result would be that all the fluid would at last have left the axis,
around which would exist an absolute and eternal void; into which
neither sound, nor light, nor aught material, could enter. The case of
a finite vortex is very different. However great the velocity of
rotation, and the tendency of the central parts to recede from the axis,
there would be an inward current down either pole, and meeting at the
equatorial plane to be thence deflected in radii. But this radiation
would be general from every part of the axis, and would be kept up as
long as the rotation continued, if the polar currents can supply the
drain of the radial stream, that is, if the axis of the vortex is not
too long for the velocity of rotation and the elasticity of the ether,
there will be no derangement of the density, only a tendency. And in
this case the periodic times of the parts of the vortex will be directly
as the distances from the axis, and the absolute velocities will be
equal.
FORMATION OF VORTICES.
There is reason to suspect that Newton looked at this question with a
jaundiced eye. To do it justice, we must consider the planetary matter
in a vortex, as the exponent of its motion, and not as originating or
directing it. If planetary matter becomes involved in any vortex, it
introduces the law of gravitation, which counteracts the expulsive force
of the radial stream, and is thus enabled to retain its position in the
centre. A predominating mass in the centre will, by its influence,
retain other masses of matter at a distance from the centre, even when
exposed to the full power of the radial stream. If the power of the
central mass is harmoniously adjusted to the rotation of the vortex,
(and the co-existence of the phenomena is itself the proof that such an
adjustment does obtain,) the two principles will not clash or interfere
with each other. Or in other words, that whatever might have been the
initial condition of the solar vortex, the ultimate condition was
necessarily one of equilibrium, or the system of the planets would not
now exist. With this view of its constitution, we must consider that the
periodic times of the planets approximately correspond to the times of
the contiguous parts of the vortex. Consequently, in the solar vortex,
the density of the ether is directly as the square roots of the
distances from the axis. This is not the place fully to enter into a
discussion of the question, or to show that the position of each planet
in the system is due to the outstanding, uncompensated, portion of the
expulsive force of the radial stream, modified by the density of the
ether within the planets, and also by their own densities, diameters,
inclinations of axis, and periods of rotation. That Jupiter could not
remain in the orbit of Mercury, nor Mercury in that of Jupiter, by
merely exchanging periods and distances, but that each planet can only
be in equilibrio in its own orbit. That any change in the eccentricities
of the planetary orbits will neither increase nor diminish the action of
the radial stream of the vortex, and consequently will not interfere
with the law of gravitation. In relation to the numerous questions that
will spring up from such a position, it is sufficient here to say, that
it is believed all objections can be satisfactorily answered; while, by
this light, a long range of phenomena that have hitherto baffled the
sagacity of the wise, come out plainly, and discover their parentage.
In cometary astronomy we shall find much to substantiate these views.
The anomalies in their motions, the discrepancies in their periods,
calculated from different sets of observations, their nebulosities and
appendages, will all receive a satisfactory solution; and these lawless
wanderers of the deep be placed in a more interesting light.
TEST OF A THEORY.
It has been remarked that the best evidence of the truth of a theory, is
its ability to refer to some general principle, the greatest number of
relevant phenomena, that, like the component masses of the chiselled
arch, they may mutually bind and strengthen each other. This we claim
to be the characteristic of this theory. At the outset it was not
intended to allude to more than was actually necessary to give an
outline of the theory, and to introduce the main question, yet
untouched. We have exhibited the stones of which the arch is composed;
but they may be pasteboard,--for the reader has not handled them. We
will now produce the keystone, and put it in its place. This he shall
handle and weigh. He will find it hard,--a block of granite, cut from
the quarry of observed facts, and far too heavy to be held in its place
by a mere pasteboard structure.
ENUNCIATION OF THE THEORY.
Quitting, therefore, the region of the planets, we will come down to the
surface of our own globe, to seek for some more palpable evidence of the
truth of the following propositions:
1st. That space is filled with an elastic fluid, possessing inertia
without weight.
2d. That the parts of this fluid in the solar system circulate, after
the manner of a vortex, with a direct motion.
3d. That there are also secondary vortices, in which the planets are
placed.
4th. That the earth is also placed in a vortex of the ethereal medium.
5th. That the satellites are passively carried around their primaries,
with the ethereal current, and have no rotation relative to the ether,
and therefore they always present the same face to their primaries, and
have no vortex.
The consideration of these propositions involves many others, many
difficulties, many apparent anomalies and contradictions, which should
bespeak for such a theory,--the offspring of observation, without the
aid afforded by the knowledge of others, and of toil without leisure,--a
large share of indulgence. With this we will close these preliminary
remarks, and present our theory of the physical cause which disturbs
the equilibrium of our atmosphere, and which appears the principal agent
in the production of storms, in the following words:
The dynamical axis of the terral vortex passes through the centre of
gravity of the earth and moon, and is continually circulating over the
earth's surface in both hemispheres, in a spiral,--its latitude and
longitude, at any particular time, being dependent,--
1st. On the relative mass of the moon.
2d. On the inclination of the axis of the vortex to the earth's axis.
3d. On the longitude of the ascending node of the vortex on the lunar
orbit.
4th. On the longitude of the ascending node of the lunar orbit on the
ecliptic.
5th. On the eccentricity of the lunar orbit at the time.
6th. On the longitude of the perigee of the lunar orbit at the time.
7th. On the moon's true anomaly at the time.
MASS OF THE MOON.
Those elements which represent the moon's distance and motion are
accurately known, and may be taken from the Nautical Almanac, being all
embodied in the moon's parallax or semi-diameter, and in the declination
and right ascension; but for the most important element,--the moon's
mass, we in vain look to astronomy. In fact, it may be averred that the
importance attached to astronomical authority, concerning the mass of
the moon, has caused more trouble than any other question of the whole
theory, until we trusted implicitly to the theory itself to determine
it. The determination of three unknown elements, viz.: the moon's mass,
the inclination of the axis of the vortex, and the right ascension of
that axis, is a more difficult problem than at first sight appears,
owing to the nature of the phenomena, which affords the only clue for
its solution. There are six principal vortices ever in operation on the
surface of the earth, and their disturbing influence extends from 200 to
400 miles. To find the precise centre, by one observer confined to one
place, is difficult; and to separate them, so as to be fully assured
that you have the right one, is perhaps still more so. Happily this
tedious labor is accomplished, and we are able with confidence to give
the following important elements, as very close approximations to the
truth:
Mass of the moon 1/72.3
Obliquity of the axis of the vortex 15° to 32° variable.
Right ascension of ditto 250° to 290° variable.
It must be borne in mind that we are now discussing the main or central
vortex of the earth; but before applying them to the calculation, we
will explain the _modus operandi_, waiving for the present the
consideration of the law of density in the Terral vortex. It is evident
at first sight that if the periodic times of the parts of the vortex
contiguous to the moon, are equal to the moon's period approximately,
that the velocity of the ether is greater at the surface of the earth
than the velocity of that surface. Now, we have before argued that the
ether possesses inertia, it therefore would under such circumstances
exert some mechanical action. Consequently, the aërial envelope of our
globe, or its superior stratum, is impelled eastward by _convection_[4]
of the more rapidly rotating ether. And from the extreme tenuity of its
upper layers, is probably forced into immense waves, which will observe
to a certain degree, a general parallelism north and south.
ATMOSPHERIC CURRENTS.
It is a well-known fact, that the prevailing current of the atmosphere
in high latitudes is from the westward. The cause of this is ascribed by
Professor Dove to the transfer of the equatorial portions to a higher
latitude, by which the excess of its rotative velocity is made apparent,
by outstripping the slower moving surface in its progress eastward. No
doubt some effect is due to this, but still a difficulty remains. Let us
follow this current. The polar current reaches the surface on the
borders of the trades with less rotative velocity than the surface, and
is, therefore, met by the surface as a current partaking of both
motions. In the northern hemisphere it is north-east deflected to east
as it approaches the southern trades. By the same reasoning, coming from
the north before it readies the surface, it ought to be also a
north-east wind above the lower westerly currents. Now it is an observed
fact, that while in the latitude of New York, for instance, the lower
westerly winds are to the easterly, as 3 or 4 to 1, in the highest
regions of observed clouds, the ratio is much increased; and according
to our own observations in this place,[5] we have never seen the highest
cirrus clouds moving westward. How then is this continual interchange
kept up? Assuredly we cannot have a current from the poles without a
contrary current to the poles. If we go into the arctic circle, we again
find the westerly and northerly winds predominating. If the current from
the equator follows the surface, the westerly winds ought to be
south-west. If it be above the surface wind, then the surface wind is
the polar current, and ought to be north-east. Whereas, from the
testimony of all who have visited these regions, the prevailing winds
are north-west. How can this be?
Again, it is proved that the upper current near the equator is also from
the westward--as near due west as possible. Take the latitude of St
Vincent. The difference between the cosine of 13° and radius applied
to the circumference, is about 600 miles, which would give 25 miles per
hour to the eastward, in lat. 13°. But to do this, it is necessary to
transfer it suddenly from the equator; for by a slow motion the easterly
tendency would be lost. Give it 24 hours from the equator to lat. 13°,
without any loss of easterly tendency, and it comes to that latitude
with a velocity of 38 miles per hour to the northward, and only 25 to
the eastward; we have, therefore, a wind from south-west by south. Yet
it is known that in the tropics the highest visible clouds move from the
westward. But as no such case could occur as a transfer in twenty-four
hours without loss, and if we diminish the time, the wind is still more
southerly. Meteorologists usually cite the falling of ashes at Jamaica
during the eruption of Coseguina, in Guatamala, in February 1835, as
coming from south-west, whereas the true direction was about west
south-west, and the trade wind below was about north. But do we deny
that there is an interchange between the frigid and torrid zones? By no
means; but we would show that the great controlling power is external to
our atmosphere, and that the relative velocities of the earth and the
atmosphere is not alone adequate to account for it. By this view the
polar current is a north-west wind (which is impossible by Professor
Dove's theory), or is carried eastward by electric convection.
HUTTON'S THEORY.
Whether we adopt the views of Fourier or Poullet, as to the temperature
of the planetary spaces, it is certain that it is at least equal to, or
less than, the lowest temperature of our globe. It is also a well-known
fact, that the capacity of air to hold vapor in solution, increases in a
higher ratio than the temperature, so that the intermingling of
saturated portions of air, at different temperatures, must _necessarily_
be attended by precipitation of moisture. This idea was advanced by
Doctor Hutton, and considered competent to account for the prominent
meteorological phenomena, until Professor Espy broached a questionable
principle, (and which is rendered still more so by the late
investigations of Regnault,) in opposition to Hutton's theory. That the
theory is deficient, no one can gainsay. That Espy has rendered the
question clearer, is equally hazardous to assert. Hutton failed in
showing a cause for such intermingling on a sufficient scale; while
Espy, it may be suspected, has misinterpreted facts, and incautiously
rejected the only element possessing the power of raising the storm.
GREAT SPECIFIC HEAT OF THE ETHER.
Whatever may be the degree of condensation or rarefaction in the terral
vortex, there must necessarily be a current down the pole or axis,
thence to be deflected along the equatorial plane of the vortex, and
this drain will be as perpetual as the rarefaction of the centre,
(caused by the centrifugal force of rotation,) which calls it forth. It
will now be perceived that the fluid of the vortex, which we shall still
term ether, is neither more nor less than the electric fluid,--the
mighty energising principle of space,--the source of motion,--the cause
of magnetism, galvanism, light, heat, gravity, of the aurora, the
lightning, the zodiacal light, of the tails and nebulosities of comets,
of the great currents of our atmosphere, of the samiel, the hurricane,
and the earthquake. It will be perceived that we treat it as any other
fluid, in relation to its law of motion and condensation. But we have no
right to base our calculations on its resistance, by the analogies
presented by ponderable or atomic matter. Atomic fluids,--even pure air,
may be considered viscid and tenacious when compared to an infinitely
divisible fluid, between whose particles (if we may use the term) no
_attraction_ of any kind exists. No ponderable matter can come in close
contact without feeling the influence of the gravitating force which, at
insensible distances,--such as the breadth of a wave of ether, is
increased in power, and becomes a cohering and combining force. We
contend that this fluid is the only fluid of space; when condensed it is
positive, and seeks to escape; when rarefied it is negative, and
receives from the contiguous space a restoration of its power. That it
can give and receive, from planetary matter, what we call motion; and
consequently can affect the temperature of such matter, and be in turn
affected by it. And finally that, for its degree of inertia, it exceeds
in elasticity and specific heat all other matter.
PROCESS OF DERANGEMENT.
This premised, we see that as the axis of the vortex traverses the
surface of the earth, there is a tendency to derange the electric state
of the parts travelled over, by bringing the atmosphere and surface of
the earth under the rarefied centre of the vortex. For it is not the
ether of the atmosphere alone that is affected. It is called forth from
the earth itself, and partakes of the temperature of the
crust,--carrying up into the upper regions the vapor-loaded atmosphere
of the surface. The weather now feels close and warm; even in winter
there is a balmy change in the feelings. The atmosphere then fills with
haze, even to the highest regions of the clouds; the clouds themselves
are ill defined; generally the wind comes in at E. S-E., or S., getting
very fresh by the time it chops round to W. In from six to twelve hours
from the time of the meridian passage, in this latitude, the Big Cumuli
have formed, and commenced their march eastward. In summer time there is
always thunder and lightning, when the passage is attended or followed
by a storm. In winter, generally, but not always. In summer, the
diameter of the storm is contracted; in winter, dilated; in consequence
of this, summer is the best season to trace the vortices of the earth
through their revolutions. Let us now attend a little to the results.
The ether of the surface atmosphere partakes of the temperature of that
atmosphere, so also the ether of the earth's crust partakes of the
temperature of the crust; and its escape is rapid, compared with the
ascent of the air. When it arrives at the colder layers of air above,
its temperature sinks, and, on account of the greater specific caloric,
it imparts a much higher temperature to those layers than is due to
their position; an elevation consequently takes place,--begetting a
drain from below, until the upper regions are loaded with a warm and
vapory atmosphere. If the action of the sun conspires at the same time
to increase the effect, the storm will be more violent. In twelve hours
after the meridian passage of the vortex, the storm is brought under the
parts of the ethereal atmosphere of the earth most remote from the axis;
a reaction now takes place; the cold ether of space rushes in, and, on
account of its great specific caloric, it abstracts from the warm
atmosphere more than pertains to the difference of temperature, and
there is a great condensation. Rain and hail may form in fearful
quantities; and when the equilibrium is restored, the temperature will
have fallen many degrees.
As it is important that we should have a clear view of the character of
the ether, we will revert to the principle we have advocated, viz.: that
in equal spaces there are equal momenta. What the ether wants in
inertia, is made up by its motion or specific heat, considering in this
case inertia to stand for weight when compared with ponderable matter;
so that to raise an equivalent amount of inertia of ether to the same
temperature as atmospheric air, will require as much more motion or
specific heat as its matter is less. And this we conceive to be a law of
space in relation to all free or gaseous matter. To apply it to solids
would require a knowledge of the amount of force constituting the
cohesion of the solid.
INFLUENCE OF DIMINISHED PRESSURE.
But there is another principle which modifies these effects. We have
already adverted to the action of the tangential current of the vortex
forcing the outer layers of the atmosphere into waves. These waves will
be interfered with by the different vortices, sometimes being increased
and sometimes diminished by them.[6] If these waves are supposed very
wide, (which would be the case in the attenuated outside layers of the
atmosphere,) the action of the vortex will be greater in its passage
over a place, which at the time corresponded to the depression point of
the wave, that is, to the line of low barometer; because here there
would be less resistance to overcome in the passage of the ether from
the surface of the earth into space; so that we may conceive each vortex
making a line of storms each day around the earth, separated by less
disturbed intervals. After the formation of the storm, it of course has
nothing to do with the vortex that produced it; it travels in the
general direction of the local atmosphere of the place--in intratropical
latitudes westward, in extratropical latitudes eastward. If, therefore,
the disturbance forms at the place of observation, there will probably
be no storm; but further eastward its action would be more apparent or
violent. It is impossible, of course, to lay down any general
description which shall meet every case. It is a knowledge that can only
be acquired by observation, and then is not readily or easily
communicated. There are many contingencies to be allowed for, and many
modifying causes to keep sight of, to enter into which would only be
tedious; we shall, therefore, confine ourselves to the prominent
phenomena.
ACTION OF THE POLAR CURRENT.
We have seen how the passage of the axis of the vortex may derange the
electric tension of the parts passed over; but there is another mode of
action not yet adverted to.
[Illustration: Fig. 1]
When the moon is at her perigee, the axis of the vortex passes through
the centre of gravity of the earth and moon at C, and cuts off the
segment RR. At the apogee, on account of her greater distance, and of
her consequent power to _push_ the earth out from the axis of the vortex
XX, the segment R′R′ is only cut off by the axis; and the angle which
the axis makes with the surface will vary with the arcs AR and A′R′; for
these arcs will measure the inclination from the nature of the circle.
In passing from the perigee to the apogee the axis will pass over the
latitudes intermediate between R and R′ in both hemispheres, neither
reaching to the equator E, nor to the pole P. Let us now suppose a
meridian of the earth, represented by the line NRS, N being north, and S
south, and the surface of the atmosphere by N′S′; XX still representing
the axis of the vortex, ordinarily inclined 34° or 35° to the surface.
Let us also conceive the rotation of the earth to cease, (the action of
the vortex remaining the same,) thus leaving the axis over a particular
longitude. If the ether possesses inertia, there will be an actual
scooping out of the upper portions, driving them southward to a certain
distance, where the atmosphere will be piled up above the ordinary
level. There will, therefore, be a strong contrary current at the
surface of the earth to restore the equilibrium, and if the action be
violent, the surface wind will be increased; so that if it be considered
tangential to the surface at S, its own momentum will tend to make it
leave the surface and mount up to T; and in this way increase the action
due to the ether. Now, although the axis is never stationary, but
travels round the earth in less than twenty-five hours, yet there is a
tendency to this mode of action; and it is even sometimes palpable to
the observer when the axis has passed immediately to the northward; for
the pinnate shafts and branching plumes of the cirri often reach far to
the south of the southern boundary of the storm. These shafts are always
longer when radiating from the northward than when proceeding from the
southward. The cause is understood by the above figure. At such a time,
after dark, the auroral shafts will also be seen over the storm to the
northward, but will be invisible to those beneath. There is this to be
observed, however, that the visibility of the ethereal current (or the
aurora) is more frequent when the passage of the vortex is not attended
with any great commotion, its free passage being perhaps obstructed by
too dry an atmosphere; hence it becomes more visible. But it may be
asserted that a great aurora is never seen except when a vortex is near,
and to the northward, and within a few hours of its passage over the
meridian. We have, however, seen partial auroras to the south when none
existed north, and also cases when the radiation was from west, but they
are never as bright as in the north. They are all due, however, to the
same cause; and we have frequently followed a vortex for three days to
the northward, (that is, seen the effects of its meridian passage,) at
700 miles distance, by the aurora, and even by the lightning, which
proves plainly that the _exterior layers_ of our atmosphere can reflect
a flash of lightning, assisted by the horizontal refraction, otherwise
the curvature of the earth would sink it ten miles below the horizon.
[Illustration: Fig. 2]
LIMITS OF THE VORTEX.
The action of the polar current of the ether, therefore, tends to cause
a depression of the barometer, and an elevation to the _northward_ and
southward, and there is a general set of the wind below to the point of
greatest depression. The action of the tangential current works the
outer surface of the atmosphere into great ridges and hollows, whose
distances apart as well as actual dimensions, are continually changing
under the influences of causes not yet alluded to, and it is in the
hollows where the action of the polar current will be principally
expended. Luckily for the earth, the axis of the vortex is never long in
passing over any particular place. In this latitude, whose natural
cosine is three-fourths, the velocity _westward_ is over 700 miles per
hour; but at its extreme limits north, the motion is much slower, and is
repeated for two or three days in nearly the same latitude, for then it
begins to return to the south; thus oscillating in about one sidereal
period of the moon. At its southern limit, the vortex varies but slowly
in latitude for the same time, but the velocity is much greater. The
extreme latitudes vary at different times with the eccentricity of the
lunar orbit, with the place or longitude of the perigee, and with the
longitude of the moon's ascending node, but in no case can the _central
vortex_ reach within 5° of the equator, or higher than about 75° of
latitude north or south. Hence there are no storms strictly speaking
beyond 88°[7] of latitude; although a storm may be raging close by, at
the turning point south, and draw in a very strong gale from the
northward with a clear sky above. So also, although rains and short
squalls may be frequent in the vapor-loaded atmosphere of the equator,
yet the hurricane does not reach there, owing to the adjustment of the
mass and distance of the moon, and the inclination of the axes of the
vortices to the axis of the earth. If the temperature of the upper limit
or highest latitude of the vortex, was equal to the temperature which
obtains at its lowest limit, and the daily extremes of the solar
influence as great, the hurricanes would be as violent at the one as the
other, and even more so on account of the smaller velocity. But the
deficiency of temperature and moisture, (which last is all-important,)
prevents the full development of the effect. And even in the tropics,
the progress of the sun, by its power in directing the great annual
currents of the atmosphere, only conspires in the summer and autumn
months, to bring an atmosphere in the track of the vortices, possessing
the full degree of moisture and deficiency of electric tension, to
produce the derangement necessary to call forth the hurricane in its
greatest activity.
ROUTINE OF A STORM.
The novelty and originality of this theory will perhaps justify us in
dwelling a little longer on what observation has detected. The vortex
(and we are now speaking only of the central vortex) does not derange
every place alike, but _skips_ over large tracts of longitude in its
progress westward. We speak here of the immovable axis of the vortex as
in motion; in reality it is the rotation of the earth which brings every
meridian under its influence in some latitude once every twenty-four
hours. The centre of greatest derangement forms the nucleus, towards
which the surface currents, under certain restrictions, flow. The
strongest current will, however, usually be from the south, on account
of the inclination of the axis of the vortex to the surface of the
earth.[8] These currents continuing onwards by their vires inertiæ,
according to the first law of motion, assist somewhat in conveying the
warm surface wind, loaded with moisture, into the region of cloud; and
the diminution of temperature causes the condensation of large masses of
vapor, according to Hutton's views; and the partial vacuum thus
produced, causes a still greater intermingling. But we have already
shown that this is not the sole cause, nor is it ever more than
partially accomplished. The ether of the lower atmosphere, and of the
crust of the earth, is disturbed, and rushes towards the rarefied axis
from the surface, and with the temperature of the surface, thus
conveying the surface atmosphere, in a measure, along with it. In the
upper regions, this ether (or electric fluid) cools down, or parts with
some of its heat, to the air of those regions, and, by its great
specific caloric, necessarily and unduly increases the temperature of
the air. This, by its expansion and ascension will cause a further
influx from below, until the upper atmosphere becomes loaded with vapor.
In twelve hours, at least, a reaction must take place, as that part of
the earth's surface is carried six or seven thousand miles from the
axis, where the ether is more dense. This in turn descends to the
surface, carrying with it the temperature of space, at least 60° below
zero; a great condensation must follow; local derangements of the
electric equilibrium in the centre of large clouds, when the
condensation is active, must now take place, while partially
nonconducting masses intervene, to prevent an instantaneous restoration
of the equilibrium, until the derangement is sufficient to cause the
necessary tension, when all obstacles are rent asunder, and the ether
issues forth, clothed in the power and sublimity of the lightning. It is
a fearfully-energetic fluid, and, when sufficiently disturbed, competent
to produce the most violent tornado, or the most destructive earthquake.
That these two phenomena have simultaneously occurred, seems well
authenticated; but the earthquake, of course, must be referred generally
to derangements of the electric equilibrium of the earth's interior, of
which at present we know but little.
The day or morning previous to the passage of the vortex, is frequently
very fine, calm, mild, and sleepy weather,--commonly called a weather
breeder. After the storm has fully matured, there is an approach of the
clouds to the surface, a reduction of the temperature above, and the
human body feels the change far more than is due to the fall of
temperature. This is owing to the cold ether requiring so much heat to
raise its temperature to that of surrounding bodies, or, in other words,
is due to its great specific caloric. In summer, this falling of the
upper layers in front of the storm is so apparent, that every part is
seen to expand under the eye by perspective,--swelling, and curling, and
writhing, like the surface of water or oil when just commenced boiling.
The wind now partakes of the motion of the external ether, and moves
with the storm eastward (in this latitude), or from N-E. to S-E., until
the action ceases.
CONDITIONS NECESSARY TO PRODUCE A STORM.
The vortex, in its passage round the earth, may only meet with a few
localities favorable for producing a very violent storm; but these
nuclei will generally be connected by bands of cloudy atmosphere; so
that could we view them from the moon, the earth would be belted like
the planet Jupiter. There is reason to suspect, also, that there are
variations in the energy of the ethereal motions, independent of the
conditions of the earth and its atmosphere, which affects even the
radial stream of the sun. For the zodiacal light, which is caused by
this radial stream, is at times much more vivid than at others. Also in
the case of the aurora, on our own globe. On this point there is much to
say, but here is not the place. The conditions favorable for the
production of a storm at the _central_ passage of a vortex, are a
previous exemption from excitement _ceteris paribus_, a high temperature
and dew point, a depression of the barometer, and local accumulation of
electric tension, positive or negative; and these are influenced by the
storms in other places controlling the aërial currents, and thus
determining the atmosphere of the place.
LATERAL VORTICES.
We have already alluded to the lateral vortices of the terral system. We
must now resort to a diagram.
In the following figure, the arrows represent the ethereal current of
the terral vortex; the linear circle, the earth; C the centre of gravity
of the earth and moon, and, consequently, the central vortex or axis of
the vortex of the earth, I represents the position of the inner vortex,
and O that of the outer vortex. These two last are eddies, caused by the
obstacle presented by the earth in being _pushed_ out from the centre by
the moon, and are called lateral vortices. There are, therefore, two
lateral vortices, and one central, in both hemispheres, and by this
simple arrangement is the earth watered, and the atmospheric circulation
produced.
[Illustration: Fig. 3]
ILLUSTRATION OF THEIR ACTION.
If we place a globe in a vessel of water, so that the vertex shall only
just be covered, and place the globe eccentrically in the vessel so that
the centre of the vessel may not be too far from the outside of the
globe, and then impart an equable but slow motion to the water, in the
manner of a vortex; by viewing the reflected light of the sky from the
surface of the water above the globe, we shall be able to trace a
succession of dimples, originating at I and O, and passing off with the
current, and dying away. The direction of the fluid in these little
eddies, will be the same as the direction of the current in the main
vortex. If we displace the globe, so as to remove it far from the centre
of the vessel, and impart the same motion, the vortex I will be found at
E, and the direction of the current will be contrary to the direction
of the fluid in the vessel. In the case of the earth and moon, the
displacement can never change the position of the inner vortex much. It
will always be to the right hand of the central vortex in north
latitudes, and in consequence of the ether striking our globe in such a
position, the current that is deflected from its true path, by the
protuberance of the earth forcing it inside, is prevented by the
circular current of the parts nearer the axis of the vortex, from
passing off; so that a vortex is formed, and is more violent, _ceteris
paribus_, than the vortex at O.
ORDER OF OCCURRENCE.
Whether this mode of action has been correctly inferred, matters little;
the lateral vortices follow the law of such a position. The inner vortex
always precedes the central from five to eight days, when ascending in
this latitude, and comes to the meridian after the moon. The outer
vortex, on the contrary, follows the central in its monthly round, and
comes to the meridian before the moon. It will be readily understood
that if the axes of these lateral vortices be produced through the
earth, they will pass through similar vortices in the opposite
hemisphere; but as the greatest latitude of the one, corresponds to the
least latitude of the other, the same calculation will not answer for
both. The same remark applies to the central vortex also.
Thus there are six passages each month over latitude 41°; but as there
are intervals of 3° to 6° between two consecutive passages of the same
vortex, it may happen that an observer in the middle latitude, would
perhaps see nothing of their effects without looking for them. Generally
speaking, they are not only seen, but felt. The time of the passage of
the outer vortex ascending, corresponds so nearly (in 38° of latitude)
at certain times, with the passage of the central vortex descending,
that the two may be considered one if attention is not directed to it.
The orbits of these lateral vortices depend, like that of the central
vortex, on the orbit of the moon for eccentricity, but the longitudes of
the perigee will not correspond with the longitude of the moon's
perigee. This follows from the theory. As the elements of these orbits
are only approximately determined, we shall confine our calculations to
the orbit of the central vortex.
REDFIELD'S THEORY OF STORMS.
It will now appear plainly to the reader, that this theory of storms
differs in every particular from the rival theories of Redfield and
Espy, both as to the cause and the _modus agendi_. It would appear at
first sight, as if the discovery of these vortices would at once remedy
the great defect in the theory of Redfield, viz.: that no adequate cause
is assigned for the commencement and continuation of the vorticose
motion, in the great circular whirlwinds which compose a storm. The
facts, however, are adverse to such an application. According to
Mr. Redfield, the rotation of a circular storm in the northern
hemisphere is from right to left, and the reverse in the southern. The
author's attention has, of course, been considerably directed to this
point; but in every case he has been unfortunate in finding in the
clouds a rotation from left to right. Some cases are mentioned in the
appended record of the weather. He has also noticed many of those small
whirlwinds on arid plains, in Egypt, in Mexico, and in California,
which, in the great majority of cases, were also from left to right. His
opportunities, however, have not extended to the southern hemisphere.
This theory has not, however, been formed on theoretic views, but by
looking nature in the face for years, and following her indications.
Accordingly, we find that the changes of the wind in a storm forbid the
adoption of the circular hypothesis.
WHIRLWINDS VERY LIMITED IN DIAMETER.
The theory, as extended by Col. Reid, rests on a simple rotation around
a progressing centre, and is found sometimes supported by evidence of
the most violent action at the centre, and sometimes by showing that the
central portion is often in a state of calm. We do not attempt to
reconcile these views; but would merely observe, that an atmospheric
vortex must be subject to the same dynamical laws as all other vortices;
and inasmuch as the medium cannot differ greatly in density, from the
centre to the circumference, the periodic times of the parts of the
vortex, must be directly as their distances from the axis, and
consequently the absolute velocities must be equal. If Mr. Redfield
resorts to a spirally inward current, it would be a centripetal instead
of a centrifugal current, and therefore could not cause the barometer to
fall, which was the best feature of the theory in its primitive form.
The absolute velocity of the wind is the important element which most
concerns us. In the case of a tornado of a few yards in diameter, there
is no doubt a circular motion, caused by the meeting of opposing
currents; but this may be considered a circle of a very small diameter.
The cause is due to a rapid escape of electric or ethereal matter, from
the crust of the earth, called forth by the progressing, disturbed space
above; this involves the air, and an ascending column in rotation begets
the rush on all sides to that column in straight lines: consequently,
the velocities will be inversely as the distances from the axis, and the
force of the current as the squares of the velocities. On the circular
theory, no increase of velocity would be conferred by the approach of
the centre, and consequently no increase of power.
OBJECTION TO CIRCULAR STORMS.
Another objection to the circular theory of storms, is the uniformity of
phase. If that theory be true, we see no reason why a person should not
be sometimes on the northern side of the gale. By referring to a
diagram, we perceive that on the northern side the changes of the wind
pursue a contrary direction to what they do on the south, yet in nine
cases out of ten, each vessel meeting a hurricane will find the same
changes of wind as are due to the southern side of the storm. It is
true, that if a vessel be to the northward of a great hurricane, there
will almost certainly be a north-east gale drawn in, and this might be
set down as the outer limits of a circular storm. But when the storm
really begins, the wind comes round south-east, south, south-west,
ending at north-west, and frequently is succeeded, on the following day,
(if in middle latitude,) by a moderate breeze from the northward. Now,
if the north-east gale spoken of above, was the outer limits of an
atmospheric vortex, a vessel sailing west ought not to meet the
hurricane, as a north-east wind is indicative of being already on the
west side, or behind the storm.
Again, the characters of the winds, and appearances at the different
changes, are opposed to the circular theory. At a distance of fifty
miles from the centre of a storm, the wind which passes over a ship as a
southerly wind, will have made a rotation and a half, with the hurricane
velocity, before the same wind can again pass the ship as a northerly
wind, (supposing the progress eastward, and the ship lying to,) that is,
the same wind which in another place was a south wind two hours before,
and after only going one degree north, becomes a northerly
wind,--changed in character and temperature, as every seaman is well
aware. In a storm, if the circular theory be true, the character and
temperature should be the same, no matter from what point the wind is
blowing. This should be a conclusive argument.
Mr. Espy has also changed his ground on the storms of the United States;
he does not now contend that the winds blow inwards to a centre, but to
a line either directly or obliquely. Thus we see that while Mr. Redfield
concedes to Mr. Espy a spirally inward current, the latter also gives up
a direct current to the centre, to Mr. Redfield. This shows at least an
approximation to the truth.
It is not necessary for the support of this theory, that we should
derive any materials from the ruins of others; we shall therefore not
avail ourselves of certain discrepant results, which can be found in
many of the storms cited by Colonel Reid. With respect to Mr. Espy's
_cause_ of storms, the experiments of Regnault may be considered as
decisive of the question:--1st, because the specific heat of vapor is so
much less than Espy assumed it to be; and 2d, because the expansion of
air in a free space does not suffer any change of volume by ascending,
except what is due to diminished pressure, and the natural temperature
of that elevation.
INDICATIONS OF A STORM.
In accordance with our theory, the direction and force of the wind in a
storm are due to ascending columns of air, supplied from the upper
portion of the atmospheric stratum beneath the clouds. The commotion
begins at the highest limits of the cirri, and even at greater
elevations. Hence, the hazy appearance of the sky is a legitimate
precursor of the coming gale. As a general thing, the wind will blow (at
the surface) towards the centre of greatest commotion, but it is too
dependent on the ever-varying position and power of temporary nuclei of
disturbance, to be long steady, except when the disturbance is so remote
that its different centres of induction are, as it were, merged into one
common focus. When a vortex is descending, or passing from north to
south, and withal very energetic at the time, the southerly wind (which
may always be considered the principal wind of the storm in this
hemisphere) may blow steadily towards the vortex for three or even four
days. When a vortex is ascending, the induced northerly current will be
comparatively moderate, and be frequently checked by the southerly wind
overblowing the storm, and arriving the day before the vortex which
produced it.
The important point for the navigator, is to know the time of meridian
passage of the vortex, and its latitude at the time of the passage, and
then be guided by the indications of the weather and the state of
barometer. If it commences storming the day before the passage, he may
expect it much worse soon after the passage; and again, if the weather
looks bad when no vortex is near, he may have a steady gale setting
towards a storm, but no storm until the arrival of a vortex. Again, if
the barometer is low the day before the vortex passes, there may be high
barometer to the west, and the passage be attended by no great
commotion, as it requires time for the storm to mature, and consequently
its greatest violence will be to the east. If at the ship the barometer
is high, the vortex may still produce a storm on a line of low barometer
to the west, and this line may reach the ship at the time of the
passage. In tropical climates the trouble must be looked for to the
eastward; as a storm, once excited, will travel westward with that
stratum of atmosphere in which the great mass of vapor is lodged, and in
which, of course, the greatest derangement of electric tension is
produced.
It will now be seen that we do not admit, with Col. Reid, that a storm
continues in existence for a week together. Suppose a hurricane to
originate in the Antilles at the southern limits of a vortex, the
hurricane would die away, according to our theory, if the vortex did not
come round again and take up the same nucleus of disturbance. On the
third day the vortex is found still further north, and the apparent path
of the hurricane becomes more curved. In latitude 30° the vortex passes
over 3° or 5° of latitude in a day; and here being the latitude where
the lower atmospheric current changes its course, the storm passes due
north, and afterwards north-east. Now, each day of the series there is a
distinct hurricane, (caused by an increase of energy in a particular
vortex, as we have before hinted,) each one overlapping on the remains
of the preceding; but in each the same changes of the wind are gone
through, and the same general features preserved, as if it were truly a
progressive whirlwind, except that each vessel has the violent part of
it, as if she was in the southern half of the whirl. The apparent
regularity of the Atlantic storms in direction, as exhibited by Col.
Reid, are owing in a great degree to the course of the Gulf Stream, in
which a vortex, in its successive passages in different latitudes, finds
more favorable conditions for the development of its power, than in
other parts of the same ocean; thus showing the importance of regarding
the established character of storms in each locality, as determined by
observation. In this connection, also, we may remark, that the meridians
of greatest magnetic intensity are, _ceteris paribus_, also the
meridians of greatest atmospheric commotion. The discovery of this fact
is due to Capt. Sabine. The cause is explained by the theory.
As it is the author's intention to embody the practical application of
this theory to navigation, with the necessary rules and tables, in a
separate work, sufficient has been said to familiarize the reader with
the general idea of a cause external to the earth, as the active motor
in all atmospheric phenomena. We will therefore only allude in a general
way to the principal distinguishing feature of the theory. We say, then,
that the wind in a storm is not in rotation, and it is a dangerous
doctrine to teach the navigator. We also assert as distinctly, that the
wind _in_ a storm does not blow from all sides towards the centre, which
is just as dangerous to believe. If it were wise to pin our faith to any
Procrustean formula, we might endorse the following propositions: That
at the beginning of a storm the wind is from the equator towards the
poles in every part of the storm; that, at a later date, another current
(really a polar current deflected by convection) sets in at right angles
to the first one; and that at the end of the storm there is only _one_
wind blowing at right angles to the direction at the beginning. Outside
the storm, considered as a hundred, or two or three hundred miles in
diameter, there is, under certain limitations, a surface wind setting
towards the general focus of motion and condensation, and this surface
wind will be strongest from the westward, on account of the motion of
the whole atmosphere in which these other motions are performed being to
the eastward.[9] The whole phenomenon is electrical or magnetic, or
electro-magnetic or ethereal, whichever name pleases best. The vortex,
by its action, causes a current of induction below, from the equator, as
may be understood by inspecting Fig. 2, which in the northern hemisphere
brings in a southerly current by convection: the regular circular
current, however, finally penetrates below, as soon as the process of
induction has ceased; and thus the polar current of the atmosphere at
last overcomes the equatorial current in a furious squall, which ceases
by degrees, and the equilibrium is restored.
Every locality will have its peculiar features; in each, the prevailing
wind will be at right angles to the magnetic meridian, and the progress
of the storm will tend to follow the magnetic parallel, which is one
reason why the Atlantic and Indian Ocean storms have been mistaken for
progressive whirlwinds. When these views are developed in full, the
mariner can pretty certainly decide his position in the storm, the
direction of its progress, and its probable duration.
FOOTNOTES:
[3] The specific heat of the ether being a constant factor, it may be
divided out.
[4] A term adopted by Prof. Faraday to denote the mode in which bodies
are carried along by an electrical current.
[5] Ottawa, Ill.
[6] The principal cause of these waves is, no doubt, due to the
vortices, and the eastern progress of the waves due to the rotating
ether; but, at present, it will not be necessary to separate these
effects.
[7] The inner vortex may reach as high as 83° when the moon's orbit is
favorably situated.
[8] The curvature of the earth is more than 10 miles in a distance of
300 miles.
[9] In middle latitudes.
SECTION SECOND.
MECHANICAL ACTION OF THE MOON.
We will now proceed to give the method of determining the latitude of
the axis of the vortex, at the time of its passage over any given
meridian, and at any given time. And afterwards we will give a brief
abstract from the record of the weather, for one sidereal period of the
moon, in order to compare the theory with observation.
[Illustration: Fig. 4]
In the above figure, the circle PER represents the earth, E the equator,
PP′ the poles, T the centre of the earth, C the mechanical centre of the
terral vortex, M the moon, XX′ the axis of the vortex, and A the point
where the radius vector of the moon pierces the surface of the earth. If
we consider the axis of the vortex to be the axis of equilibrium in the
system, it is evident that TC will be to CM, as the mass of the moon to
the mass of the earth. Now, if we take these masses respectively as 1 to
72.3, and the moon's mean distance at 238,650 miles, the mean value of
TC is equal to this number, divided by the sum of these masses,--_i.e._
the mean radius vector of the little orbit, described by the earth's
centre around the centre of gravity of the earth and moon, is equal
238650/(72.3+1) = 3,256 miles; and at any other distance of the moon, is
equal to that distance, divided by the same sum. Therefore, by taking CT
in the inverse ratio of the mean semi-diameter of the moon to the true
semi-diameter, we shall have the value of CT at that time. But TA is to
TC as radius to the cosine of the arc AR, and RR′ are the points on the
earth's surface pierced by the axis of the vortex, supposing this axis
coincident with the pole of the lunar orbit. If this were so, the
calculation would be very short and simple; and it will, perhaps,
facilitate the investigation, by considering, for the present, that the
two axes do coincide.
In order, also, to simplify the question, we will consider the earth a
perfect sphere, having a diameter of 7,900 miles, equal to the actual
polar diameter, and therefore TA is equal to 3,950 miles.
In the spherical triangle given on next page, we have given the point A,
being the position of the moon in right ascension and declination in the
heavens, and considered as terrestrial latitude and longitude.
Therefore, PA is equal to the complement of the moon's declination, P
being the pole of the earth, and L being the pole of the lunar orbit; PL
is equal to the obliquity of the lunar orbit, with respect to the earth,
and is therefore given by finding the true inclination of the lunar
orbit at the time, equal EL, (E being the pole of the ecliptic,) also
the true longitude of the ascending node, and the obliquity of the
ecliptic PE. Now, as we are supposing the axis of the vortex parallel
to the pole of the lunar orbit, and to pierce the earth's surface at R,
ARL will evidently all be in the same plane; and, as in the case of A
and L, this plane passes through the earth's centre, ARL must all lie in
the same great circle. Having, therefore, the right ascension of A, and
the right ascension of L, we have the angle P. This gives us two sides,
and the included angle, to find the side LA. But we have before found
the arc AR; we therefore know LR. But in finding LA, we found both the
angles L and A, and therefore can find PR, which is equal to the
complement of the latitude sought.
[Illustration: Fig. 5]
We have thus indicated briefly the simple process by which we could find
the latitude of the axis of the central vortex, supposing it to be
always coincident with the pole of the lunar orbit. The true problem is
more complicated, and the principal modifications, indicated by the
theory, are abundantly confirmed by observation. The determination of
the inclination of the axis of the vortex, its position in space at a
given time, and the law of its motion, was a work of cheerless labor for
a long time. He that has been tantalized by hope for years, and ever on
the eve of realization, has found the vision vanish, can understand the
feeling which proceeds from frequent disappointment in not finding that,
whose existence is almost demonstrated; and more especially when the
approximation differs but slightly from the actual phenomena.
The chief difficulty at the outset of these investigations, arose from
the conflicting authority of astronomers in relation to the mass of the
moon. We are too apt to confound the precision of the laws of nature,
with the perfection of human theories. Man observes the phenomena of the
heavens, and derives his means of predicting what will be, from what has
been. Hence the motions of the heavenly bodies are known to within a
trifling amount of the truth; but it does not follow that the true
explanation is always given by theory. If this were so, the mass of the
moon (for instance) ought to be the same, whether deduced from the
principle of gravitation or from some other source. This is not so.
Newton found it 1/40 of that of the earth. La Place, from a profound
theoretical discussion of the tides, gave it as 1/58.6, while from other
sources he found a necessity of diminishing it still more, to 1/68, and
finally as low as 1/75. Bailly, Herschel, and others, from the nutation
of the earth's axis, only found 1/80, and the Baron Lindenau deduced the
mass from the same phenomenon 1/88. In a very recent work by Mr. Hind,
he uses this last value in certain computations, and remarks, that we
shall not be very far wrong in considering it as 1/80 of the mass of the
earth. This shows the uncertainty of the matter in 1852. If astronomy is
so perfect as to determine the parallax of a fixed star, which is almost
always less than one second, why is it that the mass of the moon is not
more nearly approximated? Every two weeks the sun's longitude is
affected by the position of the moon, alternately increasing and
diminishing it, by a quantity depending solely upon the relative mass of
the earth and moon, and is a gross quantity compared to the parallax of
a star. So, also, the horizontal parallax--the most palpable of all
methods--taken by different observers at Berlin, and the Cape of Good
Hope, (a very respectable base line, one would suppose,) makes the mass
of the moon greater than its value derived from nutation; the first
giving about 1/70, the last about 1/74.2. Does not this declare that it
is unsafe to depend too absolutely on the strict wording of the
Newtonian law of gravitation. Happily our theory furnishes us with the
correct value of the moon's mass, written legibly on the surface of the
earth; and it comes out nearly what these two phenomena always gave it,
viz.: 1/72.3 of that of the earth. In another place we shall inquire
into the cause of the discrepancy as given by the nutation of the earth.
MOTION OF THE AXIS OF THE VORTEX.
If the axis of the terral vortex does not coincide with the axis of the
lunar orbit, we must derive this position from observation, which can
only be done by long and careful attention. This difficulty is increased
by the uncertainty about the mass of the moon, already alluded to, and
by the fact that there are three vortices in each hemisphere which pass
over _twice_ in each month, and it is not _always_ possible to decide by
observation, whether a vortex is ascending or descending, or even to
discriminate between them, so as to be assured that this is the central
descending, and that the outer vortex ascending. A better acquaintance,
however, with the phenomenon, at last dissipates this uncertainty, and
the vortices are then found to pursue their course with that regularity
which varies only according to law. The position of the vortex (the
central vortex is the one under consideration) then depends on the
inclination of its axis to the axis of the earth, and the right
ascension of that axis at the given time. For we shall see that an
assumed immobility of the axis of the vortex, would be in direct
collision with the principles of the theory.
Let the following figure represent a globe of wood of uniform density
throughout. Let this globe be rotated round the axis. It is evident that
no change of position of the axis would be produced by the rotation. If
we add two equal masses of lead at m and m′, on opposite sides of the
axis, the globe is still in equilibrium, as far as gravity is concerned,
and if perfectly spherical and homogeneous it might be suspended from
its centre in any position, or assume indifferently any position in a
vessel of water. If, however, the globe is now put into a state of rapid
rotation round the axis, and then allowed to float freely in the water,
we perceive that it is no longer in a state of equilibrium. The mass m
being more dense than its antagonist particle at n, and having equal
velocity, its momentum is greater, and it now tends continually to pull
the pole from its perpendicular, without affecting the position of the
centre. The same effect is produced by m′, and consequently the axis
describes the surface of a double cone, whose vertices are at the centre
of the globe. If these masses of lead had been placed at opposite sides
of the axis on the _equator_ of the globe, no such motion would be
produced; for we are supposing the globe formed of a hard and unyielding
material. In the case of the ethereal vortex of the earth, we must
remember there are two different kinds of matter,--one ponderable, the
other not ponderable; yet both subject to the same dynamical laws. If we
consider the axis of the terral vortex to coincide with the axis of the
lunar orbit, the moon and earth are placed in the equatorial plane of
the vortex, and consequently there can be no derangement of the
equilibrium of the vortex by its own rotation. But even in this case,
seeing that the moon's orbit is inclined to the ecliptic, the
gravitating power of the sun is exerted on the moon, and of necessity
she must quit the equatorial plane of the vortex; for the sun can exert
no influence on the _matter_ of the vortex by his attracting power. The
moment, however, the moon has left the equatorial plane of the vortex,
the principle of momentum comes into play, and a conical motion of the
axis of the vortex is produced, by its seeking to follow the moon in her
monthly revolution. This case is, however, very different to the
illustration we gave. The vortex is a fluid, through which the moon
freely wends her way, passing through the equatorial plane of the vortex
twice in each revolution. These points constitute the moon's nodes on
the plane of the vortex, and, from the principles laid down, the force
of the moon to disturb the equilibrium of the axis of the vortex,
vanishes at these points, and attains a maximum 90° from them. And the
effect produced, in passing from her ascending to her descending node,
is equal and contrary to the effect produced in passing from her
descending to her ascending node,--reckoning these points on the plane
of the vortex.
[Illustration: Fig. 6]
INCLINATION OF THE AXIS.
By whatever means the two planes first became permanently inclined, we
see that it is a necessary consequence of the admission of these
principles, not only that the axis of the vortex should be drawn aside
by the momentum of the earth and moon, ever striving, as it were, to
maintain a dynamical balance in the system, in accordance with the
simple laws of motion, and ever disturbed by the action of gravitation
exerted on the grosser matter of the system; but also, that this axis
should follow, the axis of the lunar orbit, at the same mean
inclination, during the complete revolution of the node. The mean
inclination of the two axes, determined by observation, is 2° 45′, and
the monthly equation, at a maximum, is about 15′, being a plus
correction in the northern hemisphere, where the moon is between her
descending and ascending node, reckoned on the plane of the vortex, and
a minus correction, when between her ascending and descending node. And
the mean longitude of the node will be the same as the true longitude of
the moon's orbit node,--the maximum correction for the true longitude
being only about 5° ±.
[Illustration: Fig. 7]
In the following figure, P is the pole of the earth; E the pole of the
ecliptic; L the pole of the lunar orbit; V the mean position of the pole
of the vortex at the time; the angle ♈EL the true longitude of the pole
of the lunar orbit, equal to the _true_ longitude of the ascending node
± 90°. VL is therefore the mean inclination ± 2° 45′; and the little
circle, the orbit described by the pole of the vortex _twice_ in each
sidereal revolution of the moon. The distance of the pole of the vortex
from the mean position V, may be approximately estimated, by multiplying
the maximum value 15′ by the sine of twice the moon's distance from the
node of the vortex, or from its mean position, viz.: the true longitude
of the ascending node of the moon on the ecliptic. From this we may
calculate the true place of the node, the true obliquity, and the true
inclination to the lunar orbit. Having indicated the necessity for this
correction, and its numerical coefficient, we shall no longer embarrass
the computation by such minutiæ, but consider the mean inclination as
the true inclination, and the mean place of the node as the true place
of the node, and coincident with the ascending node of the moon's orbit
on the ecliptic.
POSITION OF THE AXIS OF THE VORTEX.
It is now necessary to prove that the axis of the vortex will still pass
through the centre of gravity of the earth and moon.
[Illustration: Fig. 8]
Let XX now represent the axis of the lunar orbit, and C the centre of
gravity of the earth and moon, X′X′ the axis of the vortex, and KCR the
inclination of this axis. Then from
similarity Ct : Tt :: Cm : Mm
but Tt : Mm :: Moon's mass : Earth's mass.
That is Tt : Mm :: TC : MC.
Therefore the system is still balanced; and in no other point but the
point C, can the intersection of the axes be made without destroying
this balance.
It will be observed by inspecting the figure, that the arc R′K′ is
greater than the arc RK. That the first increases the arc AR, and the
second diminishes that arc. The arc R′K′ is a plus correction therefore,
and the smaller arc RK a minus correction. If the moon is between her
descending and ascending node, (taking now the node on the ecliptic,)
the correction is negative, and we take the smaller arc. If the moon is
between her ascending and descending node, the correction is positive,
and we take the larger arc. If the moon is 90° from the node, the
correction is a maximum. If the moon is at the node, the correction is
null. In all other positions it is as the sine of the moon's distance
from the nodes. We must now find the maximum value of these arcs of
correction corresponding to the mean inclination of 2° 45′.
To do this we may reduce TC to Tt in the ratio of radius to cosine of
the inclination, and taking TS for radius.
[Illustration: Fig. 9]
{TC × Cos &c. (inclination 2° 45′)}/R is equal the cosine of the arc SK′
and SK′ + AS = AK′ and AK′ + AR′ = R′K′. But from the nature of the
circle, arc RK + arc R′K′ = angle RCK + angle R′CK′, or equal to double
the inclination; and therefore, by subtracting either arc from double
the inclination, we may get the other arc.
The maximum value of these arcs can, however, be found by a simple
proportion, by saying; as the arc AR, plus the inclination, is to the
inclination, so is the inclination to the difference between them; and
therefore, the inclination, plus half the difference, is equal the
greater arc, and the inclination, minus half the difference, is equal
the lesser; the greater being positive, and the lesser negative.
Having found the arc AR, and knowing the moon's distance from either
node, we must reduce these values of the arcs RK and R′K′ just found, in
the ratio of radius to the sine of that distance, and apply it to the
arc AR or A′R′, and we shall get the first correction equal to the
arc AK or AK′.
Call the arc AR = a
" inclination = n
" distance from the node = d
" arc AK = k
and supposing the value of AK be wanted for the northern hemisphere when
the moon is between her descending and ascending node, we have
n²
-------
a + n
(n - ------- ) sin d.
2
k = a - ----------------------
R
If the moon is between her ascending and descending node, then
n²
-------
a + n
(n - ------- ) sin d.
2
k = a + ----------------------
R
The computation will be shorter, however, if we merely reduce the
inclination to the sine of the distance from the node for the first
correction of the arc AR, if we neglect the semi-monthly motion of the
axis; for this last correction diminishes the plus corrections, and the
first one increases it. If, therefore, one is neglected, it is better to
neglect the other also; especially as it might be deemed affectation to
notice trifling inequalities in the present state of the elements of the
question.
There is one inequality, however, which it will not do to neglect. This
arises from the displacement of the axis of the vortex.
DISPLACEMENT OF THE AXIS.
We have represented the axis of the terral vortex as continually passing
through the centre of gravity of the earth and moon. Now, by following
out the principles of the theory, we shall see that this cannot be the
case, except when the moon is in quadrature with the sun. To explain
this:
[Illustration: Fig. 10]
Let the curve passing through C represent a portion of the orbit of the
earth, and S the sun. From the principles laid down, the density of the
ethereal medium increases outward as the square roots of the distances
from the sun. Now, if we consider the circle whose centre is C to
represent the whole terral vortex, it must be that the medium composing
it varies also in density at different distances from the sun, and at
the same time is rotating round the centre. That half of the vortex
which is exterior to the orbit of the earth, being most dense, has
consequently most inertia, and if we conceive the centre of gravity of
the earth and moon to be in the orbit (as it must be) at C, there will
not be dynamical balance in the terral system, if the centre of the
vortex is also found at C. To preserve the equilibrium the centre of the
vortex will necessarily come nearer the sun, and thus be found between T
and C, T representing the earth, and ☾ the moon, and C the centre of
gravity of the two bodies. If the moon is in opposition, the centre of
the vortex will fall between the centre of gravity and the centre of the
earth, and have the apparent effect of diminishing the mass of the moon.
If, on the other hand, the moon is in conjunction, the centre of the
vortex will fall between the centre of gravity and the moon, and have
the apparent effect of increasing the mass of the moon. If the moon is
in quadrature, the effect will be null. The coefficient of this
inequality is 90′, and depends on the sun's distance from the moon. When
the moon is more than 90° from the sun, this correction is positive, and
when less than 90° from the sun, it is negative. If we call this second
correction C, and the moon's distance from her quadratures Q, we have
the value of C = ±(90′ × sin Q)/R.
[Illustration: Fig. 11]
This correction, however, does not affect the inclination of the axis of
the vortex, as will be understood by the subjoined figure. If the moon
is in opposition, the axis of the vortex will not pass through C, but
through C′, and QQ′ will be parallel to KK′. If the moon is in
conjunction, the axis will be still parallel to KK′, as represented by
the dotted line qq′. The correction, therefore, for displacement, is
equal to the arc KQ or Kq, and the correct position of the vortex on the
surface of the earth at a given time will be at the points Q or q and Q′
or q′, considering the earth as a sphere.
[Illustration: Fig. 12]
In the spherical triangle APV, P is the pole of the earth, V the pole of
the vortex, A the point of the earth's surface pierced by the radius
vector of the moon, AQ is the corrected arc, and PV is the obliquity of
the vortex. Now, as the axis of the vortex is parallel to the pole V,
and the earth's centre, and the line MA also passes through the earth's
centre, consequently AQV will all lie in the same great circle, and as
PV is known, and PA is equal to the complement of the moon's declination
at the time, and the right, ascensions of A and V give the angle P, we
have two sides and the included angle to find the rest, PQ being the
complement of the latitude sought.
We will now give an example of the application of these principles.
_Example._[10] Required the latitude of the central vortex at the time
of its meridian passage in longitude 88° 50′ west, July 2d, 1853.
CENTRAL VORTEX ASCENDING.
Greenwich time of passage 2d. 3h. 1m.
Mean longitude of moon's node 78° 29′
True " " 79 32
Mean inclination of lunar orbit 5 9
True " " 5 13
Obliquity of ecliptic 23 27 32″
Mean inclination of vortex 2 45 0
Then in the spherical triangle PEV,
PE is equal 23° 27′ 32″
EV " 7 58 0
E " 100 28 0
P " 18 5 7
PV " 26 2 32
Calling P the polar angle and PV the obliquity of vortex.
[Illustration: Fig. 13]
To find the arc AR.
By combining the two proportions already given, we have by logarithms:
M.R.V. minor = 3256 Log. 3.512683
M.S.D. of moon = 940″ " 2.973128
P.S.D. of earth = 3950 A. C. 6.403403
Radius 10.000000
T.S.D. of moon 885″.5 A. C. 7.052811
Log. Cosine arc AR = 28° 57′ 3″ 9.942025
---------
As the only variable quantity in the above formula is the "True"
semi-diameter of the moon at the time, we may add the Constant logarithm
2.889214 to the arithmetical complement of the logarithm of the true
semi-diameter, and we have in two lines the log. cosine of the arc AR.
We must now find the arc RK equal at a maximum to 2° 45′. The true
longitude of the moon's node being 79° 32′, and the moon's longitude,
per Nautical Almanac, being 58° 30′, the distance from the node is 21°
2′, therefore, the correction is
-2° 45′ × sin 21° 2′
-arc RK = --------------------- = -59′ 13″
R
To find the correction for displacement.
True longitude of sun at date 100° 30′
" of moon " 58 30
Moon's distance from quadrature 48 0
As the moon is less than 90° from the sun this correction is also
negative, or
-90′ × sin 48°
Arc Kq = --------------- = -1° 6′ 46″.
R
Arc AR = 28° 57′ 3″
RK = - 0° 39′ 13″
Kq = - 1° 6′ 46″
Sum = 26° 51′ 4″ = corrected arc AQ.
We have now the necessary elements in the Nautical Almanac, which we
must reduce for the instant of the vortex passing the meridian in
Greenwich time.
July 2d.
Meridian passage, local time, at 9h. 5m. A.M.
" in Greenwich time 2d. 3h. 1m.
Right ascension same time 56° 42′ 45″
Declination north " 18 00 1
Obliquity of the vortex " 26 2 32
Polar angle " 18 5 7
Arc AQ " 26 51 4
[Illustration: Fig. 14]
PA = 17° 59′ 59″ } P = 128° 37′ 38″
PV = 26 2 32 }
VA = 89 3 0 V = 47 59 44
VQ = 62 11 56 A = 20 3 42
PQ = 47 14 22 Q = 26 22 55
Latitude of Q on the sphere = 42° 45′ 38″
CORRECTION FOR PROTUBERANCE.
We have hitherto considered the earth a perfect sphere with a diameter
of 7,900 miles. It is convenient to regard it thus, and afterwards make
the correction for protuberance. We will now indicate the process for
obtaining this correction by the aid of the following diagram.
[Illustration: Fig. 15]
Let B bisect the chord ZZ′. Then, by geometry, the angle FQY is equal to
the angle BTF, and the protuberance FY is equal the sine of that angle,
making QF radius. This angle, made by the axis of the vortex and the
surface of the sphere, is commonly between 30° and 40°, according as the
moon is near her apogee or perigee; and the correction will be greatest
when the angle is least, as at the apogee. At the equator, the whole
protuberance of the earth is about 13 miles. Multiply this by the cosine
of the angle and divide by the sine, and we shall get the value of the
arc QY for the equator. For the smallest angle, when the correction is a
maximum, this correction will be about 20′ of latitude at the equator;
for other latitudes it is diminished as the squares of the cosines of
the latitude. Then add this amount to the latitude EQ, equal the
latitude EY. This, however, is only correct when the axis of the vortex
is in the same plane as the axis of the earth; it is, therefore, subject
to a minus correction, which can be found by saying, as radius to cosine
of obliquity so is the correction to a fourth--the difference of these
corrections is the maximum minus correction, and needs reducing in the
ratio of radius to the cosine of the angle of the moon's distance from
the node; but as it can only amount to about 2′ at a maximum under the
most favorable circumstances, it is not necessary to notice it. The
correction previously noticed is on the supposition that the earth is
like a sphere having TF for radius; as it is a spheroid, we must correct
again. From the evolute, draw the line SF, and parallel to it, draw TW;
then EW is the latitude of the point F on the surface of the spheroid.
This second correction is also a plus correction, subject to the same
error as the first on account of the obliquity, its maximum value for an
angle of 30° is about 6′, and is greatest in latitude 45°; for other
latitudes, it is equal {6′ × sin(double the lat.)}/R.
The three principal corrections for protuberance may be _estimated_ from
the following table, calculated for every 15° of latitude for an angle
of 30°, or when the correction is greatest.
Latitude. 1st Corr. 2d Corr. 3d Corr.
0 + 20′ + 0 - 2
15 + 19 + 3 - 1.5
30 + 15 + 5 - 1.5
45 + 10 + 6 - 1.
60 + 5 + 5 - 1
70 + 1 + 3 - 0.5
We can now apply this correction to the latitude of the vortex just
found:
Latitude on the sphere 42° 45′ 38″ n.
Correction for protuberance + 14 22
----------
Correct latitude 43 00 00
MILWAUKIE STORM, JULY 2.
As this example was calculated about ten days before the actual date, we
have appended an extract from the Milwaukie papers, which is in the same
longitude as Ottawa, in which place the calculation was made. It is
needless to remark that the latitude of Milwaukie corresponds to the
calculated latitude of the centre of the vortex. It is not intended,
however, to convey the idea that the central line is always the most
subject to the greatest violence--a storm may have several centres or
nuclei of disturbance, which are frequently waning and reviving as the
storm progresses. Generally speaking, however, the greatest action is
developed along the line previously passed over by the axis of the
vortex.
"SUMMIT, Waukesha Co., Wis., July 4, 1853.
"Our town, on Saturday, the 2d, was visited by a terrible storm,
which will long be remembered by those who witnessed its effects and
suffered from its fury. It arose in the south-west, and came
scowling in blackness, sufficient to indicate its anger, for the
space of eighty or a hundred rods in _width_, covering our usually
quiet village; and for nearly half an hour's duration, the rain fell
in torrents, the heavens blazed with the lightning's flashes, trees
fell and were uprooted by the fury of the blast, fragments of gates
and of buildings, shingles, roof-boards, rafters, circled through
the air, the playthings of the wind--and buildings themselves were
moved entire from their foundations, and deposited at different
distances from their original positions. A barn, fifty-five feet
square on the ground, owned by Mr. B. R. Hinckley, is moved from its
position some ten feet to the eastward; and a house, some fifteen by
eighteen feet on the ground, owned by the same person, fronting the
east, was driven by the wind to the opposite side of the street, and
now fronts nearly west; and what is most strange, is that the grass,
in the route the house must have passed over, stands straight as
usual, and gives no evidence that the building was pushed along on
the ground. A lady running from a house unroofed by the storm, took
an aërial flight over two fences, and finally caught against a tree,
which arrested her passage for a moment only, when, giving way, she
renewed her journey for a few rods, and was set down unhurt in
Mr. O. Reed's wheat field, where, clinging to the growing grain, she
remained till the gale went by."[11]
The weather at this place is briefly recorded in the accompanying
abstract from the journal, as well as in an extract from a note to
Professor Henry, of the Smithsonian Institution, from a friend of the
authors, who has long occupied a high official station in Illinois. But
such coincidences are of no value in deciding on the merits of such a
theory, it must be tried before the tribunal of the world, and applied
to phenomena in other countries with success, before its merits can be
fully appreciated. The accompanying record, therefore, is only given to
show how these vortices render themselves apparent, and what ought to be
observed, and also to exhibit the order of their recurrence and their
positions at a given time.
_Extract of a note addressed to the Secretary of the Smithsonian
Institution, by Hon. John Dean Caton, on this subject._
"As a striking instance of the remarkable coincidences confirmatory
of these calculations, I will state, that on Friday, the first of
July last, this gentleman[12] stated that on the next day a storm
would pass north of us, being central a little south of Milwaukie,
and that he thought, from the state of the atmosphere, the storm
would be severe, and that its greatest violence would be felt on the
afternoon or night of the next day. At this time the weather was
fine, without any indications of a storm, so far as I could judge.
At noon on the following day he pointed out the indications of a
storm at the north and north-west, consisting of a dark, hazy belt
in that direction, extending up a few degrees above the horizon,
although so indistinct as to have escaped my observation. At five
o'clock a violent storm visited us, which lasted half an hour,
although a clear sky was visible at the south the whole time. On
Monday morning I learned, from the telegraph office at Chicago, that
early on Saturday afternoon communication with Milwaukie had been
interrupted by atmospheric electricity, and that the line had been
broken by a storm."
NEW YORK STORM.
After this was written, the author discovered that the vortex was
equally violent the day before at New York, July 1st, 1853. An account
of this storm follows. The calculation has not been made, but it is easy
to perceive that the latitude of the vortex, on July 1st, must be very
nearly that of New York--being in latitude 43° next day and ascending.
"At a meeting of the American Association, convened at Cleveland,
Professor Loomis presented a long notice of the terrible hail storm in
New York on the 1st of July. He traced its course, and minutely examined
all the phenomena relating to it, from a mile and a half south-east of
Paterson, N.J., to the east side of Long Island, where it appeared
nearly to have spent its force. It passed over the village of Aqueenac,
striking the Island of New York in the vicinity of the Crystal Palace.
It was not much more than half a mile wide. The size of the hail-stones
was almost incredibly large, many of them being as large as a hen's egg,
and the Professor saw several which he thought as large as his fist.
Some of them weighed nearly half a pound. The principal facts in
relation to this storm were published at the time, and need not be
repeated. The discussions arising among the members as to the origin and
the size of these hail-stones, and the phenomena of the storm, were
exceedingly interesting. They were participated in by Professors Heustus
and Hosford, of Cambridge University, Professor Loomis, and Professors
Bache and Redfield. The latter two gentlemen differ somewhat, we should
suppose radically, in their meteorological theories, and had some very
sharp but very pleasant "shooting" between them."[13]
CENTRAL VORTEX DESCENDING.
We will now make the calculation for the central vortex _descending_,
for longitude 88° 50′ west, August 7, 1853,--putting down the necessary
elements for the time of the meridian passage in order:
Meridian passage in local time at 2h. 25m. P.M.
" " in Greenwich time 7d. 8h. 18m.
Mass of the moon 1/12.3 M. R. V. minor 3,256 miles.
Obliquity of the vortex, same time 26° 5′ 0″
Polar angle of " " 17 41 47
True longitude of moon's node " 78 42 0
" inclination of orbit " 5 5 0
" longitude of the sun " 135 20 0
Moon's longitude " 169 44 0
" distance from node " 91 2 0
" distance from quadrature " 55 36 0
" true semi-diameter " 943
" right ascension " 172 30 0
" declination north " 8 42 20
Constant logarithm 2.889214
Arith. comp. of log. of 943 7.025488
Log. cos. arc. AR 9.914702 = 34° 44′ 48″
1st. correction, + 2 45 0
2d. correction, - 1 14 15
--------------
Corrected arc AQ = 36 15 33
PA = 81° 17′ 40″
PV = 26 5 0
P = 115 11 47
V = 63 34 26
A = 23 28 24
AV = 92 48 39
Q = 31 32 18
Complement of lat. = PQ = 48° 49′ 41″
The latitude is therefore for
the earth, as a sphere 41 10 18
Correction for protuberance + 0 16 0
------------
True latitude of centre 41 26 18 north.
------------
Latitude of Ottowa 41 20 0 "
------------
Vortex passed 6 18 north of Ottowa.
[Illustration: Fig. 16]
As this was nearly a central passage, and as the influence was less
extensive than usual, on account of great atmospheric pressure with a
low dew point, the central disturbance could the more readily be
located, and was certainly to the north, and but a few miles. The
following is from the record of the weather:
_August_ 6th. Very fine and clear all day; wind from S.-W.; a light
breeze; 8 P.M. frequent flashes of lightning in the northern sky;
10 P.M. a _low bank of dense clouds in north_, fringed with cirri,
visible during the flash of the lightning; 12 P.M. same continues.
7th. Very line and clear morning; wind S.-W. moderate; noon, clouds
accumulating in the northern half of the sky; wind fresher S.-W.; 3 P.M.
a clap of thunder overhead, and black cumuli in west, north, and east;
4 P.M. much thunder, and scattered showers; six miles west rained very
heavily; 6 P.M. the heavy clouds passing over to the south; 10 P.M.
clear again in north.
_August_ 8th. Clear all day; wind the same (S.-W.); a hazy bank visible
all along on _southern horizon_.
This was not a storm, in the ordinary acceptation of the term; but the
same cause, under other circumstances, would have produced one; and let
it be borne in mind, that although the moon is the chief disturbing
cause, and the passages of the vortices are the periods of greatest
commotion in both settled and unsettled weather, still the sun is
powerful in predisposing the circumstances, whether favorable or
unfavorable; and as there is no periodic connection between the passage
of a vortex and the concurrence of the great atmospheric waves, it will,
of course, happen only occasionally that all the circumstances will
conspire to make a storm. There are also other modifying causes, to
which we have not yet alluded, which influence the storms at different
seasons of the year,--exaggerating their activity in some latitudes, and
diminishing it in other latitudes. In this latitude, the months of May,
June, and July are marked by more energetic action than August,
September, and October. The activity of one vortex also, in one place,
seems to modify the activity of another vortex in another place. But the
great question to decide is: Do these vortices really exist? Do they
follow each other in the _order_ indicated by the theory? Do they pass
from south to north, and from north to south, at the _times_ indicated
by the theory? Do they obey, in their monthly revolutions, a
mathematical law connecting them with the motions of the moon? We answer
emphatically, Yes! And the non-discovery of these facts, is one of the
most humiliating features of the present age.
OTTOWA STORM, DECEMBER 22, 1852.
To show that the same calculations are applicable for other times, we
will make the calculation for the _centre ascending_, for the 22d
December, 1852, taking the following elements:
Moon's mer. passage, Dec. 22d 15h. 16m. G. time.
" right ascension, same time 51° 57′
" declination north 15 42
" true S. Diameter 886.6″
" distance from node 37
" " " quadrature 52
--------
Which gives the arc AR 29 5
1st correction -1 51
2d +1 11
--------
Corrected arc AQ 28 25
--------
And the latitude at the time of the meridian passage = 42° north, or
about forty miles north of Ottawa.
Abstract from the record:--
[14]_Dec._ 21st, 1852. Wind N.-E., fine
weather.
_Dec._ 22d. Thick, hazy morning, wind east, much lighter in S.-E. than
in N.-W.; 8 A.M., a clear arch in S.-E. getting more to south; noon,
very black in W. N.-W.; above, a broken layer of cir. cumulus, the sun
visible sometimes through the waves; wind round to S.-E., and fresher;
getting thicker all day; 10 P.M., wind south, strong; thunder,
lightning, and heavy rain all night, with strong squalls from south.
_Dec._ 23d. Wind S.-W., moderate, drizzly day; 10 P.M., wind west, and
getting clearer.
The next day the vortex passed the latitude of Montreal (the moon being
on the meridian about 10 P.M.)
MAGNETIC STORM, DECEMBER 23, 1852.
In the July number of Vol. XVI. of Silliman's Journal, we find certain
notices of the weather in 1852, by Charles Smallwood, of St. Martins,
nine miles east of Montreal. He mentions "two remarkable electrical
storms (which) occurred on the 23d and 31st of December, (in which)
sparks 5/40 of an inch were constantly passing from the conductor to the
discharger for several hours each day." At 10 P.M. (23d) the vortex
passed over Montreal, and again descending on the 31st North, and was
visible at Ottowa on the morning of the 1st of January, with southerly
wind setting towards it. On the 29th of December, Mr. Smallwood records
"a low auroral arch, sky clear." On the 20th, the vortex was 5° to the
northward of Montreal, and the aurora was consequently low--the
brightest auroras being when the vortex is immediately north without
storm, or one day to the northward, although we have seen it _very low_
when the vortex was three days to the north, and no other vortex near.
LIVERPOOL STORM.
On the night of the 24th of December, the same central vortex ascending
passed between Cape Clear and Liverpool.
On the 25th, at midnight, the vortex passed to the north of Liverpool:
its northerly progress being very slow, being confined for three days
between the parallel of Liverpool and its extreme northern limit in
latitude about 57°. The accompanying account of the weather will show
the result of a long-continued disturbance near the same latitude:
The Baltic, three days out from Liverpool, encountered the vortex on the
night of the 23d. On the morning of the 25th, very early, the gale
commenced at Liverpool, and did much damage. On the 26th, the vortex
attained its northern limit; but we have not been able to procure any
account of its effects to the northward of Liverpool, although there can
be but little doubt that it was violent on the coast of Scotland on the
26th; for the next day (27th) the vortex having made the turn, was near
the latitude of Liverpool, and caused a _tremendous_ storm, thus showing
a continued state of activity for several days, or a peculiarly
favorable local atmosphere in those parts. It is very probable, also,
that there was a conjunction of the central and inner vortex on the
27th. The inner vortex precedes the central in passing latitude 41°; but
as the mean radius of its orbit is less than that of the central, it
attains to a higher latitude, and has, consequently, to cross the path
of the central, in order again to precede it descending in latitude 41°.
As a very trifling change in the elements of the problem will cause
great changes in the positions of the vortices on the surface of the
earth, it cannot now be asserted that such a conjunction did positively
occur at that time; but, it maybe suspected, that a double disturbance
would produce a greater commotion, or, in other words, a more violent,
storm.
It is on this account, combined with other auxiliary causes, that the
vicinity of Cape Horn is so proverbially stormy, as well as for the low
standard of the barometer in that latitude, it is the stationary point
of the vortices in ordinary positions of the nodes and perigee of the
moon. We have already alluded to the fact, that none of the vortices
scarcely ever pass much beyond latitude 80°, and then only under
favorable circumstances, so that we ought to infer, that gales in high
latitudes should set from the poles towards the storms in lower
latitudes. This is, no doubt, the fact, but, nevertheless, a hard
southerly blow _may possibly_ occur in high northern latitudes, if a
storm should be raging very violently in a lower latitude on the
opposite side of the pole, the distance across the circle of 80° being
only about 1,400 miles. As the different vortices have a different limit
in latitude every year, the determination of this turning point is
obviously of great practical utility, as the fact may yet be connected
with other phenomena, so as to give us the probable character of the
polar ice at any assigned time. On this point we have more to say.
PASSAGES OF ALL THE VORTICES.
Our remarks have hitherto been confined to the central vortex. We shall
now show from the record, that the other vortices are as effective in
deranging the equilibrium of our atmosphere. In the following table we
have given the passages of the different vortices, which will serve as
their true positions within moderate limits, to calculate from, for all
future time.
PASSAGES OF THE CENTRAL AND LATERAL VORTICES, OBSERVED IN JUNE AND JULY,
1853, IN LATITUDE 41° 20′ NORTH.
I signifying Inner; O, outer; C, central; A, ascending; D, descending.
____________________________________________________________________
| | | | | | |
| Order.|Vortex.| Date. | Meridian |Passage.| Calculated latitude |
| | | | Passage. | | and Remarks. |
|_______|_______|_________|__________|________|______________________|
| | | | | | |
| 1st | I. A. | June 22 | 7 A.M. | south | Centre. About 40°. |
| | | 23 | 8 A.M. | north | Warsaw. Storm. |
| 2d | O. D. | 27 | 0 noon | north | |
| | | 28 | 1 A.M. | south | See record. |
| 3d | C. A. | July 1 | 9 A.M. | south | |
| | | 2 | 10 A.M. | north | Lat. 43°. Storm. |
| 4th | I. D. | 7 | 5 P.M. | north | |
| | | 8 | 6 P.M. | south | Lat. New York. Storm.|
| 5th | C. D. | 12 | 5 P.M. | north | Aurora. |
| | | 13 | 6 P.M. | south | Stormy, very. |
| 6th | O. A. | 14 | 10 A.M. | south | |
| | | 15 | 11 A.M. | north | See Record. |
|_______|_______|_________|__________|________|______________________|
The intervals between the ascending and descending passages of the
different vortices, are
Between I. A. and I. D. from 11 to 14 days.
" O. A. " O. D. " 10 " 12 "
" C. A. " C. D. " 9 " 11 "
and the effect is greatest when the vortex comes to the meridian before
the sun, and least when after the sun; in which case the full effect is
not developed, sometimes until the following day.
A brief abstract from a journal of the weather for one sidereal period
of the moon, in 1853.
_June_ 21st. Fine clear morning (S. fresh)[15]: noon very warm 88°;
4 P.M. plumous _cirri in south_; ends clear.
22d. Hazy morning (S. very fresh) arch of cirrus in west; 2 P.M., black
in W.-N.-W.; 3 P.M., overcast and rainy; 4 P.M., a heavy gust from
south; 4.30 P.M., blowing furiously (S. by W.); 5 P.M., tremendous
squall, uprooting trees and scattering chimneys; 6 P.M., more moderate
(W.)
23d. Clearing up (N.-W.); 8 A.M., quite clear; 11 A.M., bands of mottled
cirri pointing N.-E. and S.-W.; ends cold (W. N.-W.); the cirri seem to
rotate from left to right, or with the sun.
24th. Fine clear cool day, begins and ends (N.-W.)
25th. Clear morning (N.-W, light); 2 P.M. (E.) calm; tufts of tangled
cirri in north intermixed with radiating streaks, all passing eastward;
ends clear.
26th. Hazy morning (S.-E) cloudy; noon, a heavy windy looking bank in
north (S. fresh), with dense cirrus fringe above on its upper edge;
clear in S.
27th. Clear, warm, (W.); bank in north; noon bank covered all the
northern sky, and fresh breeze; 10 P.M., a few flashes to the northward.
28th. Uniform dense cirro-stratus, (S. fresh); noon showers all round;
2 P.M., a heavy squall of wind, with thunder and rain (S.-W. to N.-W.);
8 P.M., a line of heavy cumuli in south; 8.30 P.M., a very bright and
high cumulus in S.-W., protruding through a layer of dark stratus;
8.50 P.M., the cloud bearing E. by S., with three rays of electric
light.[16]
[Illustration: Fig. 17]
_June_ 29th. A stationary stratus over all, (S.-W. light); clear at
night, but distant lightning in S.
30th. Stratus clouds (N.-E. almost calm); 8 A.M., raining gently;
3 P.M., stratus passing off to S; 8 P.M., clear, pleasant.
_July_ 1st. Fine and clear; 8 A.M., cirrus in sheets, curls, wisps, and
gauzy wreathes, with patches beneath of darker shade, all nearly
motionless; close and warm (N.-E.); a long, low bank of haze in S., with
one large cumulus in S.-W., but very distant.
_July_ 2d. At 5 A.M., overcast generally with hazy clouds and fog of
prismatic shades, chiefly greenish-yellow; 7 A.M., (S.-S.-E.
freshening,) thick in W; 8 A.M., (S. fresh) much cirrus, thick and
gloomy; 9 A.M., a clap of thunder, and clouds hurrying to N.; a reddish
haze all around; at noon the margin of a line of yellowish-red cumuli
just visible above a gloomy-looking bank of haze in N.-N.-W., (S. very
fresh;) warm, 86°; more cumuli in N.-W.--the whole line of cumuli N. are
separated from the clouds south by a clear space. These clouds are borne
rapidly past the zenith, but never get into the clear space--they seem
to melt or to be turned off N.-E. The cumuli in N. and N.-W., slowly
spreading E. and S.; 3 P.M., the bank hidden by small cumuli; 4 P.M.,
very thick in north, magnificent cumuli visible sometimes through the
breaks, and beyond them a dark, watery back-ground, (S. strong);
4.30 P.M., wind round to N.-W. in a severe squall; 5 P.M., heavy rain,
with thunder, &c.--all this time there is a bright sky in the south
visible through the rain 15° high; 7 P.M., clearing, (S.-W. mod.)
_July_ 3d. Very fine and clear, (N.-W.); noon, a line of large cumuli in
N., and dark lines of stratus below, the cumuli moving eastward; 6 P.M.,
their altitude 2° 40′. Velocity 1° per minute; 9 P.M., much lightning in
the bank north.[17]
_July_ 4th. 6 A.M., a line of small cumulo-stratus, extending east and
west, with a clear horizon north and south 10° high. This band[18] seems
to have been thrown off by the central yesterday, as it moves slowly
south, preserving its parallelism, although the clouds composing it move
eastward. Fine and cool all day--(N.-W. mod.)--Lightning in N.
_July_ 5th. Cloudy (N. almost calm), thick in E., clear in W.; same all
day.
6th. Fine and clear (E. light); small cumuli at noon; clear night.
7th. Warm (S. E. light); cirrus bank N. W.; noon (S.) thickening in N.;
6 P.M., hazy but fine; 8 P.M., lightning in N.; 10 P.M., the lightning
shows a heavy line of cumuli along the northern horizon; calm and very
dark and incessant lightning in N.
8th. Last night after midnight commencing raining, slowly and steadily,
but leaving a line of lighter sky south; much lightning all night, but
little thunder.
8th. 6 A.M. Very low scud (500 feet high) driving south, still calm
below, (N. light); 10 A.M., clearing a little; a bank north with cirrus
spreading south; same all day; 9 P.M., wind freshening (N. stormy);
heavy cumuli visible in S.; 10.30 P.M., quite clear, but a dense watery
haze obscuring the stars; 12 P.M., again overcast: much lightning in S.
and N.-W.
9th. Last night (2 A.M. of 9th) squall from N.-W. very black; 4 A.M.,
still raining and blowing hard, the sky a perfect blaze, but very few
flashes reach the ground; 7 A.M., raining hard; 8 A.M. (N.-W. strong); a
constant roll of thunder; noon (N.-E.); 2 P.M. (N.); 4 P.M. clearing;
8 P.M., a line of heavy cumuli in S., but clear in N-W., N., and
N.-E.[19]
NEW YORK STORM, JULY 8, 1853.
"At 5 o'clock Friday afternoon, a terrible storm of rain, hail, and
lightning, rose suddenly from the north-west, and passed over the upper
part of the city and neighborhood. It was quite moderate in the lower
part of the town, and probably scarcely felt on Staten Island. The whole
affair lasted not more than a quarter of an hour, yet the results were
most disastrous, as will be seen by the following accounts from our
reporters:
"Happening to be in the neighborhood of the Palace about 5 o'clock
Friday evening, we sought shelter under its ample roof from an impending
thunder storm, of very threatening appearance, rapidly approaching from
the west. We had scarcely passed the northern entrance, and reached the
gallery by the nearest flight of steps, when the torrent--it was not
rain, but an avalanche of water--struck the building; the gutters were
filled on the windward side in a moment, and poured over an almost
unbroken sheet of water, which was driven through the Venetian blind
ventilators, into and half way across the north-west gallery, and also
through the upper ventilators, falling upon the main floor of the north
transept. Workmen hastened to close the blinds, but that did not prevent
the deluge. The tinning of the dome being unfinished, the water, of
course, came down in showers all over the centre. Many workmen were
engaged on the dome when the shower struck it; several of them, in their
haste to escape such dangerous proximity to the terrific lightning, came
down single ropes, hand over hand. Large number of workmen were engaged
all over the exterior, and such a scampering will rarely be witnessed
but once in a lifetime. It was found impossible to close a north window,
used for ingress and egress of workmen upon the rod, and the water came
in, in almost solid columns. For a time the water was nearly two inches
deep on the gallery floor, and poured down the stairs in miniature
cascades.
"A great number of boxes, bales, and packages of goods lay upon the main
floor, among which the water poured down from the edge of the gallery
floor in destructive quantities; Fortunately but few goods were opened,
and were upon the tables, or the damage would have been irreparable. As
it is, we fear some of the goods are injured. In the height of the
storm, the centre portion of the fanlight over the western entrance
burst in, and several single lights were broken, by staging or
otherwise.
"About ten minutes after the storm burst, the most terrific hailstorm we
ever saw began to rattle, like discharges of musketry, upon the tin roof
and glass sides. Some of the masses of ice were as large as hen's eggs.
There were probably a thousand excited workmen in the building, and a
good many exhibitors and visitors, among whom there were some twenty
ladies, some of whom appeared a good deal alarmed at the awful din. A
portion of the frame-work of the addition next to 42d street, went down
with a terrible crash, and a part of the brick wall of the engine-house
on the opposite side of the street, was blown over, crushing two or
three shanties, fortunately without any other injury than driving the
occupants out into the storm. But an awful scene occurred on the north
side of 43d street, directly opposite the Latting Tower. Here two large
unfinished frame buildings were blown, or rather, we should judge from
appearances, were crushed down into a mass of ruins, such as may be
imagined by supposing a great weight had fallen, with a circular,
grinding motion, upon the first fine fabrics. One of them was partly
sided, and had the rafters up, but no roof; the other was sided and
rooted with tin, and was being plastered. We were told it was three
stories high, 50 by 98 feet.
"We reached the ruins among the first, after the burst of the storm
subsided a little. The scene was such as we pray God we may never
witness again. A small portion of the roof and upper part of the front
of the building stood or rather partly hung over the side-walk. The
chamber and lower floor of the front rooms lay flat together. The sides
were standing. In the rear all were down. In this building, besides the
workmen, there were numerous laborers who had taken shelter under its
roof when the storm drove them hurriedly from their work. How so many
persons escaped death is truly wonderful. It can only be accounted for
by supposing that they had a moment's warning, and rushed into the
street. The first alarm was from the tearing off a portion of the tin
roof, which was carried high over another building, and fell in the
street. A horse and cart barely escaped being buried under this. It
seems the frame of the other building came down with a deafening crash
at the same time, confusing instead of warning those in danger. At any
rate, before they could escape, they were buried in a mass of timber,
and three of them instantly killed, and four or five dangerously
wounded; and others slightly bruised and badly frightened. Several would
have perished but for timely assistance to extricate them. In this they
were greatly assisted by Jacob Steinant, boss carpenter of the Tower,
who with his men rushed to the rescue, notwithstanding the pouring down
torrents.
"In Williamsburgh, the storm lasted about fifteen minutes, doing an
incalculable amount of damage to dwellings, foliage, &c. Hailstones came
down in sizes from that of a hickory-nut to a large apple, some with
such force as to drive them through the cloth awnings.
"The storm passed over Brooklyn lightly, in comparison with the effects
across the Williamsburgh line. On Flushing avenue, beyond the Naval
Hospital, a number of trees were uprooted, and the window-panes of the
houses shattered. On the corner of Fulton and Portland avenues, three
buildings were unroofed, and the walls of the houses were sprung to the
foundation.
"On Spencer street, a new frame building was levelled with the ground.
Along Myrtle, Classon, and other streets and avenues of East Brooklyn,
many of the shade trees were uprooted, and the windows smashed. In Jay
street, two trees were struck by lightning, but no other damage ensued.
"Several schooners at the foot of Jay street were forced from their
moorings, but were soon after secured. A small frame house in Spencer
street, just put under roof, was prostrated to the ground.
"We understand that a large barn filled with hay, situated on the road
between Bushwick and Flushing, was struck by lightning and destroyed
with its contents, embracing several head of live stock."[20]
_July_ 10th, 3 A.M. Overcast and much lightning in south (N. mod.);
7 A.M., clear except in south; 6 P.M. (E.); 10 P.M., lightning south;
11 P.M., auroral rays long but faint, converging to a point between
Epsilon Virginis and Denebola, in west; low down in west thick with
haze; on the north the rays converged to a point still lower; lightning
still visible in south. This is an aurora in the west.
11th. Fine clear morning (N.-E.); same all day; no lightning visible
to-night, but a bank of clouds low down in south, 2° high, and streaks
of dark stratus below the upper margin.
12th. Fine and clear (N.-E.); noon, a well defined arch in S.-W., rising
slowly; the bank yellowish, with prismatic shades of greenish yellow on
its borders. This is the O. A. At 6 P.M., the bank spreading to the
northward. At 9 P.M., thick bank of haze in north, with bright auroral
margin; one heavy pyramid of light passed through Cassiopæa, travelling
_westward_ 1½° per minute. This moves to the other side of the pole,
but not more inclined towards it than is due to prospective, if the
shaft is very long; 11.10 P.M., saw a mass of light more diffuse due
east, reaching to _Markab_, then on the prime vertical. It appears
evident this is seen in profile, as it inclines downwards at an angle of
10° or 12° from the perpendicular. It does not seem very distant.
12 P.M., the aurora still bright, but the brightest part is now west of
the pole, before it was east.
13th, 6 A.M. Clear, east and north; bank of cirrus in N.-W., _i.e._,
from N.-N.-E. to W. by S.; irregular branches of cirrus clouds, reaching
almost to south-eastern horizon; wind changed (S.-E. fresh); 8 A.M., the
sky a perfect picture; heavy regular shafts of dense cirrus radiating
all around, and diverging from a thick nucleus in north-west, the spaces
between being of clear blue sky. The shafts are rotating from north to
south, the nucleus advancing eastward.
Appearance of the central vortex descending at 8 A.M., July 13th, 1853:
In Fig. 18, the circle represents the whole sky from the zenith to the
horizon, yet it can convey but a very faint idea of the regularity and
vividness of this display. The reflected image of the sky was received
from a vessel of turbid water, which will be found better than a mirror,
when the wind will permit.
[Illustration: Fig. 18]
At noon (same day) getting thicker (S.-E. very fresh); 6 P.M., moon on
meridian, a prismatic gloom in south, and very thick stratus of all
shades; 9 P.M., very gloomy; wind stronger (S.-E.): 10 P.M., very black
in south, and overcast generally.
14th. Last night about 12 P.M. commenced raining; 3 A.M., rained
steadily; 7 A.M., same weather; 8.20 A.M., a line of low storm-cloud, or
seud, showing very sharp and white on the dark back ground all along the
southern sky. This line continues until noon about 10° at the highest,
showing the northern boundary of the storm to the southward; 8 P.M.,
same bank visible, although in rapid motion eastward; same time clear
overhead, with cirrus fringe pointing north from the bank; much
lightning in south (W. fresh); so ends.
15th. Last night a black squall from N.-W. passed south without rain; at
3 A.M. clear above, but very black in south (calm below all the time);
9 A.M., the bank in south again throwing off rays of cirri in a
well-defined arch, whose vortex is south: these pass east, but continue
to form and preserve their linear direction to the north; no lightning
in south to-night.
16th. Clear all day, without a stain, and calm.
17th. Fine and clear (N.-E. light); 6 P.M., calm.
18th. Fair and cloudy (N.-E. light); 6 P.M., calm.
19th. Fine and clear (N. fresh); I. V. visible in S.-W.
20th. 8 A.M., bank in N.-W. with beautiful cirrus radiations; 10 A.M.,
getting thick with dense plates of cream-colored cirrus visible through
the breaks; gloomy looking all day (N.-E. light).[21]
Appearance of the Inner Vortex at 8 A.M., July 20th, 1853, including the
whole sky. (See Fig. 19.)
[Illustration: Fig. 19]
This was a different passage of the Inner Vortex ascending as compared
with the same 28 days before. At that date (June 22) it did great damage
in the central parts of Illinois. Still this last passage was very
palpable--the clouds were very irregularly assorted--plates of cirrus
above and beneath cumulus--various kinds of cirrus clouds, and that
peculiar prismatic haze which is a common sign of the passage of a
vortex. The appearance depicted above is a very common, although a very
evanescent appearance. When the sky appears of a clear blue through the
cirri, there will be generally fresh gales without any great electrical
derangement; but if the clear spaces are hazy, gradually thickening
towards the nucleus, a storm may be expected. Any one who wishes to
understand the indications of the clouds, must watch them closely for
many years, before he can place much reliance upon them. But we shall
again advert to this point.
We have now passed through one sidereal period of the moon. We might
continue the record, but it would be tedious. The passages of these
vortices vary in violence at different times, as we might expect; but
they never cease to circulate, and never will as long as the moon
remains a satellite to the earth; and if we take the passage of any of
these vortices, and add thereto the time of one sidereal period of the
moon, we get approximately the time of the next passage. When the
elements of the lunar orbit tend to accelerate the passages, they may
come in 26 days; and when to retard, in 28 days; and these are about the
limits of the theory.
Having begun and ended this record of the weather with the passage of
the Inner vortex ascending, it may not be amiss to notice one more, (the
August passage,) as it offers a peculiarity not often so distinctly
marked. We have alluded to the greater force of the storms when the
passage of the vortex corresponds to the passage of the line of low
barometer or the depression point of a great atmospheric wave, which is
also due to the action of the ether. In consequence of these waves
passing from west to east, the storm will only be violent when formed a
little to the westward. If the storm forms to the eastward, we neither
see it nor feel it, as it requires time to develop its strength, and
always in this latitude travels eastward; so that storms may generally
be said to come from the west, although the exciting cause travels from
east to west. In the case now alluded to, the weather indicated a high
barometer, and the storm formed immediately to the eastward, even
showing a distinct circular outline. We subjoin a description.
_August_ 15th. Clear morning (N.-E.), a bank of cumuli in south: noon
quite cloudy in S. and clear in north. (N.-E.)
16th. Clear morning (N.-E.); 3 P.M., getting very black in E. and S.-E.,
very _clear_ to the _westward_; 4 P.M., much thunder and lightning in
east, and evidently raining hard; 5 P.M., a violent squall from _east_
for 10 minutes; tore up several trees; 6 P.M., the storm passing
eastward, clear in west all this time; 6.30 P.M., the storm forming a
regular arch, the vertex being in _S.-E._; the arch of hazy cirrus and
heavy cumulus much lower in S.-E., wind still moderate from east;
10 P.M., clear all around, but lightning in S.-E. and E.
17th. Fine clear morning (W.); noon, scattered cumuli in north; 6 P.M.,
a beautifully regular arch of dense cumuli and cirrus margin in _N.-E._,
with a constant glimmer of lightning; 7 P.M., very clear to the west,
and north-west, and south; along the northern horizon a line of high
peaked cumuli terminating in N.-N.-W.; a continued roll of distant
thunder in the circular bank in N.-E., and not a moment's cessation to
the lightning; the electric excitement advancing westward along the
lines of cumuli; the cirrus haze also rising and passing towards S.-W.;
8 P.M., the sky alive with lightning, the cirrus now reaches the zenith;
no streaks of lightning coming to the earth; they seem to radiate from
the heaviest mass of cumuli, and spread slowly (sufficiently so to
follow them) in innumerable fibres over the cloudy cirrus portion of the
sky; every flash seems to originate in the same cloud; 8.30 P.M., one
branching flash covered the whole north-eastern half of the sky, no
leafless tree of the forest could show so many branches; 9.30 P.M., all
passed to S.-W. without rain, leaving behind a large cumulus, as if it
lagged behind. From this cumulus a straight line of lightning shot up
10° above the cloud into a perfectly clear sky, and terminated abruptly
without branching.
We have been thus particular in giving these details, as this was a
clear case confirming the principles advanced, that the vortices do not
form a continuous line of disturbance, in their daily passage around the
earth. It shows also that the barometer, in connection with these
principles, will be a far more useful instrument than it has yet proved
itself, for practical service as an indicator of the weather.
FOOTNOTES:
[10] For convenience to those wishing to verify the calculation of these
triangles, we have put down each side and angle as found. Also, as an
aid to the navigator.
[11] Daily Wisconsin, July 7.
[12] The author.
[13] Chicago Democrat.
[14] This was also calculated before the event.
[15] The letters in a parenthesis signify the direction of the wind.
[16] Giving this cloud the average velocity of thirty miles per hour,
its altitude was determined by the sextant at twelve miles, and we think
under-estimated. While measuring, the author's attention was drawn to
the fact, that although it appeared equally dense above and below, yet
its middle part was the brightest, and as there was only a faint glimmer
of twilight in the N.-W., he concluded that the cloud was self-luminous;
for when the smallest stars were visible, it glowed about as bright as
the milky-way in Sagittarius. Occasionally the whole cloud was lit up
internally by the lightning, and about this time it sent off three rays:
one horizontally, westward, which was the faintest; one about N.-W.,
towards Jupiter, and the brightest of the three; and another towards the
north. These were not cirrus streaks, but veritable streams of electric
matter, and had a very decided rotation from left to right, and
continued visible about twenty minutes, as represented above.
[17] This day the central vortex passed in about latitude 47° N.--the
southern margin cannot be nearer than 250 miles, throwing off the 40′
for the horizontal refraction, would give eight miles of altitude above
a tangential plane. Then another seven miles, for curvature, will give
an altitude of fifteen miles for the cumuli. The height of these
thunder-clouds has been much under-estimated. They seem to rise in
unbroken folds to a height of ten and twelve miles frequently; from the
data afforded by the theory, we believe they will be found much higher
sometimes--even as much as sixteen miles.
[18] These parallel bands, and bands lying east and west, are frequent
in fine weather between two vortices. Sailors consider them a sign of
settled weather. After dark there was frequently seen along the northern
horizon flashes of lightning in a perfectly clear sky. But they were
both faint and low, not reaching more than 4° or 5° above the horizon.
After sunset there were very distinct rays proceeding from the sun, but
they were shorter than on the evening of the 3d. These are caused by the
tops of the great cumuli of the storm, when sunk below the horizon,
intercepting the sun's rays, which still shine on the upper atmosphere.
The gradation was very marked, and accorded with the different distances
of the central vortex on the 3d and 4th--although, on the 4th, the
nearest distance must have been over four hundred miles to the southern
boundary of the storm.
[19] It is worthy of notice here, that New York, which only differs by
about 40 miles of latitude and 800 in longitude, had the storm earlier,
near the time of the passage, as appears by the appended account of it.
This proves, that a storm affects a particular latitude simultaneously,
or approximately so. If this had to travel eastward to reach New York,
it would have been the 10th instead of the 8th. The principal trouble
was, however, in the early part of the evening of the 8th, to the south
of Ottawa, where the strong wind was drawn in from the northward. If a
vortex passes from north to south, leaving the observer between the
passages, there must, nearly always, be a winding up squall from the
north to clear away the vapory atmosphere.
[20] From the _New York Tribune_, July 9, 1853.
[21] These pages are now in the compositors' hands, (Nov. 21st,) and up
to the last moment the Author has observed carefully in New York the
passages of these vortices. October 24th, in the inner vortex descending
produced a violent storm on the coast, and much damage ensued. November
7th, the same vortex ascending was also severe. And on November 13th,
early, the passage of the central vortex ascending, caused a flood in
Connecticut of a very disastrous nature. Would it not pay the insurance
offices to patronize such investigations in view of such palpable facts
as these?
SECTION THIRD.
OBJECTIONS TO LUNAR INFLUENCE.
We have now presented a theory of the weather, which accounts for many
prominent phenomena, a few of which we shall enumerate. It is an
observed fact, that in all great storms electrical action is more or
less violent, and that without this element it seems impossible to
explain the velocity of the wind in the tornado, its limited track, and
the formation of large masses of ice or hail in the upper regions of the
atmosphere. It is also an observed fact, that the barometer is in
continued motion, which can only be legitimately referred to a change in
the weight of the atmospheric column. This we have explained as due to
atmospheric waves, caused by the greater velocity of rotation of the
external ether, as well as to the action of the three great vortices.
These causes, however, only partially produce the effect--the greater
portion of the daily oscillations is produced by the action of the great
radial stream of the solar vortex, as we shall presently explain. It is
an observed fact, that, although the storm is frequently violent,
according to the depression of the barometer, it is not always so.
According to the theory, the storm will be violent, _ceteris paribus_,
on a line of low barometer, but may still be violent, when the contrary
obtains. Another fact is the disturbance of the magnetic needle during a
storm. Storms are also preceded generally by a rise in the thermometer,
and succeeded by a fall; also by a fall in the barometer, and succeded
by a rise. It is also well known, that hurricanes are unknown at the
equator, and probably at the poles also. At all events, they are rare in
lat. 80°, and, according to Capt. Scoresby, storms are there frequently
raging to the south, while above, there is clear sky and fine weather,
with a stiff breeze from the northward. The greater violence of storms
in those regions where the magnetic intensity is greater in the same
latitude, the probable connection of peculiarities in the electric state
of the atmosphere with earthquakes, and the indications of the latter
afforded by the magnet; the preponderance of westerly winds at a great
elevation in every latitude on the globe visited by man; and the
frequent superposition of warm layers of air above cold ones at those
elevations, are all facts worthy of note. And the connection of cirrus
clouds with storms, as well as with the aurora, indicates that the
producing cause is external to the atmosphere, and gradually penetrates
below. The theory fully explains this, and is confirmed by the fantastic
wreathings and rapid formation of these clouds in straight lines of a
hundred miles and upwards. But time would fail us in pointing out a
tithe of the phenomena, traceable to the same cause, which keeps our
atmosphere in a perpetual state of change, and we shall only advert to
one more peculiarity of the theory. It places meteorology on a
mathematical basis, and explains why it is that a storm may be raging at
one place, while in another, not very remote, the weather may be fine,
and yet be dependent on the position of the moon.
That the moon has exerted an influence on the weather has been the
popular creed from time immemorial; but, ignorant of the mode in which
this influence was exerted, men have often been found who have fostered
the popular belief for their own vanity or advantage; and, on the other
hand, philosophers have assailed it more by ridicule than by argument,
as a relic of a barbarian age. Not so with all; for we believe we are
not wrong in stating, that the celebrated Olbers compared the moon's
positions with the weather for fifty years, before he gave his verdict
against it. He found the average amount of rain at the perigee about
equal to the amount at the apogee, as much at the full as at the change,
and no difference at the quadratures. But this fact does not throw a
feather in the scale by which this theory is weighed. Popular opinions,
of remote origin, have almost always some foundation in fact, and it is
not much more wise to reject them, than to receive them. The Baron Von
Humboldt--a man possessing that rare ingredient of learning, a practical
common sense--observes: "That arrogant spirit of incredulity which
rejects facts, without attempting to investigate them, is, in some
cases, more injurious than an unquestioning credulity."[22] If a popular
belief or prejudice be absurd, its traditional preservation for a
thousand years or more may very well account for the absurdity.
The present system of astronomy still retains the motley garniture of
the celestial sphere, as handed down from the most remote antiquity; and
granting that ages of ignorance and superstition have involved the
history of the different constellations in a chaos of contradictory
traditions, there is no doubt at the foundation some seeds of truth
which may even yet emerge from the rubbish of fable, and bear fruit most
precious. That the zodial[23] signs are significant records of something
worthy of being preserved, is prejudice to deny; and we must be allowed
to regard the Gorgons and Hydras of the skies as interesting problems
yet unsolved, as well as to consider that the belief in lunar influence
is a fragment of a true system of natural philosophy which has become
more and more debased in postdiluvian times. Amongst those who have not
summarily ignored the influence of the moon, is Toaldo, a Spanish
physicist, who endeavored to show the connection between the recurrence
of warm and cold seasons, and the semi-revolution of the lunar nodes and
apogee, and proposed six of those periods, or about fifty-four years, as
the cycle in which the changes of the weather would run through their
course. According to the present theory, it is not likely such a cycle
will ever be discovered. There are too many secular, as well as periodic
influences combining, to produce the effect; and the times are too
incommensurable. Lately, Mr. Glaisher has presented a paper to the Royal
Society, giving about fourteen years from observation. Others have
lately attempted to connect the changes of the seasons with the solar
spots, as well as with the variations of the magnetism of the earth, but
without any marked result.
It may, however, be urged, that if the sidereal period of the moon be
approximately a cycle of change, it would have been detected long ago.
One reason why this has been so long concealed, is the high latitude of
the observers. Spain, Italy, and Turkey, are better situated than other
European countries; but the scientific nations lie further north; and
from these the law has gone forth to regulate more southern lands. In
the United States, particularly in the great plains of the west, the
weather can be better compared; not only on account of the latitude
being more favorable, but also on account of the greater magnetic
intensity of the western hemisphere.
It must also be remembered that there are in latitude 40°, five or six
distinct passages of the disturbing cause in one sidereal period of the
moon. If two of these periods are drawn closer together by the change of
the elements, the interval between two others must necessarily be
increased. Besides, the effect produced is not always the same, for
reasons already adverted to. One vortex may be more violent one month,
or for a few days in one month, while another may be more active the
next. It may also happen that for several successive passages, the
passage shall be central in one latitude, while two or three degrees
north or south, another place shall be passed by. In different months
and in different years, as well as in different seasons of the year, the
energy of the ether may be augmented or diminished. But it may be said,
that, supposing the theory true, if its indications are so uncertain, it
is of little value. By no means. It is true there are many things to be
inquired into; but it is a great thing in this science to be able to
take the first step in the right direction,--to find even the _key_ of
the portal. It is a great stride to be able to say, a storm may happen
at such a time, but cannot happen at another; that a storm, when raging,
will go in this direction, rather than in that; that it will be central
here, and less violent yonder; and when we consider its bearing on
astronomical and other science, it is difficult to exaggerate its value
to the world at large.
Again, it may be said that rain, and cloudy days, and fresh breezes, and
even strong winds, sometimes occur, when the vortices do not pass
centrally. This is true; yet only indicating that where the vortices are
central, an unusual disturbance is taking place. But there is another
cause, which was purposely omitted in considering the prominent features
of the theory, in order not to encumber the question with secondary
influences. By referring to Fig. 3, section 1, we see that the lateral
vortices of the globe are continually passing off to the southward, in
the northern hemisphere, in a succession of dimples, and continually
reforming. We will now represent this mode of action in profile, as it
actually occurs in the illustration we have used.
The vortex passing off from O, (Fig. 20,) although it does not actually
reach the surface of the atmosphere, affects the equilibrium of the
ether, and, for a short distance from the parent vortex, may cause an
ascensional movement of the air. If to this is conjoined a northerly
wind from the vortex, a band of clouds will be produced, and perhaps
rain; but violent storms never occur in the intervals, except as a
steady gale, caused by the violence of a distant storm. Thus, it will
frequently be noticed that these vortices are flanked by bands of
clouds, which pass southward, although the individual clouds may be
moving eastward. Hence, instead of disproving the theory, they offer
strong evidence of its truth; and could we view the earth from the moon
with a telescope, we should no doubt see her beautifully belted.
[Illustration: Fig. 20]
But it may be again asked, why should not the weather be the same
generally, in the same latitude, if this theory be true? If the earth
were a globe of level land, or altogether of water, no doubt it would be
similar; but it must be remembered, that both land and water are very
unequally distributed: that the land is of varying extent and
elevation--here a vast plain, far removed from the ocean, and there a
mountain chain, interposing a barrier to the free course of the
atmospheric currents; sometimes penetrating in full width into the
frigid zone, and again dwindling to a few miles under the equator. One
very important distinction is also to be remarked, in the superficial
area of the different zones, reckoning from the equator, and taking the
hemisphere as 100 parts:
Frigid zone 8 parts.
Temperate " 52 "
Torrid " 40 "
For as the time of rotation in every latitude is the same, the area to
be disturbed in the same time, is less in high latitudes, and there a
greater similarity will obtain, _ceteris paribus_. In lower latitudes,
where both land and water stretch away for thousands of miles, it is not
wonderful that great differences should exist in the electrical and
hygrometric state of the air.
The summer of many countries is always dry--California for instance. In
winter, in the same country, the rains are apparently incessant. This of
course depends on the power of the sun, in diverting the great annual
currents of the atmosphere. As long as the dry north-west trade sets
down the coast of California, the circumstances are not favorable for
giving full development to the action of the vortices. When the trade
wind ceases, and the prevailing winds come from the south, loaded with
vapor, the vortices produce storms of any magnitude; but (and we speak
from two years' observation) the passages of the vortices are as
distinctly marked there in winter time, as they are in the eastern
States; and in summer time, also, they are very perceptible. The same
remark applies to Mediterranean countries, particularly to Syria and
Asia Minor; although the author's opportunity for observing lasted only
from April to December, during one season. If we are told it never rains
on the coast of Peru, or in Upper Egypt, it does not seriously militate
against the theory. The cause is local, and the Samiel and the sand
storm of the desert, is but another phase of the question, explicable on
the same general principles. From the preceding remarks it will be seen,
that in order to foretell the character of particular days, a previous
knowledge of the weather at that particular place, and for some
considerable time, is requisite; and hence the difficulty of laying down
general rules, until the theory is more fully understood.
MODIFYING CAUSES.
We now come to the causes which are auxiliary and interfering. It is
natural that we should regard the sun as the first and most influential
of these causes, as being the source of that variation in the
temperature of the globe, which alternately clothes the colder regions
in snow and verdure. The heat of the sun undoubtedly causes the ether of
the lower atmosphere to ascend, not by diminution of its specific
gravity; for it has no ponderosity; but precisely by increase of
tension, due to increase of motion. This aids the ascensional movement
of the air, and therefore, when a vortex is in conjunction with the sun,
its action is increased--the greatest effect being produced when the
vortex comes to the meridian a little before the sun. This has a
tendency to make the period of action to appear dependent on the phases
of the moon, which being the most palpable of all the moon's variations,
has been naturally regarded by mankind as the true _cause_ of the
changes of the weather. Thus Virgil in his Georgics, speaking of the
moon's influence and its signs:
"Sin ortu in quarto (Namque is certissimus auctor)
Pura, nec obtusis per cœlum cornibus ibit;
Totus et ille dies, et qui nascentur ab illo,
Exactum ad mensem, pluviâ ventisque carebunt."
Hence, also, in the present day we hear sailors speak of the full and
change, or the quartering of the moon, in connection with a gale at sea;
thus showing, at least, their faith in the influence of the phenomenon.
Yet it is actually the case, at certain times, that in about latitude
40° and 41°, the storms appear about a week apart.
There is some reason, also, to suspect, that there is a difference of
temperature on opposite sides of the sun. As the synodical rotation is
nearly identical with the siderent period of the moon, this would
require about forty-four years to run its course, so as to bring the
phenomena to exact coincidence again. Since these observations were
made, it is understood that Sig. Secchi has determined that the
equatorial regions of the sun are hotter than his polar regions. It may
be owing to this fact, that we have inferred a necessity for a change,
whose period is a multiple of the sun's synodical rotation, but it is
worthy of examination by those who possess the necessary conveniences.
Another period which must influence the character of different years,
depends on the conjunction of the perigee of the lunar orbit with the
node. Taking the mean direct motion of the moon's perigee, and the mean
retrograde motion of the node, we find that it takes six years and one
day nearly from conjunction to conjunction. Now, from the principles
laid down, it follows, that when the perigee of the orbit is due north,
and the ascending node in Aries, that the vortices of the earth will
attain their greatest north latitude; and when these conditions are
reversed, the vortices will reach their highest limit in the lowest
latitude. This will materially affect the temperature of the polar
regions. In the following table, we have calculated the times of the
conjunctions of the apogee and pole of the orbit, taking the mean
motions. It may be convenient to refer to by-and-bye, remembering that
when the conjunction takes place due south, the vortices reach the
highest, but when due north, the vortices in the northern hemisphere
have their lowest upper limit:
CONJUNCTION OF APOGEE AND POLE OF ORBIT.[24]
Year. Month and Day. Longitude.
1804, April 18th, 220°
1810, " 17th, 104
1816, " 16th, 348°
1822, " 15th, 232
1828, " 14th, 116
1834, " 12th, 360
1840, " 11th, 244
1846, " 10th, 128
1852, " 9th, 12
1858, " 8th, 255
1864, " 7th, 139
1870, " 6th, 23
1876, " 5th, 267
By this we see that the vortices have never attained their highest limit
during the present century, but that in 1858 their range will be in a
tolerable high latitude, and still higher in 1876--neglecting the
eccentricity of the orbit.
A very potent influence is also due to the heliocentric longitude of the
sun, in determining the character of any given year. Let us explain:
The moon's inertia forces the earth from the mechanical centre of the
terral system, but is never able to force her clear from the central
axis. With the sun it is different. He possesses many satellites
(planets). Jupiter alone, from his great mass and distance, is able to
displace the whole body of the sun. If other planets conspire at the
same side, the centre of the sun may be displaced a million of miles
from the mechanical centre of the solar system. Considering this centre,
therefore, as the centre of an imaginary sun, from which heliocentric
longitudes are reckoned, the longitude of the real sun will vary with
the positions of the great planets of the system. Now, although this
_systematic_ longitude will not be exactly similar to the heliocentric
longitude reckoned from the sun's centre, yet, for the purposes
intended, it will correspond sufficiently, and we shall speak of the
longitude of the sun as if we reckoned heliocentric longitudes from the
mechanical centre of the system. When we come to consider the solar
spots, we shall enter into this more fully. In the following diagram we
shall be able to perceive a cause for variation of seasons in a given
year, as well as for the general character of that year.
[Illustration: Fig. 21]
Let S represent the centre of the sun, and the circle a vertical section
of the sun, cutting; through the centre,--SJ being in the equatorial
plane of the vortex, of which ZZ′ represents the axis. As the ether
descends the poles or axis at Z, it is met by the current down the
opposite pole, and is thence deflected in radii along the equatorial
plane to J. But on the side S, the ether is opposed by the body of the
sun; its direction is consequently changed, and cross currents are
produced, assuming it as a principle, that the ethereal fluid is
permeable by other currents of similar matter, and that it tends always
to move in right lines. This granted, it is evident that, in passing the
sun, the quick moving ether forms a conical shell, (the sun being at the
apex,) so that the strongest current of ether is in this conical shell,
or at the surface of this conical space. As the plane of the ecliptic is
not much inclined to the sun's equator, and this last probably not much
inclined to the plane of the vortex, should the earth have the same
_heliocentric_ longitude at the time, (or nearly the same,) she would
be in an eddy, as respects the radial stream, and be protected from its
full force by the body of the sun.
Now, the ether comes down the axis with the temperature of space, and
may possibly derive a _little_ additional temperature in passing over
the body of the sun; so that in this position the earth is protected
from the chilling influence of the radial stream, by being protected by
the body of the sun. And although, from the immense velocity of the
ether, it cannot derive much additional temperature, there may still be
an appreciable difference, due to this cause.
It is the chilling influence of the ethereal stream which originated the
idea among philosophers, of _frigorific impressions, darted from a clear
sky_. In some years the sun will be nearly in the centre of the system;
in other years the axis of the vortex will not come near the sun. And as
the sun's longitude may vary through the entire circle, it may happen
that the earth's longitude shall coincide in winter or summer, or spring
or autumn. When, however, the earth emerges from the protection of the
sun, and enters the conical shell, considered as a space of considerable
depth, she will again be exposed to the full force of the radial stream,
rendered more active by the previous deflection, and by the numerous
cross currents pervading it; so that a mild and calm winter may be
succeeded by a cold and stormy spring. The present season, (1853) the
earth's longitude coincided with the sun's longitude in about 135°, and
consequently was in the conical space spoken of, during February and
March; but the radius vector of the sun's centre, being then less
than 300,000 miles, the protection was not as complete as it is
sometimes. Still, the general fineness of these months was remarkable;
yet in April and May, when the earth became again exposed to the action
of the solar stream, the effect was to retard the spring, and disappoint
the prognostications of the weather-wise. In applying these principles,
we must consider the effect in those latitudes which are more readily
affected,--that is, in the temperate zone, midway between the two
extreme zones of heat and cold.
In 1837 and 1838, the longitude of the sun's centre corresponded with
the earth's, in August and September, when there was neither rain nor
electrical excitement; and consequently those seasons were sickly over
the whole country. Now, there is another cause which renders the months
of August, September, and October, deficient in electrical energy, and
consequently more prone to be sickly. If, therefore, the two causes
unite their influence, the autumnal months will be more sickly at those
times. This last cause, however, only affects the _northern latitudes_
in autumn, and consequently, _ceteris paribus_, the autumnal months
should not be so proverbially sickly in the southern hemisphere. This
is, however, only suggestive.
Again, in 1843, the winter was very mild in January and February; but in
March it turned cold and stormy, and continued through April. In this
year the longitude of the sun was nearly the same as in 1853,--the two
longitudes of the earth and sun corresponding about the last of January;
but in March, the earth forsook the comparative calm produced by the
sun's position, and hence the greater cold.[25]
Thus it appears at every step we take, that the different members of the
solar system do indeed belong to the same family, whose least motions
have their influence on the rest. Who could have anticipated that the
position of Jupiter in his orbit had anything to do with the health of
this remote planet, or with the mildness of its seasons? In this we have
a clue to the origin of that astrological jargon about planetary aspects
being propitious or malign. Philosophers are even yet too prone to wrap
themselves in their mantle of academic lore, and despise the knowledge
of the ancients, while there is reason to believe that the world once
possessed a true insight into the structure of the solar system. As war
became the occupation of mankind, under the despotic rule of ambition,
so truth retired, and ignorance seizing upon her treasures, has so
mutilated and defaced them, that their original beauty no longer
appears. Let us hope that the dawn of a better day is approaching.
There is yet another cause (just alluded to) which modifies the action
of the vortices.
We have shown that, if the periodic times of the planets are
approximately equal to the periodic times of the contiguous parts of the
solar vortex, the density of the ether is directly as the square roots
of the distances from the centre. As the earth is at her perihelion
about the first of January, the density of the surrounding ether is then
less than in other parts of the orbit; consequently, if we suppose that
there is a continual tendency to equilibrium, the ether of space must
press inwards, during the time between the perihelion and aphelion,
(_i.e._ from January to July,) lowering the temperature and increasing
the electrical action of those months. As the distance from the sun is
most rapidly augmenting about the first of April, and the effective
power of the sun's radiation is most rapidly increasing in May; by
combining the two we shall find, that about the first of May we shall
have considerable electrical action, and cold weather. This explains
also, in part, the prevalent tradition of certain days in May being very
cold.[26] When the earth leaves the aphelion, a reaction takes place,
being most rapid in September. There is then an _escape_ of ether from
the earth, which keeps up the temperature, and causes these months to be
sickly, from the negative electrical state of the atmosphere. In the
southern hemisphere, the effects in the same season will be reversed,
which may partly account for the greater degree of cold in that
hemisphere, and for accelerating the approach of both summer and winter,
while in the north they were both retarded.
We must now advert to another cause, which of all others is probably the
most important, at least to the other members of the solar system.
In every part of the solar vortex the ether is continually pressing
outwards. We are not now speaking of the radial stream, but of the
slower spiral motion of the ether around the axis of the vortex, whose
centrifugal force is bearing the whole body of the ether outwards, thus
rarefying the central parts, and thus giving rise to the polar influx,
from which arises the radial stream. This may be made more intelligible,
by reflecting that the polar current is comparatively dense ether, and
that the length of the axis of the vortex prevents this influx current
coming in sufficient quantities to restore an equilibrium in the density
of the medium. Yet, what does come down the poles, is distributed
rapidly along the equatorial plane, leaving the space still rarefied.
Now we perceive, that in order for the radial stream to continue in
action, requires the whole medium of the vortex to be also moving
outward; it is therefore continually condensed as it proceeds. This
condensation necessarily converts much of the specific heat of the ether
into sensible heat; so that the _temperature_ of the medium is
continually increasing, as the distance from the sun increases.
When we contemplate the solar system as the emanation of one Great Mind,
we naturally seek for evidence of the wisdom of a supreme intelligence
in _all_ the arrangements of that system. But, however humbly and
reverently we may speak of these arrangements, we can scarcely avoid the
wish, that the planetary distances had been differently arranged, if
Newton's doctrine be true, that space is a vacuum, and that the heat of
a planet, is inversely as the squares of the distances from the sun.
For, to speak of the temperature of space, except as dependent on this
law, is one of those many incomprehensible inconsistencies with which
philosophers are chargeable. If the Newtonian philosophy is literally
true, space has _no temperature_, and the surface heat of the planet
Neptune is nearly 1,000 times less than on our own globe. Again, on
Mercury it is seven times greater, which heat would scorch and consume
every organic substance on the earth, and speedily envelope the boiling
ocean in a shroud of impermeable vapor. Granting even that space may not
be a vacuum, and yet the law of gravitation be true, we may still be
allowed to consider both Saturn and Uranus and Neptune, as inhospitable
abodes for intelligent creatures; and, seeing the immensity of room in
the system, there is no reason why these planets might not have been
permitted to revolve nearer the great source of light and life and
cheering emanations. To suggest the resources of Omnipotence is no
argument. He has surrounded us with analogies which are seen, by which
we may attain a knowledge of those which are not seen; and we have every
reason to suppose that the great Author of nature is not indifferent to
the aspects under which his works reveal him unto his creatures. Yet
there is (on the above hypothesis) an apparent want of harmony in the
planetary distances; and if frail mortality may be permitted to speak
out, an explanation is needed to obviate this seeming anomaly in the
economy of the world. The more we learn of the physical arrangements of
the universe, the more do they correspond with our experience of the
nice adaptation of the means to the end which obtains in our own globe,
and we can only judge of other planets by the analogies around us. Here,
there, are extremes of temperature it is true: it is necessary there
should be, and we can see and understand the necessity in all such
cases, and how they conduce to the general average of good. But,
astronomers can give no reason why it is necessary that some planets of
our system should be placed so remote that the sun is frittered down to
a star, whose heatless light is but a mockery to those frigid realms.
Now, according to this theory, the temperature of Neptune may be far
more uniform and conducive to life than that of our own globe. The
chilling influence of the solar stream at that planet being nearly null,
and the temperature of the surrounding space far greater. So also
Mercury, instead of being the burning planet of the schools, may suffer
the most from cold.
The planet Mars is generally considered, of all the members of the
system, most nearly to resemble our own world. The telescope not only
reveals seas and continents, but the snowy circles round his poles,
which appear to increase and diminish, as his winter is beginning or
ending. This planet's ecliptic is similar to our own in inclination or
obliquity, his distance, also, is far greater, and his winter longer;
yet, for all this, his snow zones are less than on our own globe. This
anomalous fact has, we believe, never been noticed before; but it is
explicable on the theory, and therefore confirms it. Mars has no
satellite, and therefore his centre will be coincident with the centre
of the marsial vortex. There will be no _lateral vortices_ to derange
his atmosphere, and if the axis of his vortex coincides also with the
axis of the planet, the central vortex will be continually over the
poles, _and there will be no storms on the planet Mars_. A capital fact
connected with this, is the want of belts, as in Jupiter and Saturn; for
these planets have satellites, and if _they_ are not massive enough, the
belts may be produced by an obliquity in the axis of the Jovial and
Saturnial vortices. If Mars had an aurora like the earth, it is fair to
presume the telescope would ere this have shown it. He is, therefore, in
equilibrium. In applying this reasoning to the earth, we perceive that a
certain influence is due to the difference of temperature of the
ethereal medium surrounding the earth, at perihelion and aphelion, being
least at the former, and greatest at the latter.
As a modifying and interfering cause in the action of the vortices, we
must mention the great natural currents of the atmosphere, due to the
earth's rotation.
It is considered that the sun is the principal cause of these great
currents. By elevating the surface atmosphere of the equator, a lateral
current is induced from the north and south; but on account of the
enlarging circles of latitude, their direction tends more from the
north-east and south-east. These currents are usually called the trades.
Without disputing the correctness of this, it may be doubted whether the
whole effect is due to the sun. As this principle affects the ocean
likewise, it is necessary to look into it; and in order to simplify the
question, we will first suppose our globe covered entirely by the ocean,
without any protuberant land.
Let us assign a uniform depth of ten miles to this ocean. In the Fig.
following, the two circles will represent the surface and bottom of the
ocean respectively. The axis of rotation is thus represented by the line
PP′. Let us consider two particles of water at m and n, as feeling the
influence of this rotation; they will, of course, be both urged towards
the equator by the axifugal force. Now, every particle in the ocean
being also urged by the same force, it might be supposed that after a
protuberant mass of water had accumulated at the equator EE′, the whole
ocean would be in equilibrium. This would not follow. The particle at m
is urged by a greater force than n; consequently the particle at n is
overborne by the pressure at m. Considering both in the same direction,
yet the particle at n must give way, and move in the opposite direction.
Just as the heaviest scale of the balance bears up the lightest,
although both gravitate towards the same point. This is so self-evident
that it would seem unnecessary to dwell upon it, had not the scientific
world decided that the rotation of the earth can cause no currents
either in the atmosphere or in the ocean.
[Illustration: Fig. 22]
The axifugal forces of the two particles m and n are directly as the
lines Mm and Nn, and if the gravitating forces were also as the radii Tm
and Tn, no motion would be produced. Admitting even the Newtonian law to
be rigidly exact, the earth cannot be considered a homogeneous globe,
but, on the contrary, the density of the central parts must be nearly
thirty times greater than the density of the surface of the ocean. The
ratio of the gravitating forces of these two particles is, therefore,
less than the ratio of their respective radii, and the axifugal tendency
of the particle at n is more than proportionally restrained by the
central gravitation; and hence m will move towards the equator, and n
towards the poles, as represented in the Fig.
It is on account of the overwhelming momentum of the surface waters of
the South Pacific over the North, that the Pacific, at Panama, stands
six or seven feet higher than the Atlantic. We shall again allude to
this interesting fact.
According to newspaper reports of a lecture, delivered in New York, by
Lieut. Maury, U. S. N., this gentleman endeavors to explain the currents
of the ocean, by referring them to evaporation in the tropics. The vapor
leaves the salt of the water behind, and thus, by continual
accumulation, the specific gravity of the tropical waters is greater
than that of the superficial waters nearer the poles; the lighter
water, therefore, passes towards the equator, and the heavier water
below, towards the poles. If this be a correct statement of that
gentleman's theory, fidelity to our standards compels us to question the
soundness of the conclusion. The mere fact of the surface water of the
ocean being lighter than that of the bottom, cannot on any known
principles of science cause any movement of the surface waters towards
the equator. When such an acute and practical physicist is driven, by
the palpability of the fact that the polar waters are continually
tending towards the equator, to seek the cause in the tropical
evaporation, it shows that the dogma, which teaches that rotation can
produce no motion, is unsound.
Sir John Herschel, in speaking of the solar spots, says: "We may also
observe that the tranquillity of the sun's polar, as compared with his
equatorial regions (if his spots be really atmospheric), cannot be
accounted for by its rotation on its axis only, but must arise from some
cause external to the sun, as we see the belts of Jupiter and Saturn and
our trade winds arise from a cause external to these planets combining
itself with their rotations, which _alone_ (and he lays an emphasis on
the word) can produce no motions when once the form of equilibrium is
attained."
With respect to the origin of the solar spots, we have no disposition to
question the conclusion; but, as regards the _principle_ laid down, that
rotation can produce no motions when once the form of equilibrium is
attained, we must unequivocally dispute it. If our atmosphere were of
uniform density, the rotation of the earth would cause no current such
as we have described; with our atmosphere as it is, the result will be
different. The momenta of two portions of matter are the products of
their inertiæ by their motions, and, in the present case, we must take
the inertiæ of equal spaces. A cubic inch of air at the surface, and at
three miles above the surface, is as 2 to 1; but their centrifugal
velocity varies only as the radii of the respective spheres, or as 1320
to 1321. In the polar regions, therefore, the momentum of the surface
air preponderates, and, in this case, the _surface_ current is towards
the equator, and the upper current towards the poles. When, however, the
centrifugal velocity is considerably increased in a lower latitude, and
the curvature of the surface becomes more and more inclined to the
direction of that resolved part of the centrifugal force, which is
always _from_ the axis, the surface layers will evince a tendency to
leave the surface, and an intermingling will then take place in the
space between latitude 70° and 50°, or in latitude 60°. As this layer is
continually urged on in the same direction by the surface layer of
latitudes above 60°, the upper layer now becomes a current setting
_towards_ the equator, and, consequently, the back current occupies the
surface. Now, considering that the rarefying action of the sun is
elevating the air under the equator, there must necessarily be an upper
current from the equator to the poles; so that if we conceive the two
currents to meet about latitude 30°, there will be a second
intermingling, and the current from the poles will again occupy the
surface. Thus, we regard a part of the effect of the trades to the
rotation of the earth, which is the chief impelling power at the poles,
as the sun is at the equator; and the latitudes 60° and 30° will be
marked by some especial phenomena of temperature, and other
meteorological features which do actually obtain. These would be much
more marked if the irregular configuration of land and sea, the
existence of mountain chains, and the different heating power of
different latitudes, owing to the unequal distribution of the land, did
not interfere; and the currents of the air (disregarding the deflection
east and west) might then be represented by a treble link or loop, whose
nodes would vary but little from latitudes 30° and 60°. As it is, it
has, no doubt, its influence, although unimportant, when compared with
the disturbing action of the ethereal vortices.
There is another phenomenon due to the action of the radial stream,
which has given much trouble to the physicist, and which has yet never
been explained. This is the horary oscillations of the atmospheric
pressure which, in some countries are so regular that the time of day
may be ascertained by the height of the barometer. According to
Humboldt, the regularity of the ebb and flow in the torrid regions of
America, is undisturbed by storms or earthquake. It is supposed that the
maxima occur at 9 A.M. and 10½ P.M., and the minima at 4 A.M. and
4¼ P.M. From the morning minimum to the morning maximum is,
therefore, five hours; from the evening minimum to the evening maximum
is 6¼ hours; from the evening maximum to the morning minimum is 5½
hours, and from the morning maximum to the evening minimum is 7¼
hours. Again, these oscillations are greatest at the equator, and
diminish with the increase of latitude.
[Illustration: Fig. 23]
If we suppose the earth's axis perpendicular to the plane of the vortex,
and P the pole in the above figure, and SP the line joining the centre
of the earth and sun, M and m will represent the points in the earth's
equator where it is midday and midnight respectively. The solar stream
penetrates the terral vortex; and strikes the earth's atmosphere along
the lines parallel to SP. The direct effect would be to pile up the
atmosphere at N and n; and therefore, were the earth at rest, the
maximum would be at 6 A.M. and 6 P.M., and the minimum at midday and
midnight; but the earth rotating from N towards M, carries along the
accumulated atmosphere, being more sluggish in its motions than the
producing cause, which cause is still exercised to force it back to N.
From this cause the maximum is now found at K. For a like reason the
minimum at M would be found at L, but on account of the motion of the
earth being now in the same direction as the solar stream, the minimum
is found still more in advance at k; so that, according to the theory,
the interval between the morning maximum and the evening maximum, should
be greater than the interval between the evening maximum and the morning
maximum; and so it is, the first being 13½ hours and the last 10½
hours. The morning minimum should also be less marked than the evening
minimum, and this also is a fact. The effect also should be greater in
the tropics than in high latitudes, which again also obtains; being 1.32
French lines at the equator, and only 0.18 at latitude 70°. Had the
earth no obliquity, the effect would be as the squares of the cosines of
the latitude; but the ratio is diminished by the inclination of the
axis. But there are other variations of the barometer of longer period,
apparently depending on the phases of the moon, but which cannot be
reconciled to the attracting power of the moon as an atmospheric tide;
and Arago concluded that they were due to some _special cause_, of which
the nature and mode of action are unknown. Perhaps this theory will
obviate the difficulty, as although the central vortex comes to the
meridian at the same time as the moon, its effect will be different on
the inferior meridian to what it is on the superior one; whereas the
moon's attraction should be the same on both. That the passage of a
vortex over or near a particular place should affect the barometer, is
too obvious to need explanation, and therefore we may say that the
theory will explain all those varieties both small and great, which have
caused so much speculation for the last fifty years.
TERRESTRIAL MAGNETISM.
In applying the theory to the magnetism of the earth, we must bear in
mind that the earth is probably magnetic by induction, and not in virtue
of its own specific action. The rotation of the surrounding ether, and
the consequent production of a radial stream, calls the ether into
motion within the earth's interior, as well as on the surface; but it
does not follow that the ether shall also enter the earth at its poles
and escape at its equator, for the obliquity of the vortex would
interfere with this result. It is sufficient that this does occur in the
terral vortex immediately surrounding the earth. From late experiments
it is pretty well established that the axial direction of the needle,
(and of other bodies also,) is due to peculiar internal arrangement in
laminæ or layers, the existence of which is favorable to the passage of
the magnetic current.
According to the experiments[27] of Dr. Tyndal, it is found that the
magnetism of a body is strongest along the line of greatest density. As,
therefore, the laminæ of bodies may be considered planes of pressure,
when these planes are suspended horizontally, the directive force is
greatest, and the longest diameter of the body sets axial. On the other
hand, when the body was suspended so that the laminæ were vertical, the
longest diameter set equatorial. Now, we know that the crust of the
earth is composed of laminæ, just as the piece of shale in Doctor
Tyndal's experiments, and that these layers are disposed horizontally.
And whatever force originally arranged the land and water on our globe,
it is evident that the continents are longest from north to south, and
therefore correspond to the natural direction of the magnetic force.
In consequence of the intrinsic difficulties of this question, and the
mystery yet attaching to it, we may be permitted to enter a little more
minutely into it, and jointly consider other questions of interest, that
will enable us to refer the principal phenomena of terrestrial magnetism
to our theory.
We have before adverted to the discrepancies in the earth's compression,
as determined by the pendulum, and also to the uncertainty of the moon's
mass, as deduced from the nutation of the earth's axis. It is also
suspected that the southern hemisphere is more compressed than the
northern; and other phenomena also point out the inadequacy of the law
of gravitation, to account for the figure of the earth.
From the invariability of the axis of rotation, we must conclude that
whatever form is the true form, it is one of equilibrium. In casting our
eyes over the map of the world, we perceive that the surface is very
unequally divided into land and sea; and that the land is very unequally
arranged, both north and south, and east and west. If we compare the
northern and southern hemisphere, we find the land to the water about 3
to 1. If we take the Pacific portion, and consider the north end of New
Zealand as a centre, we can describe a great circle taking in one half
the globe, which shall not include one-tenth of the whole land. Yet the
average height of the remaining nine-tenths, above the level of the sea,
is nearly 1,000 feet. Call this nine-tenths nearly equal to one-fourth
of the whole surface, and the protuberant land in the hemisphere,
opposite the South Pacific, amounts to 1/30,000 part of the whole mass
of the earth, or about 1/700 of the mass of the moon. Again, the mean
density of the earth is about 5½--water being unity,--and the mean
density of the surface land is only about half this: but three-fourths
of the whole surface is water. Hence, we see that the materials of the
interior of the earth must be either metallic or very compressible. To
assign a metallic nucleus to the earth, is repugnant to analogy; and it
is not rendered even probable by facts, as we find volcanic emissions to
contain no heavier elements than the sedimentary layers. Besides, there
are indications of a gradual increase of density downwards, such as
would arise from the compressibility of the layers. Seeing, therefore,
the equilibrium of the whole mass, and the consequent hydrostatic
balance of the land in the sea,--seeing also the small compressibility
of the solid portions, and the great compressibility of the fluid, the
inference is legitimate that the whole is hydrostatically balanced, and
that our globe is a globe of water, with an intermediate shell of land,
specifically lighter than the fluid in which it is suspended. Where this
shell is of great thickness, it penetrates to greater depths, and
attains to greater elevations above the surface of the aqueous globe;
where it is less thick, it is found below the surface, and forms the
bottom of the upper ocean. Recent soundings give much greater depths to
some parts of the ocean, than the most elevated land upon the globe.
Captain Denham, of H. B. M. ship Herald, lately sounded in 37° south and
37° west, and found bottom at 7,706 fathoms, or about nine English
miles.
As the interior portions of our globe are totally unknown, and the
compressibility of water is well established, it is just as sane to
consider water the most abundant element of nature, as solid land. The
great question to ask is, whether there may not be other phenomena
incompatible with this supposition? It is plain that the permanency of
terrestrial latitudes and longitudes would be unaffected by the
conditions we have supposed. Would the precession of the equinoxes be
also unaffected? Mr. Hopkins has entered into such an investigation, and
concludes: "Upon the whole, then, we may venture to assert that the
minimum thickness of the crust of the globe, which can be deemed
consistent with the observed amount of precession, cannot be less than
one-fourth or one-fifth of the radius of the earth." These
investigations were made on the hypothesis of the interior fluidity
being caused by the fusion of the central portions of a solid globe; but
it is evident that the analytical result would be the same if these
central parts were water, inclosed by an irregularly-spherical shell of
land. Nor would the result be affected, if we considered certain
portions of the interior of this solid shell to be in a state of fusion,
as no doubt is the case.
May not the uncertainty of the mass of the moon, be owing to the fact
that this shell is not so rigidly compacted but that it may yield a
little to external force, and thus also account for the tides in the
Pacific groups, rather obeying the centrifugal force due to the orbit
velocity of the earth, than the attraction of the moon?
Since the days of Hipparchus the sidereal day has not diminished by the
hundredth part of a second; and, consequently, seeing that the
contraction of the mass must be limited by the time of rotation, it is
inferred that the earth has not lost 1/508th of one degree of heat since
that time. This conclusion, sound as it is, is scarcely credible, when
we reflect on the constant radiation into a space 60° below zero. Admit
that the globe is a globe of water, whose average temperature is the
temperature it receives from the sun, and the difficulty vanishes at
once. Its diameter will be invariable, and the only effect of the
cooling of the solid parts will be to immerse them deeper in the water,
to change the _relative_ level of the sea without changing its volume.
This is no puerile argument when rightly considered; but there is
another phenomenon which, if fairly weighed, will also conduct us to the
same views.
It is now a fact uncontroverted, that the sea does actually change its
level, or rather, that the elevation of continents is not only apparent
but real. The whole coast of Sweden and Finland is rising at the present
day at the rate of four feet in a century, while on the south a contrary
effect is produced. Various hypotheses have been formed concerning this
interesting fact. Yet from the indications of geology, it must have been
an universal phenomenon in the early ages of the world, in order to
account for the emersion of sedimentary deposits from the fluid which
deposited them. May not internal fires be yet spreading, and the
continents expanding instead of contracting? And may there not be an
inequality in this process, so as necessarily to immerse in one
direction nearly as much as to elevate in another? One fact is certain,
the elements are scattering the materials of the land along its Oceanic
coasts, which of itself must produce a very minute effect in disturbing
the hydrostatic balance; but a more efficient agent is the earthquake
and volcano.
The upheaving of tracts of land by earthquakes, as on the coast of Chili
would thus be satisfactorily explained, by attributing a certain
resistance due to cohesion or friction preventing a _gradual_ change of
level, but producing it suddenly by the jar of the earthquakes. May we
not inquire also, whether the facility with which the earth seems moved
by this destructive agent, does not point to the same solution as the
irregularity of the figure of the earth?
This is a subject on which it is allowable to speculate, especially if
any light can be thereby thrown on the still more mysterious source of
terrestrial magnetism. It is for such a purpose that we have permitted
ourselves to digress from that subject. In this connection we also may
acknowledge our indebtedness to the sacred volume for the first germ of
this theory of the weather.
Believing in the authenticity of the Mosaic history of the deluge, the
author found it difficult to refer that event to other than natural
causes, called into action by the operation of other causes, and all
simultaneous with the going forth of the fiat of Omnipotence. Thus
reasoning, he was led to regard the deluge as a physical phenomenon
inviting solution, and as a promising exponent to the climatology of
the early world. He looked upon the bow of promise, as the autograph of
the Creator, the signature to a solemn bond, upon which the eye of man
had never before rested. But if there was no rainbow before the deluge,
there was no rain; and following up this clue, he was not only enabled
to solve the problem, but also led to the true cause, which produces the
principal commotions in our atmosphere.
Science boasts of being the handmaid of religion; yet there are names of
note in her ranks who have labored rather to invest this phenomenon with
the mantle of fable, and to force it into collision with the records
graven on the rocky pages of geognosy. But the world is ever prone to be
captivated by the brilliancy of misapplied talents, instead of weighing
merit by its zeal in reconciling the teachings of those things which are
seen, with those which are revealed.
If our globe be constituted as we suppose, the land might experience
repeated submersions, without involving the necessity of any great
departure from established laws. And we might refer to the historical
record of one of these, with all the minute particulars as positive
data, imposing on us the necessity of admitting that the solid parts of
the globe are hydrostatically balanced in the sea. But, modern science
is not always correctly defined when called the pursuit of truth, nor
human learning the means of discovering it.
If we could divest ourselves of this prejudice, we should have a ready
solution of the difficulty presented by the earth having two north
magnetic poles, and probably two also in the south. For, by regarding
the old and new continents as two distinct masses of land whose bases
are separated by 6,000 miles of water, we recognize two great magnets,
dependent, however, for their magnetism, on the rotation of the terral
vortex.
This is no place to enter into a lengthy discussion of such a difficult
subject as magnetism, but we may be allowed to enter a protest against
the current theory of electro-magnetism, viz.: that a force is generated
by a galvanic current at right angles to the producing cause, which is
contrary to the fundamental principles of mechanics. We may conceive
that a current is induced from or to the surrounding space by the
rarefaction or condensation attending the transmission of such a current
along a wire, and that rotation should follow, just as a bent pipe full
of small holes at the lower end, and immersed in water as a syphon, will
generate a vorticose motion in the water; but mere juxtaposition,
without participation and communication with the general current, is
irrational, and, therefore, not true.
We have always regarded a magnetic needle as a part of the great natural
magnet, the earth; that its north pole actually points to the north, and
its south pole to the south; and, being free to move, it is affected by
the circular motion of the surrounding ether, and by every motion by
which the ether is directed. If there was any attraction between the
earth and the needle, opposite poles would be presented, but it is not
so--the force is merely directive.
MAGNETIC VARIATIONS.
Let us now see whether we cannot assign an adequate cause for the
secular and periodic variations in the inclination and declination of
the needle. These have been generally referred to changes of
temperature, as in fact, also, the magnetism of the earth is sometimes
ascribed to galvanic or electric currents, called forth by a daily
change of temperature. Our theory gives a totally different explanation
of these variations.
In the northern hemisphere, the north point of the needle moves from
east to west in the morning from about 8½ A.M. to 1½ P.M., and
returns to its mean position about 10 P.M. It then passes over to the
east, and again returns to its mean position about 8 or 9 A.M. The
analogy of this motion, with the horary changes in the barometer,
indicate a common origin. Humboldt, in the instructions he drew up for
the Antarctic Expedition under Sir James Ross, says: "The phenomena
of periodical variations depend manifestly on the action of _solar
heat_, operating probably through the medium of thermo electric currents
induced on the earth's surface. Beyond this rude guess, however,
_nothing is yet known of their physical cause_. It is even still a
matter of speculation whether the solar influence be a principal or only
a subordinate cause." That the sun may exert a modifying influence on
the phenomenon is not unlikely, but that he cannot be the principal
cause, is evident from the following considerations. These horary
variations of the magnetic needle are as great at the bottom of deep
mines far removed from solar influence, as on the surface. They are as
great, _ceteris paribus_ on a small island in the midst of the ocean, as
in the interior of continents, where the heating power of the surface is
vastly greater. They are extremely regular, so that between the tropics,
according to the sagacious Humboldt, "the time of the day may be known
by the direction of the needle, as well as by the height of the
barometer."
But what is the cause of these variations? This question is the most
difficult of all physical problems, and we shall only aim at indicating
the causes which are yet perhaps too intricately involved to afford a
positive numerical determination. Admitting the existence of two
principal solid masses whose general direction is from south to north,
and that these masses are more susceptible of permeation by the ethereal
fluid than the waters in which they are suspended, we have a general
solution of the position of the magnetic poles, and of the isogonic,
isoclinic, and isodynamic lines. Considering, too, that the southern
poles of these masses are the points of ingress, and the northern poles
the points of egress, it is easily understood that the ethereal medium
having the temperature of space, will cause the southern hemisphere to
be colder than the northern, and also that the magnetic poles will be
the poles of maximum cold, and the centres respected by the isothermal
and isogeothermal lines.
The general direction of the magnetism of the earth may be considered as
the controlling influence, therefore, in determining the position of the
magnetic needle; but there are other causes which, to some extent, will
modify the result. That half of the globe turned away from the sun will
partake of the density of the ether at that distance, which is greater
than on the side next the sun; the magnetic intensity ought, therefore,
to be greater in the night than in the day. The poles of the great
terrestrial magnets, or even the position of a magnetic needle on the
surface, are continually placed by the earth's rotation in a different
relation to the axes of the terral vortex, and the tangential current,
which is continually circulating around the globe, has its inclination
to a given meridian in a perpetual state of change. If we conceive that
there is a tendency to force the needle at right angles to this current,
we shall have an influence which varies during the day, during the year,
and during the time occupied by a complete revolution of the node. The
principal effect, however, of the horary variation of the needle is due
to the radial stream of the sun, which not only penetrates the
atmosphere, but also the solid crust of the earth. Its principal
influence is, however, an indirect influence, as we shall endeavor to
explain.
No fact in the science of electro-magnetism is, perhaps, better
established than the disposition of an ethereal current to place itself
at right angles to the magnetic meridian, and conversely, when the
current is not free to move, to place the needle at right angles to the
current. Now, the terrestrial magnet or magnets, may be considered to be
surrounded by a body of ether in rotation, which, in the earth, on its
surface, and for some distance from the surface, is made to conform to
the general rule, that is, to circulate at right angles to the magnetic
meridian. Outside this again, the ether more and more conforms to the
position of the axis of the vortex, and this position varying, it must
exert _some_ influence on the surface currents, and, therefore, change
in some degree the position of the magnetic meridian. The radial stream
comes from the sun in parallel lines, and strikes the globe and its
superficial ethereal envelope just as we have shown its action on the
atmosphere; but in this last case the magnetic equator is not a great
circle, neither can we suppose its effects to be an accumulation of a
fluid which is imponderable at points 90° from the plane passing through
the centre of the earth and sun, and coincident with the plane of the
central meridian, and a depressing effect on that meridian. Its precise
influence must be, from the nature of the cause, to deflect the circular
current towards the poles, in places less than 90° from the meridian,
and a contrary effect must be produced in places greater than 90° from
the meridian. Let us assume, for argument's sake, that the magnetic
poles of the earth correspond to the poles of rotation, the parallels of
latitude will, therefore, represent the ethereal currents circulating
around the globe. Now, at sunrise, the radial stream of the solar vortex
is tangential to the surface, and, therefore, can produce no change in
these currents. As the sun ascends say about 8 or 9 A.M., the radial
stream striking only the surface of the earth perpendicularly in that
place where the sun is vertical (which we will suppose at the equator),
streams off on every side, as the meridians do from the pole, and the
circles of latitude (that is the ethereal currents) being parallel to
the equator, they are met by the radial stream obliquely, and deflected
towards either pole. By this deflection they are no longer at right
angles to the meridians. But, from the principle of reaction above
noticed, the magnetic meridians will place themselves at right angles to
the current, or, in other words, the magnetic pole will change its
position on the surface of the earth with respect to that particular
place. But, in other parts of the world, the meridians are in opposite
phases at the same instant of absolute time; therefore, the magnetic
poles are not points, but wide areas enclosing the magnetic poles of all
the countries under the sun. As this conforms to observation, it is
worthy our especial attention, and may be understood by the subjoined
figure, in which the oblique curves represent the course of the
tangential current in the different positions of the sun, the parallel
lines representing the solar radial stream.
[Illustration: Fig. 24]
As the sun gains altitude the action of the radial stream is at a
greater and greater angle to the circular currents, and attains its
maximum at noon, still acting, however, after noon; but seeing that the
circular current possesses a force of re-action, that is, that the
magnetism of the earth is ever striving to bring these currents to their
natural direction, an hour or two after noon, the currents tend again to
the equator, and the maximum deflection is passed, and finally ceases a
few hours after sunset. Now let us attend to what is going on on the
opposite side of the world. The radial stream passing over the polar
regions, now produces a contrary effect; the ethereal atmosphere of the
great magnet is accumulated on the farthest side from the sun, by the
action of the radial stream passing over the polar region, the parallel
currents are now bent towards the equator, being at a maximum in places
where it is an hour or two past midnight. Before they were concave to
the equator, and now they are convex; the magnetic meridian is therefore
deflected the contrary way to what it was in the day time, by the same
principle of reaction. After the maximum, say at 4 A.M., the deflection
gradually ceases, and the magnetic meridian returns to its mean position
at 8 or 9 A.M. These times, however, of maximum and minimum, must vary
with the time of the year, or with the declination of the sun, with the
position of the moon in her orbit, with the perigee of the orbit, and
with the place of the ascending node; there are also minor influences
which have an effect, which present instrumental means cannot render
appreciable.
What says observation? The needle declines from its mean position in the
whole northern hemisphere to the westward, from about 8.30 A.M., until
1.30 P.M.; it then gradually returns to its mean position by 10 A.M.
After 10 P.M., it passes over to the eastward, and attains its maximum
deflection about three or four hours after midnight, and is found again
at its mean position about 9 A.M. Now, this is precisely the direction
of the deviation of the magnetic meridian, the needle therefore only
follows the meridian, or still continues to point to the temporary
magnetic pole. And although we have assumed, for the sake of simplicity,
that the mean magnetic pole corresponds to the pole of rotation; in
truth there are two magnetic poles, neither of which correspond; yet
still the general effect will be the same, although the numerical
verification will be rendered more difficult.
In the southern hemisphere the effect is the reverse, (this southern
hemisphere, however, must be considered separated from the northern by
the magnetic equator, and not by the geographical one,) the needle
declines to the eastward in the morning, and goes through the same
changes, substituting east for west, and west for east. Does observation
decide this to be to be a fact also? Most decidedly it does; and this
alone may be considered a positive demonstration, that the theory which
explains it is true. The contrary deflection of the needle in the
northern and southern hemisphere may be formally proclaimed as utterly
beyond the reach of the common theory of magnetism to explain. This
difficulty arises from considering the needle as the disturbed body
instead of the earth; and also from the fact that the effect of solar
heat must be common to needles in both hemispheres, and act upon similar
poles, and consequently the deflection must be in the same direction.
But a still more capital feature is presented by the discovery of
Colonel Sabine, that the deflection is in contrary directions at the
Cape of Good Hope, at the epoch of the two equinoxes. This arises from
the great angle made by the magnetic meridian at this place, with the
terrestrial meridian--the variation being by Barlow's tables, 30° to the
westward. The sun varies in declination 47° throughout the year. At the
southern solstice, therefore the radial stream strikes the circular
current on the southern side, and deflects it towards the equator,
rendering the declination to the westward in the morning; but at the
northern solstice the radial stream strikes the current on its northern
side, and the deflection is eastward in the morning. And the vicinity of
the Cape of Good Hope is, perhaps, the only part of the world where this
anomaly will obtain; as it is necessary not only that the declination
shall be considerable, but also that the latitude shall not be very
great.
Observation also determines that the amount of the horary variation
increases with the latitude. Near the equator, according to Humboldt, it
scarcely amounts to three or four minutes, whilst it is from thirteen to
fourteen minutes in the middle of Europe. The theory explains this also;
for as the circles recede from the equator, the angles made by their
planes with the direction of the radial stream increases, and hence the
force of deflection is greater, and the effect is proportioned to the
cause. We have also a satisfactory explanation of the fact that there
has not yet been discovered a line of _no variation of horary
declination_ as we might reasonably anticipate from the fact that the
declinations are in _contrary directions_ in the northern and southern
hemisphere. This is owing to the ever-varying declination of the sun.
There would be such a line, no doubt, if the axis of the earth were
perpendicular to the plane of the orbit, and the magnetic pole coincided
with the pole of rotation: for then the equator would be such a line.
MAGNETIC STORMS.
But there are also irregular fluctuations in the direction of the
magnetic needle. These depend on the moon, and are caused by the passage
of the vortices over or near to the place of observation. The action of
these vortices is proved to be of variable force, whether arising from
atmospheric conditions, or due to an increased activity of the ethereal
medium throughout the whole system, is at present immaterial. They do
vary, and sometimes the passage of a vortex will deflect the needle a
whole degree. At other times, there are magnetic storms extending over a
great part of the earth's surface; but there is reason to suppose, that
the extent of these storms has been over estimated. Thus, on the 25th of
September, 1841, a magnetic storm was observed in Toronto, and at the
same time there was one felt at the Cape of Good Hope. There is no great
mystery in this. If we suppose the axis of the central vortex, for
instance, to have passed Toronto in latitude 43° 33′ north, in ordinary
positions of the moon, in her orbit, the southern portion of the axis
would be in 33° or 34° south latitude, and consequently would have
passed near the Cape of Good Hope on the same night. Now, we certainly
could not expect the northern portion of the vortex to be intensely
active, without the southern portion being in the same state of
activity. That this is the true explanation is proved by magnetic storms
in the same hemisphere being comparatively limited in extent; as,
according to Gauss and Weber, magnetic storms which were simultaneously
felt from Sicily to Upsala, did not extend from Upsala to Alten. Still
it would not be wonderful if they were felt over a vast area of
thousands of miles as a consequence of _great_ disturbance in the
elasticity of the ether in the terral vortex; as the solid earth must be
permeable to all its motions, and thus be explicable on the general
principles we have advanced.
But besides these variations which we have mentioned, there are changes
steadily going on, by which the isodynamic, isogonic and isoclinic lines
are permanently displaced on the surface of our planet. These must be
attributed to changes of temperature in the interior of the globe, and
to the direction in the progress of subterranean fires, which it may
also be expected will change the isogeothermal lines. But there are
changes, which although of long period, are yet periodic, one of which
is obviously due to the revolution of the lunar nodes in eighteen and a
half years, and the revolution of the apogee in nine years. The first is
continually changing the obliquity of the axis of the vortex, and they
both tend to limit the vortices in their extreme latitudes; but the
planet Jupiter has an indirect influence, which is probably equal, if
not greater, than the action of the moon, in changing the magnetic
declination.
From the investigations of Lamont, it would appear, that the period of
the variations of magnetic declination is about 10⅓ years, while,
more recently, R. Wolfe has suggested the connection between this
variation and the solar spots, and assigns a period of 11.11 years, and
remarks, that it "corresponds more exactly with the variations in
magnetic declination than the period of 10⅓ years established by
Lamont. The magnetic variations accompany the solar spots, not only in
their regular changes, but even in their minor irregularities: this
latter fact is itself sufficient to prove definitely the important
relations between them."[28]
As the planet Jupiter exerts the greatest influence on the sun, in
forcing the centre from the mechanical centre of the system, the
longitude of the sun will in a great measure depend on the position of
this planet; and, in consequence, the sun will generally revolve around
this centre in a period nearly equal to the period of Jupiter. The
sidereal period of Jupiter is about twelve years, but the action of the
other planets tend to shorten this period (at least, that has been the
effect for the last twenty or thirty years), and bring it nearly to the
period assigned by M. Wolfe to the variations in the magnetic
declinations. As this has its influence on the radial stream, and the
radial stream on the declination, we see at once the connection between
them. When we come to a consideration of the solar spots, we shall
exhibit this influence more fully.
AURORA BOREALIS.
Let us now examine another phenomenon. The Aurora Borealis has been
generally considered to be in some way connected with the magnetism of
the earth, and with the position of the magnetic pole. It is certain
that the appearance of this meteor does affect the needle in a way not
to be mistaken, and (although not invariably) the vertex of the luminous
arch will usually conform to the magnetic meridian. Yet (and this is
worthy of attention), the observations made in the North Polar
Expeditions[29] "appear to prove, that in the immediate vicinity of the
magnetic pole the development of light is not in the least degree more
intense or frequent than at some distance from it." In fact, as the
American magnetic pole is, as stated, in latitude 73°, the central
vortex will seldom reach so high, and, consequently, the aurora ought
at such times to be more frequent in a lower latitude. In a late work by
M. de la Rive, this gentleman expresses the opinion, that the cause of
the aurora is not due to a radiation of polar magnetism, but to a purely
electrical action.[30] His explanation, however, is not so satisfactory
as his opinion. Now, we have examined numerous cases of auroral
displays, and never yet found one which could not be legitimately
referred to the action of ethereal vortices. Generally, the aurora will
not be visible, when the upper surface of the atmosphere of that
latitude in which the vortex is known to be (reckoning in the direction
of the magnetic meridian) is below the horizon, which shows that the
brightest portion is in the atmosphere. In latitude 41° even, it may
show itself when the vortex is three days north, more frequently when
one or two days north; but when the vortex passes centrally, or south,
it rarely is seen, and this is the only difficulty in explaining it by
the theory. But, when we reflect that the ether shoots out in straight
lines, and at an angle corresponding to the magnetic dip, we are at no
loss to perceive the reason of this. If each minute line composing the
light were seen endwise, it would be invisible; if there were millions
such in the same position, they could add nothing to the general effect;
but, when viewed sideways, the case would be different, there would be a
continued reduplication of ray upon ray, until in the range of some
hundreds of miles an effect might be produced amounting to any degree of
intensity on record. Now, this is the case when the aurora is
immediately overhead, it will be invisible to those below, but may be
seen by persons a hundred miles south; so, also, when it is to the
south, it is too oblique to the line of vision to be seen, especially as
all the rays to the northward of the observer can contribute nothing to
increase the effect. That it is of the nature of rays very much
diffused, can hardly be doubted; and, therefore, if only of a few miles
in depth, its impressions are too faint to be sensible. By referring to
the record of the weather in the second section of this work, an auroral
display will be found on July 12th, the central vortex having passed a
little to the northward the same evening, and the next day passing south
_descending_. On that occasion the author saw an inclined column, in
profile, due east, and between himself and a line of bluffs and timber,
about eight miles distant; And, he has not any doubt that the mass of
rays began where he stood. As in a shower, every drop, passing through a
conical surface, whose axis passes through the sun and through the eye,
contributes to form the apparently distant rainbow.
The altitude of this meteor has been much exaggerated, especially of
those rings or luminous arches, which are often detached completely from
the luminous bank. On the 24th of May, a bright aurora was visible at
Ottawa, but the author's attention was engrossed by the most brilliant
arch of light he had ever seen. It was all the time south of the zenith,
and had no visible connection with the aurora north. At 9 hours, 59
minutes, 30 seconds mean solar time, Arcturus was in the exact centre of
the band, at which time it was very bright, and full 7° wide. At the
same time, Prof. G.W. Wheeler observed the aurora in Perryville, in the
State of Missouri, only 1° of longitude to the westward, but did not see
the arch.[31] The difference of latitude between the two places being 3°
30′, and the weather, as he states, clear and still, there is only one
reason why he did not see the arch: it must have been too _low_, and had
become merged in the bank of light. At the time mentioned, the altitude
of Arcturus was 68° 30′, and, as Prof. Wheeler assigns only 10° as the
altitude of the bank, the maximum elevation of the arch, on the
supposition of its composing a part of the bank, was 43 miles. At
Perryville, the bank and streamers had disappeared at 10 o'clock. At
Ottawa, the arch or bow disappeared at 10 h. 5 m., differing only the
fraction of a minute from the time at Perryville; but, the bank was
still visible, but low and faint, the greatest altitude having been over
30°. To show the rapid fluctuations in width and position of this bow,
we will add a few of the minutes taken at the time with great care, in
hopes some other observer had been equally precise. When first seen,
there were three luminous patches, or elongated clouds of light; one in
Leo, one in Bootes, and another in Ophinchus, all in line. This was
about 9h. 15m. The times following are correct to 30 seconds:
9h. 42m. 30s. Bow complete; south edge 2° north of Arcturus.
9 45 30 Northern edge diffuse south; edge bright, and well
defined; 10° wide in zenith; north edge on Alphacca.
9 47 30 South edge 5° north of Arcturus; north edge close to
Cor. Caroli.
9 53 30 Eastern half composed of four detached bands
_shingling_ over each other.
58 30 Arcturus on south; bow narrower.
9 59 30 Arcturus in the middle of the band; very bright and
regular in outline, and widest at the zenith.
10 0 30 Arcturus on northern edge; north side better defined
than the southern.
10 2 0 Arcturus 1° north; very bright.
10 2 30 Gamma and Delta Leonis, northern edge.
10 3 Regulus on southern age; getting faint.
10 5 Fast fading away.
10 5 30 Scarcely visible; bank in north faint.
This aurora was due to the _inner vortex ascending_, whose period was at
this time 28 days.
There are several circumstances to be observed in this case. The bow
brightened and faded simultaneously with the aurora, and respected the
vertex of the auroral bank, being apparently concentric with it. The
bow, therefore, depends on the same cause, but differs from the aurora
in being limited to the _surface_ of the atmosphere in which the vortex
has produced a wave to the southward of its central path, as may be
understood by inspecting Fig. 2, Sec. 1,--the figure representing the
polar current of the central vortex. On the 29th of May, 1840,[32] the
author saw a similar phenomenon, at the same time of night, and passing
over the same stars southward until it reached within 5° of Jupiter and
Saturn, to which it was parallel. This atmospheric wave offers a greater
resistance to the passage of the ether: hence the light. On this account
it is, also, that when the passage of a vortex is attended by an auroral
display there will be no thunder-storm. There may be an increase of
wind; but the atmosphere at such times is too dry to make a violent
storm, and there is a silent restoration of the equilibrium, by the
ether passing through the dry atmosphere, without meeting any
condensable vapor, and becoming luminous on account of the greater
resistance of the air when unmixed with vapor. We thus see also the
connection between the aurora and the linear cirri, and we have a
triumphant explanation of the fact, that when the observer is north of
the northern limit of the vortices, he sees the aurora to the south and
not to the north; for, to see it to the northward, he would have to see
it in the same latitude as it appears in the south, and, consequently,
have to see across twice the complement of the latitude. We thus see,
also, why the temperature falls after an aurora; for, the passage of
electricity in any shape, must have this effect on account of the great
specific caloric of this fluid. We see, also, why the aurora should be
more frequent where the magnetic intensity is greatest and be
consequently invisible at the equator, and why the magnetic needle is so
sensibly affected at the time of its occurrence. We may, perhaps, here
be allowed to allude to another phenomenon connected with terrestrial
magnetism and electricity.
EARTHQUAKES.
The awful and destructive concussions which sometimes are produced at
great depths beneath the surface of the soil, would seem to indicate
that no force but that of electricity is adequate to account for the
almost instantaneous desolation of wide tracts of the earth's surface.
But we do not mean to say that the action of the terral vortices,
combined with the internal conditions of our planet, is the only cause;
although it is far from improbable that the same activity of the ether,
which generates through these vortices, the full fury of the hurricane
in the tropics, may be simultaneously accompanied by a _subterranean_
storm. And physicists are too rash to reject the evidence on which the
connection of the phenomena rests.
In the extract given by Colonel Reid, in his "Law of Storms," from Sir
George Rodney's official report of the great hurricane of 1780, it is
stated, that, "Nothing but an earthquake could have occasioned the
_foundations_ of the strongest buildings to be rent; and I am convinced
that the violence of the wind must have prevented the inhabitants from
feeling the earthquake which certainly attended the storm."[33] Again,
in the Savannah-la-Mar hurricane, which occurred the same year and
month, the Annual Register, published at Jamaica, states, that at the
same time, "a smart shock of an earthquake was felt." The general
serenity of equatorial regions is due to the fact that they are beyond
the limit of the vortices, as in Peru, where neither rain nor lightning
nor storm is ever seen. Thunder and rain, without storms, however, are
common in other tropical countries, also out of the reach of the
vortices. But even in those parts, (as the Antilles,) lying in the track
of these vortices, the weather is not as _frequently_ disturbed as in
higher latitudes. The storms of the Antilles, when they do occur,
however, are fearful beyond any conception, showing the presence of some
cause, auxiliary to the ordinary disturbing action of the vortices,
which, when simultaneously occurring, adds tremendously to their force.
That earthquakes are preceded _sometimes_ by a peculiar haziness and
oppressiveness, similar to that which sometimes precedes a storm, is a
current opinion in volcanic countries. And Humboldt, who doubts the
connection, has to confess that sudden changes of weather have
_succeeded_ violent earthquakes, and that "during the great earthquake
of Cumana, he found the inclination of the needle was diminished 48′."
He also mentions the simultaneous occurrence of shocks, from
earthquakes, and a clap of thunder, and the agitation of the
electrometer during the earthquake, which lasted from the 2d of April to
the 17th of May, 1808; but concluding that "these indications presented
by clouds, by modifications of atmospheric electricity, or by calms,
cannot be regarded as _generally_ or _necessarily_ connected with
earthquakes, since in Peru, Canada, and Italy, earthquakes are observed,
along with the purest and clearest skies, and with the freshest land and
sea breezes. But if no meteorological phenomena indicates the coming
earthquake, either on the morning of the shock or a few days previously,
the influence of certain periods of the year, (the vernal and autumnal
equinoxes,) the commencement of the rainy season in the tropics, after
long drought, cannot be overlooked, even though the genetic connection
of meteorological processes, with those going on in the interior of our
globe, is still enveloped in obscurity."[34]
It is at the equinoxes that the earth changes her distances from the sun
most rapidly, and whether she is passing from her perihelion or from
her aphelion, the density of the ether externally is changing in the
subduplicate ratio of these distances and consequently at these times
there will be the greatest disturbance of the electric equilibrium. How
far our views of the internal structure of our globe, (considered along
a diameter as a solid crust, then a fused mass separated from the lower
ocean by another solid crust, and separated from a similar arrangement
on the opposite side by an interposed mass of water, perhaps also
possessing a solid nucleus,) may affect this question, is difficult to
say; but that the agent is electric, appears highly probable; and very
recently it has been discovered, by M. Ratio Menton, that a piece of
iron, suspended by attraction to a magnet, will fall on the approach of
an earthquake; thus indicating that the power of the magnet is
temporarily weakened by the action of some disturbing force.
FOOTNOTES:
[22] Hum. Cosmos, art Aerolites.
[23] We shall in all cases use this abbreviation for the extremely
awkward word zodiacal.
[24] It is here assumed, that all the vortices are at their apogee at
the same time, and, consequently, they lie in different longitudes, but
the central being between, its position is taken for the average
position of the three.
[25] It is far from improbable that the effect produced in one zone of
climate, may be reversed in another, from the nature of the cause.
[26] That the 11th, 12th, and 13th of May should recede 2° in
temperature as determined by Mædler from observations of 86 years, at a
time when the power of the sun so rapidly augments, is strongly
confirmatory of the theory. See _Cosmos_, p. 121.
[27] Plucker first discovered that a plate of tourmaline suspended with
its axis vertical, set axial.
[28] Silliman's Journal for March and April, 1853.
[29] Humboldt, _Cosmos_ p. 193, London ed.
[30] See Silliman's Journal for September, 1853.
[31] See Silliman's Journal for September, 1853.
[32] This was the central vortex ascending.
[33] Reid's Law of Storms, p. 350.
[34] Humboldt, _Cosmos_, p. 203.
SECTION FOURTH.
THE SOLAR SPOTS.
We have yet many phenomena to investigate by the aid of the theory, and
we will develop them in that order which will best exhibit their mutual
dependence. The solar spots have long troubled astronomers, and to this
day no satisfactory solution of the question has been proposed; but we
shall not examine theories. It is sufficient that we can explain them on
the same general principles that we have applied to terrestrial
phenomena. There can be but little doubt about the existence of a solar
atmosphere, and, reasoning from analogy, the constituent elements of the
sun must partake of the nature of other planetary matter. That there are
bodies in our system possessing the same elements as our earth, is
proved by the composition of meteoric masses, which, whether they are
independent bodies of the system, or fragments of an exploded planet, or
projected from lunar volcanoes, is of little consequence; they show that
the same elements are distributed to other bodies of the system,
although not necessarily in the same proportions. The gaseous matter of
the sun's atmosphere may, therefore, be safely considered as vapors
condensable by cold, and the formation of vortices over the surface of
this atmosphere, brings down the ether, and causes it to intermingle
with this atmosphere. But, from the immensely rapid motion of the polar
current of the solar vortex, this ether may be considered to enter the
atmosphere of the sun with the temperature of space.
Sir John Herschel, in commenting on the theory of Mr. Redfield before
the British Association, convened at Newcastle in 1838,[35] suggested an
analogy to terrestrial hurricanes, from a suspected rotation and
progressive motion in these spots. From their rapid formation, change of
shape, and diameter, this view is allowable, and, taken in conjunction
with the action of the ethereal currents, will account for all the
phenomena. The nucleus of the spot is dense, like the nucleus of a storm
on the earth, and surrounded by a penumbon precisely as our storms are
fringed with lighter clouds, permitting the light of the sun to
penetrate. And, it has been observed, that these spots seem to follow
one another in lines on the same parallel of solar latitude (or nearly
the same), exactly as we have determined the action of the vortices on
the surface of the earth from observation. These spots are never found
in very high latitudes--not much above 30° from the solar equator. If we
consider this equator to be but slightly inclined to the plane of the
vortex, this latitude would be the general position of the lateral solar
vortices, and, in fact, be confined principally to a belt on each side
of the equator, between 15° and 30° of solar latitude, rather than at
the equator itself. This, it is needless to say, is actually the case.
But, a more capital feature still has been more recently brought to
light by observation, although previously familiar to the author, who,
in endeavoring to verify the theory, seriously injured his sight, by
observing with inadequate instrumental means. This is the periodicity of
the spots.
We have already observed, that there is reason to suppose that the
action of the inner vortex of the earth is probably greater than that of
the outer vortex, on account of the conflicting currents by which it is
caused. And the full development of this vortex requires, that the
central vortex or mechanical axis of the system shall be nearly
tangential to the surface. In this position, the action of the central
vortex is itself at a maximum; and, when the planets of the system are
so arranged as to produce this result, we may expect the greatest number
of spots. If the axis or central vortex approaches to coincidence with
the axis of the sun, the lateral vortices disappear, and the central
vortex being then perpendicular to the surface, is rendered ineffective.
Under these circumstances, there will be no spots on the sun's disc.
When, on the other hand, all the planets conspire at the same side to
force the sun out from the mechanical centre of the system, the surface
is too distant to be acted on by the central vortex, and the lateral
vortices are also thrown clear of the sun's surface, on account of the
greater velocity of the parts of the vortex, in sweeping past the body
of the sun. In this case, there will be but few spots. The case in which
the axis of the vortex coincides with the axis of the sun, is much more
transient than the first position, and hence, although the interval
between the maxima will be tolerably uniform, there will be an
irregularity between a particular maximum, and the preceding and
subsequent minimum.
The following table exhibits the solar spots, as determined by Schwabe,
of Dessau:
Year of observation. Groups of spots observed. Number of days.
1826 118 277
1827 161 273
1828 225 282
1829 199 244
1830 190 217
1831 149 239
1832 84 270
1833 33 267
1834 51 273
1835 173 244
1836 272 200
1837 333 168
1838 282 202
1839 162 205
1840 152 263
1841 102 283
1842 68 307
1843 34 324
Previous to the publication of this table, the author had inferred the
necessity of admitting the existence of another planet in the solar
system, from the phenomenon of which we are speaking. He found a
sufficient correspondence between the minima of spots to confirm the
explanation given by the theory, and this was still more confirmed by
the more exact determination of Schwabe; yet there was a little
discrepancy in the synchronous values of the ordinates, when the theory
was graphically compared with the table. Previous to the discovery of
Neptune, the theory corresponded much better than afterwards, and as no
doubt could be entertained that the anomalous movements of Uranus were
caused by an exterior planet, he adopted the notion that there were two
planets exterior to Uranus, whose positions at the time were such, that
their mechanical affects on the system were about equal and contrary.
Consequently, when Neptune became known, the existence of another planet
seemed a conclusion necessary to adopt. Accordingly, he calculated the
heliocentric longitudes and true anomalies, and the values of radius
vector, for all the planets during the present century, but not having
any planetary tables, he contented himself with computing for the
nearest degree of true anomaly, and the nearest thousand miles of
distance. Then by a composition and resolution of all the forces, he
deduced the radius vector of the sun, and the longitude of his centre,
for each past year of the century. It was in view of a little
outstanding discrepancy in the times of the minima, as determined by
theory and observation, that he was induced to consider as almost
certain the existence of a theoretical planet, whose longitude, in 1828,
was about 90°, and whose period is from the theory about double that of
Neptune. And for convenience of computation and reference, he has been
in the habit of symbolizing it by a volcano. The following table of the
radii vectores of the sun, and the longitude of his centre, for the
years designated in Schwabe's table, is calculated from the following
data for each planet:
Long. of
Planets. Masses. Mean distances. Eccentricities. Perihelion.
♃ 1/1648 494.800.000 0.0481 11°
♄ 1/3310 907.162.000 0.0561 89
♅ 1/23000 1824.290.000 0.0166 167
♆ 1/20000 2854.000.000 0.0088 0
⊿ 1/28000 4464.000.000
No. of spots in
Dates. Rad. vector. Sun's long. Ordinates. Schwabe's table.
Jan. 1, 1826 528,000 320° + 84 118
" 1827 480,000 339 + 36 161
" 1828 432,000 352 - 12 Max. 225 Max.
" 1829 397,000 38 - 47 199
" 1830 858,000 71 - 86 190
" 1831 324,000 104 - 120 149
" 1832 311,000 144 - 133 84
" 1833 300,000 183 - 144 Min. 33 Min.
" 1834 307,000 220 - 137 51
" 1835 338,000 263 - 106 173
" 1836 380,000 302 - 55 272
" 1837 419,000 337 + 25 Max. 333 Max.
" 1838 488,000 3 + 44 282
" 1839 651,000 29 + 107 162
" 1840 632,000 51 + 188 152
" 1841 680,000 80 + 236 102
" 1842 730,000 105 + 286 68
" 1843 160,000 128 + 322 34 Min.
" 1844 188,000 152 + 339 Min. 52
" 1845 772,000 174 + 328 114
" 1846 728,000 196 + 284 157
" 1847 660,000 218 + 216
" 1848 563,000 240 + 119 Observed. Max.
" 1849 447,000 261 + 3 Max.
" 1850 309,000 283 - 135
" 1851 170,000 323 - 274
" 1852 53,000 41 - 391 Min.
" 1853 167,000 133 - 277
" 1854 315,000 160 - 129
" 1855 475,000 183 + 31 Max.
" 1856 611,000 203 + 167
" 1857 720,000 225 + 276
It is necessary to observe here, that the values of the numbers in
Schwabe's table are the numbers for the whole year, and, therefore, the
1st of July would have been a better date for the comparison; but, as
the table was calculated before the author was cognizant of the fact,
and being somewhat tedious to calculate, he has left it as it was, viz.,
for January 1st of each year. Hence, the minimum for 1843 appears as
pertaining to 1844. The number of spots ought to be inversely as the
ordinates approximately--these last being derived from the Radii
Vectores minus, the semi-diameter of the sun = 444,000 miles.
In passing judgment on this relation, it must also be borne in mind,
that the recognized masses of the planets cannot be the true masses, if
the theory be true. Both sun and planets are under-estimated, yet, as
they are, probably, all to a certain degree proportionally undervalued,
it will not vitiate the above calculation much.
The spots being considered as solar storms, they ought also to vary in
number at different times of the year, according to the longitude of the
earth and sun, and from their transient character, and the slow rotation
of the sun, they ought, _ceteris paribus_, to be more numerous when the
producing vortex is over a visible portion of the sun's surface.
The difficulty of reconciling the solar spots, and their periodicity to
any known principle of physics, ought to produce a more tolerant spirit
amongst the scientific for speculations even which may afford the
slightest promise of a solution, although emanating from the humblest
inquirer after truth. The hypothesis of an undiscovered planet, exterior
to Neptune, is of a nature to startle the cautions timidity of many;
but, if the general theory be true, this hypothesis becomes extremely
probable. We may not have located it exactly. There may be even two such
planets, whose joint effect shall be equivalent to one in the position
we have assigned. There may even be a comet of great mass, capable of
producing an effect on the position of the sun's centre (although it
follows from the theory that comets have very little mass). Yet, in view
of all these suppositions, there can be but little doubt that the solar
spots are caused by the solar vortices, and these last made effective on
the sun by the positions of the great planets, and, therefore, we have
indicated a new method of determining the existence and position of all
the planets exterior to Neptune. On the supposition that there is only
one more in the system, from its deduced distance and mass, it will
appear only as a star of the eleventh magnitude, and, consequently, will
only be recognizable by its motion, which, at the greatest, will only be
ten or eleven seconds per day.
MASSES OF THE SUN AND PLANETS.
We have alluded to the fact of the radial stream of the sun necessarily
diminishing the sun's power, and, consequently, diminishing his apparent
mass. The radial stream of all the planets will do the same, so that
each planet whose mass is derived from the periodic times of the
satellites, will also appear too small. But, there is also a great
probability that some modification must be made in the wording of the
Newtonian law. The experiments of Newton on the pendulum, with every
variety of substance, was sufficient justification to entitle him to
infer, that inertia was as the weight of matter universally. But, there
was one condition which could not be observed in experimenting on these
substances, viz., the difference of temperature existing between the
interior and surface of a planet.
We have already expressed the idea, that the cause of gravity has no
such mysterious origin as to transcend the power of man to determine it.
But that, on the contrary, we are taught by every analogy around us, as
well as by divine precept, to use the visible things of creation as
stepping stones to the attainment of what is not so apparent. That we
have the volume of nature spread out in tempting characters, inviting us
to read, and, assuredly, it is not so spread in mockery of man's limited
powers. As science advances, strange things, it is true, are brought to
light, but the more _rational_ the queries we propound, in every case
the more satisfactory are the answers. It is only when man consults the
oracle in irrational terms that the response is ambiguous. Alchemy, with
its unnatural transmutations, has long since vanished before the
increasing light. Why should not attraction also? Experience and
experiment, if men would only follow their indications, are consistently
enforcing the necessity of erasing these antiquated chimeras from the
book of knowledge; and inculcating the great truth, that the physical
universe owes all its endless variety to differences in the form, size,
and density of planetary atoms in motion, according to simple mechanical
principles. These, combined with the existence of an all-pervading
medium filling space, between which and planetary matter no bond of
union subsists, other than that which arises from a continual
interchange of motion, are the materials from which the gems of nature
are elaborated. But, simplicity of means is what philosophy has ever
been reluctant to admit, preferring rather the occult and obscure.
If action be equal to reaction, and all nature be vibrating with motion,
these motions must necessarily interfere, and some effect should be
produced. A body radiating its motion on every side into a physical
medium, produces waves. These waves are a mechanical effect, and the
body parts with some of its motion in producing them; but, should
another body be placed in juxtaposition, having the same motion, the
opposing waves neutralize each other, and the bodies lose no motion from
their contiguous sides, and, therefore, the reaction from the opposite
sides acts as a propelling power, and the bodies approach, or tend to
approach each other. If one body be of double the inertia, it moves only
half as far as the first; then, seeing that this atomic motion is
radiated, the law of force must be directly as the mass, and inversely
as the squares of the distances. There may be other atomic vibrations
besides those which we call light, heat, and chemical action, yet the
joint effect of all is infinitesimally small, when we disregard the
united _attraction_ of all the atoms of which the earth is composed. The
_attraction_ of the whole earth at the surface causes bodies to fall 16
feet the first second of time; but, if two spheres of ice of one foot
diameter, were placed in an infinite space, uninfluenced by other
matter, and only 16 feet apart, they would require nearly 10,000 years
to fall together by virtue of their mutual attraction. Our conceptions,
or, rather, our misconceptions, concerning the force of gravity, arises
from our forgetting that every pound of matter on the earth contributes
its share of the force which, in the aggregate, is so powerful. Hence,
the cause we have suggested, is fully adequate to account for the
phenomena. Whether the harmony of vibrations between two bodies may not
have an influence in determining the amount of interference, and,
consequently, produce _some_ difference between the gravitating mass
and its inertia, is a question which, no doubt, will ultimately be
solved; but this harmony of vibrations must depend, in some degree, on
the atomic weight, temperature, and intensity of atomic motion.
That a part of the mass of the earth is _latent_ may be inferred from
certain considerations: 1st, from the discrepancies existing in the
results obtained for the earth's compression by the pendulum and by
actual measurement; and, 2d, from the irregularity of that compression
in particular latitudes and longitudes. The same may also be deduced
from the different values of the moon's mass as derived from different
phenomena, dependent on the law of gravitation. Astronomers have
hitherto covered themselves with the very convenient shield of errors of
observation; but, the perfection of modern instruments now demand a
better account of all outstanding discrepancies. The world requires it
of them.
The mass of the moon comes out much greater by our theory than nutation
gives. The mass deduced from the theory is only dependent on the
relative inertiæ of the earth and moon. That given by nutation depends
on gravity. If, then, a part of the mass be latent, nutation will give
too small a value. But, in addition to this, we are justified in
doubting the strict wording of the Newtonian law, deriving our authority
from the very foundation stone of the Newtonian theory.
It is well known that Newton suspected that the moon was retained in her
orbit by the same force which is usually called weight upon the surface,
sixteen years before the fact was confirmed, by finding a correspondence
in the fall of the moon and the fall of bodies on the earth. Usually, in
all elementary works, this problem is considered accurately solved.
Having formed a different idea of the mechanism of nature, this fact
presented itself as a barrier beyond which it was impossible to pass,
until suspicions, derived from other sources, induced the author to
inquire: Whether the phenomenon did exactly accord with the theory? We
are aware that it is easy to place the moon at such a distance, that the
result shall strictly correspond with the fact; but, from the parallax,
as derived from observation (and if this cannot be depended on
certainly, no magnitudes in astronomy can), we find, _that the moon does
not fall from the tangent of her orbit, as much as the theory requires_.
As this is of vital importance to the integrity of the theory we are
advocating, we have made the computation on Newton's own data, except
such as were necessarily inaccurate at the time he wrote; and we have
done it arithmetically, without logarithmic tables, that, if possible,
no error should creep in to vitiate the result. We take the moon's
elements from no less an authority than Sir John Herschel, as well as
the value of the earth's diameter.
Mass of the moon 1/80
Mean distance in equatorial radii 59.96435
Sidereal period in seconds 2360591
The vibrations of the pendulum give the force of gravity at the surface
of the earth, and it is found to vary in different latitudes. The
intensity in any place being as the squares of the number of vibrations
in a given time. This inequality depends on the centrifugal force of
rotation, and on the spheroidal figure of the earth due to that
rotation. At the equator the fall of a heavy body is found to be
16.045223 feet, per second, and in that latitude the squares of whose
sine is ⅓, it is 16.0697 feet. The effect in this last-named latitude
is the same as if the earth were a perfect sphere. This does not,
however, express the whole force of gravity, as the rotation of the
earth causes a centrifugal tendency which is a maximum at the equator,
and there amounts to 1/289 of the whole gravitating force. In other
latitudes it is diminished in the ratio of the squares of the cosines of
the latitude; it therefore becomes 1/434 in that latitude the square of
whose sine is ⅓. Hence the fall per second becomes 16.1067 feet for
the true gravitating force of the earth, or for that force which retains
the moon in her orbit.
The moon's mean distance is 59.96435 equatorial radii of the earth,
which radius is, according to Sir John Herschel, 20.923.713
feet. Her mean distance as derived from the parallax is not to be
considered the radius vector of the orbit, inasmuch as the earth also
describes a small orbit around the common centre of gravity of the earth
and moon; neither is radius vector to be considered as her distance from
this common centre; for the attracting power is in the centre of the
earth. But the mean distance of the moon moving around a movable centre,
is to the same mean distance when the centre of attraction is fixed, as
the sum of the masses of the two bodies, to the first of two mean
proportionals between this sum and the largest of the two bodies
inversely. (Vid. Prin. Prop. 60 Lib. Prim.) The ratio of the masses
being as above 80 to 1 the mean proportional sought is 80.666 and in
this ratio must the moon's mean distance be diminished to get the force
of gravity at the moon. Therefore as 81 is to 80.666, so is 59.96435 to
59.71657 for the moon's distance in equatorial radii of the earth.
Multiply this last by 20.923,713 to bring the semi-diameter of the lunar
orbit into feet = 1.249.492.373, and this by 6.283185, the ratio of the
circumference to the radius, gives 7.850.791.736 feet, for the mean
circumference of the lunar orbit.
Further, the mean sidereal period of the moon is 2360591 seconds and the
1/2360591th part of 7.850.791.736 is the arc the moon describes in one
second = 3325.77381 feet, the square of which divided by the diameter
of the orbit, gives the fall of the moon from the tangent or versed
size of that arc.
1106771.36876644
= ---------------- = 0.004426106 feet.
2498984746
This fraction is, however, too small, as the ablatitious action of the
sun diminishes the attraction of the earth on the moon, in the ratio of
178 29/40 to 177 29/40. So that we must increase the fall of the moon
in the ratio of 711 to 715, and hence the true fall of the moon from the
tangent of her orbit becomes 0.00451 feet per second.
We have found the fall of a body at the surface of the earth, considered
as a sphere, 16.1067 feet per second, and the force of gravity
diminishes as the squares of the distances increases. The polar diameter
of the earth is set down as 7899.170 miles, and the equatorial diameter
7925.648 miles; therefore, the mean diameter is 7916.189 miles.[36] So
that, reckoning in mean radii of the earth, the moon's distance is
59.787925, which squared, is equal to 3574.595975805625. At one mean
radius distance, that is, at the surface, the force of gravity, or fall
per second, is as above, 16.1067 feet. Divide this by the square of the
distance, it is 16.1067/3574.595975805625 = 0.0045058 feet for the force
of gravity at the moon. But, from the preceding calculation, it appears,
that the moon only falls 0.0044510 feet in a second, showing a
deficiency of 1/82d part of the principal force that retains the moon in
her orbit, being more than double the whole disturbing power of the sun,
which is only 1/178th of the earth's gravity at the moon; yet, on this
1/178th depends the revolution of the lunar apogee and nodes, and all
those variations which clothe the lunar theory with such formidable
difficulties. The moon's mass cannot be less than 1/80, and if we
consider it greater, as it no doubt is, the results obtained will be
still more discrepant. Much of this discrepancy is owing to the
expulsive power of the radial stream of the terral vortex; yet, it may
be suspected that the effect is too great to be attributed to this, and,
for this reason, we have suggested that the fused matter of the moon's
centre may not gravitate with the same force as the exterior parts, and
thus contribute to increase the discrepancy.
As there must be a similar effect produced by the radial stream of every
vortex, the masses of all the planets will appear too small, as derived
from their gravitating force; and the inertia of the sun will also be
greater than his apparent mass; and if, in addition to this, there be a
portion of these masses latent, we shall have an ample explanation of
the connection between the planetary densities and distances. We must
therefore inquire what is the particular law of force which governs the
radial stream of the solar vortex. It will be necessary to enter into
this question a little more in detail than our limits will justify; but
it is the resisting influence of the ether, and its consequences, which
will appear to present a vulnerable point in the present theory, and to
be incompatible with the perfection of astronomical science.
LAW OF DENSITY IN SOLAR VORTEX.
Reverting to the dynamical principle, that the product of every particle
of matter in a fluid vortex, moving around a given axis, by its distance
from the centre and angular velocity, must ever be a constant quantity,
it follows that if the ethereal medium be uniformly dense, the periodic
times of the parts of the vortex will be directly as the distances from
the centre or axis; but the angular velocities being inversely as the
times, the absolute velocities will be equal at all distances from the
centre.
Newton, in examining the doctrine of the Cartesian vortices, supposes
the case of a globe in motion, gradually communicating that motion to
the surrounding fluid, and finds that the periodic times will be in the
duplicate ratio of the distances from the centre of the globe. He and
his successors have always assumed that it was impossible for the
principle of gravity to be true, and a Cartesian plenum also;
consequently, the question has not been fairly treated. It is true that
Descartes sought to explain the motions of the planets, by the
mechanical action of a fluid vortex _solely_; and to Newton belongs the
glorious honor of determining, the existence of a centripetal force,
competent to explain these motions mathematically, (but not physically,)
and rashly rejected an intelligible principle for a miraculous virtue.
If our theory be true, the visible creation depends on the existence of
both working together in harmony, and that a physical medium is
absolutely necessary to the existence of gravitation.
If space be filled with a fluid medium, analogy would teach us that it
is in motion, and that there must be inequalities in the direction and
velocity of that motion, and consequently there must be vortices. And if
we ascend into the history of the past, we shall find ample testimony
that the planetary matter now composing the members of the solar system,
was once one vast nebulous cloud of atoms, partaking of the vorticose
motion of the fluid involving them. Whether the gradual accumulation of
these atoms round a central nucleus from the surrounding space, and thus
having their tangential motion of translation converted into vorticose
motion, first produced the vortex in the ether; or whether the vortex
had previously existed, in consequence of conflicting currents in the
ether, and the scattered atoms of space were drawn into the vortex by
the polar current, thus forming a nucleus at the centre, as a necessary
result of the eddy which would obtain there, is of little consequence.
The ultimate result would be the same. A nucleus, once formed, would
give rise to a central force, tending more and more to counteract the
centripulsive power of the radial stream; and in consequence of this
continually increasing central power, the heaviest atoms would be best
enabled to withstand the radial stream, while the lighter atoms might be
carried away to the outer boundaries of the vortex, to congregate at
leisure, and, after the lapse of a thousand years, to again face the
radial stream in a more condensed mass, and to force a passage to the
very centre of the vortex, in an almost parabolic curve. That space is
filled with isolated atoms or planetary dust, is rendered very probable
by a fact discovered by Struve, that there is a gradual extinction in
the light of the stars, amounting to a loss of 1/107 of the whole, in
the distance which separates Sirius from the sun. According to Struve,
this can be accounted for, "by admitting as very probable that space is
filled with an _ether_, capable of intercepting in some degree the
light." Is it not as probable that this extinction is due to planetary
dust, scattered through the pure ether, whose vibrations convey the
light,--the material atoms of future worlds,--the debris of dilapidated
comets? Does not the Scripture teach the same thing, in asserting that
the heavens are not clean?
The theory of vortices has had many staunch supporters amongst those
deeply versed in the science of the schools. The Bernoullis proposed
several ingenious hypothesis, to free the Cartesian system from the
objections urged against it, viz.: that the velocities of the planets,
in accordance with the three great laws of Kepler, cannot be made to
correspond with the motion of a fluid vortex; but they, and all others,
gave the vantage ground to the defenders of the Newtonian philosophy, by
seeking to refer the principle of gravitation to conditions dependent on
the density and vorticose motion of the ether. When we admit that the
ether is imponderable and yet material, and planetary matter subject to
the law of gravitation, the objections urged against the theory of
vortices become comparatively trivial, and we shall not stop to refute
them, but proceed with the investigation, and consider that the ether is
the original source of the planetary motions and arrangements.
On the supposition that the ether is uniformly dense, we have shown that
the periodic times will be directly as the distances from the axis. If
the density be inversely as the distances, the periodic times will be
equal. If the density be inversely as the square roots of the distances,
the times will be directly in the same ratio. The celebrated J.
Bernoulli assumed this last ratio; but seeking the source of motion in
the rotating central globe, he was led into a hypothesis at variance
with analogy. The ellipticity of the orbit, according to this view,
was caused by the planet oscillating about a mean position,--sinking
first into the dense ether,--then, on account of superior buoyancy,
rising into too light a medium. Even if no other objection could be
urged to this view, the difficulty of explaining why the ether should be
denser near the sun, would still remain. We might make other
suppositions; for whatever ratio of the distances we assume for the
density of the medium, the periodic times will be compounded of those
distances and the assumed ratio. Seeing, therefore, that the periodic
times of the planets observe the direct ses-plicate ratio of the
distances, and that it is consonant to all analogy to suppose the
contiguous parts of the vortex to have the same ratio, we find that the
density of the ethereal medium in the solar vortex, is directly as the
square roots of the distances from the axis.
Against this view, it may be urged that if the inertia of the medium is
so small, as is supposed, and its elasticity so great, there can be no
condensation by centrifugal force of rotation. It is true that when we
say the ether is condensed by this force, we speak incorrectly. If in an
infinite space of imponderable fluid a vortex is generated, the central
parts are rarefied, and the exterior parts are unchanged. But in all
finite vortices there must be a limit, outside of which the motion is
null, or perhaps contrary. In this case there may be a cylindrical ring,
where the medium will be somewhat denser than outside. Just as in water,
every little vortex is surrounded by a circular wave, visible by
reflection. As the density of the planet Neptune appears, from present
indications, to be a little denser than Uranus, and Uranus is denser
than Saturn, we may conceive that there is such a wave in the solar
vortex, near which rides this last magnificent planet, whose ring would
thus be an appropriate emblem of the peculiar position occupied by
Saturn. This may be the case, although the probability is, that the
density of Saturn is much greater than it appears, as we shall presently
explain.
In order to show that there is nothing extravagant in the supposition of
the density of the ether being directly as the square roots of the
distances from the axis, we will take a fluid whose law of density is
known, and calculate the effect of the centrifugal force, considered as
a compressing power. Let us assume our atmosphere to be 47 miles high,
and the compressing power of the earth's gravity to be 289 times greater
than the centrifugal force of the equator, and the periodic time of
rotation necessary to give a centrifugal force at the equator equal to
the gravitating force to be 83 minutes. Now, considering the gravitating
force to be uniform, from the surface of the earth upwards, and knowing
from observation that at 18,000 feet above the surface, the density of
the air is only ½, it follows, (in accordance with the principle that
the density is as the compressing force,) that at 43½ miles high, or
18,000 feet _below_ the surface of the atmosphere, the density is only
1/8000 part of the density at the surface of the earth. Let us
take this density as being near the limit of expansion, and conceive a
hollow tube, reaching from the sun to the orbit of Neptune, and that
this end of the tube is closed, and the end at the sun communicates with
an inexhaustible reservoir of such an attenuated gas as composes the
upper-layer of our atmosphere; and further, that the tube is infinitely
strong to resist pressure, without offering resistance to the passage of
the air within the tube; then we say, that, if the air within the tube
be continually acted on by a force equal to the mean centrifugal force
of the solar vortex, reckoning from the sun to the orbit of Neptune, the
density of the air at that extremity of the tube, would be greater than
the density of a fluid formed by the compression of the ocean into one
single drop. For the centrifugal force of the vortex at 2,300,000 miles
from the centre of the sun, is equal to gravity at the surface of the
earth, and taking the mean centrifugal force of the whole vortex as
one-millionth of this last force; so that at 3,500,000 miles from the
surface of the sun, the density of the air in the tube (supposing it
obstructed at that distance) would be double the density of the
attenuated air in the reservoir. And the air at the extremity of the
tube reaching to the orbit of Neptune, would be as much denser than the
air we breathe, as a number expressed by 273 with 239 ciphers annexed,
is greater than unity. This is on the supposition of infinite
compressibility. Now, in the solar vortex there is no physical barrier
to oppose the passage of the ether from the centre to the circumference,
and the density of the ethereal ocean must be considered uniform, except
in the interior of the stellar vortices, where it will be rarefied; and
the rarefaction will depend on the centrifugal force and the length of
the axis of the vortex. If this axis be very long, and the centrifugal
velocity very great, the polar influx will not be sufficient, and the
central parts will be rarefied. We see, therefore, no reason why the
density of the ether may not be three times greater at Saturn than at
the earth, or as the square roots of the distances directly.
BODES' LAW OF PLANETARY DISTANCES.
Thus, in the solar vortex, there will be two polar currents meeting at
the sun, and thence being deflected at right angles, in planes parallel
to the central plane of the vortex, and strongest in that central plane.
The velocity of expansion must, therefore, diminish from the divergence
of the radii, as the distances increase; but in advancing along these
planes, the ether of the vortex is continually getting more dense,
which operate by absorption or condensation on the radial stream; so
that the velocity is still more diminished, and this in the ratio of the
square roots of the distances directly. By combining these two ratios,
we find that the velocity of the radial stream will be in the
ses-plicate ratio of the distances inversely. But the force of this
stream is not as the velocity, but as the square of the velocity. The
_force_ of the radial stream is consequently as the cubes of the
distances inversely, from the axis of the vortex, reckoned in the same
plane. If the ether, however, loses in velocity by the increasing
density of the medium, it becomes also more dense; therefore the true
force of the radial stream will be as its density and the square of its
velocity, or directly as the square roots of the distances, and
inversely as the cubes of the distances, or as the 2.5 power of the
distances inversely.
If we consider the central plane of the vortex as coincident with the
plane of the ecliptic, and the planetary orbits, also, in the same
plane; and had the force of the radial stream been inversely as the
square of the distances, there could be no disturbance produced by the
action of the radial stream. It would only counteract the gravitation of
the central body by a certain amount, and would be exactly proportioned
at all distances. As it is, there is an outstanding force as a
disturbing force, which is in the inverse ratio of the square roots of
the distances from the sun; and to this is, no doubt, owing, in part,
the fact, that the planetary distances are arranged in the inverse order
of their densities.
Suppose two planets to have the same diameter to be placed in the same
orbit, they will only be in equilibrium when their densities are equal.
If their densities are unequal, the lighter planet will continually
enlarge its orbit, until the force of the radial stream becomes
proportional to the planets' resisting energy. This, however, is on the
hypothesis that the planets are not permeable by the radial stream,
which, perhaps, is more consistent with analogy than with the reality.
And it is more probable that the mean atomic weight of a planet's
elements tends more to fix the position of equilibrium for each. Under
the law of gravity, a planet may revolve at any distance from the sun,
but if we superadd a centripulsive force, whose law is not that of
gravity, but yet in some inverse ratio of the distances, and this force
acts only superficially, it would be possible to make up in volume what
is wanted in density, and a lighter planet might thus be found occupying
the position of a dense planet. So the planet Jupiter, respecting only
his resisting surface, is better able to withstand the force of the
radial stream at the earth than the earth itself. To understand this, it
is necessary to bear in mind, that, as far as planetary matter is
concerned, the earth would revolve in Jupiter's orbit in the same
periodic time as Jupiter, under the law of gravity: but that, in
reality, the whole of the gravitating force is not effective, and that
the equilibrium of a planet is due to a nice balance of interfering
forces arising from the planet's physical peculiarities. As in a
refracting body, the density of the ether may be considered inversely as
the refraction, and this as the atomic weight of the refracting
material, so, also, in a planet, the density of the ether will be
inversely in the same ratio of the density of the matter approximately.
Hence, the density of the ether within the planet Jupiter is greater
than that within the earth; and, on this ethereal matter, the sun has no
power to restrain it in its orbit, so that the centrifugal momentum of
Jupiter would be relatively greater than the centrifugal momentum of the
earth, were it also in Jupiter's orbit with the same periodic time.
Hence, to make an equilibrium, the earth should revolve in a medium of
less density, that there may be the same proportion between the external
ether, and the ether within the earth, as there is between the ether
around Jupiter and the ether within; so that the centrifugal tendency of
the dense ether at Jupiter shall counteract the greater momentum of the
dense ether within Jupiter; or, that the lack of centrifugal momentum in
the earth should be rendered equal to the centrifugal momentum of
Jupiter, by the deficiency of the centrifugal momentum of the ether at
the distance of the earth.
If then, the diameters of all the planets were the same (supposing the
ether to act only superficially), the densities would be as the
distances inversely;[37] for the force due to the radial stream is as
the square roots of the distance inversely, and the force due to the
momentum, if the density of the ether within a planet be inversely as
the square root of a planet's distance, will also be inversely as the
square roots of the distances approximately. We offer these views,
however, only as suggestions to others more competent to grapple with
the question, as promising a satisfactory solution of Bode's empirical
formula.
If there be a wave of denser ether cylindrically disposed around the
vortex at the distance of Saturn, or between Saturn and Uranus, we see
why the law of densities and distances is not continuous. For, if the
law of density changes, it must be owing to such a ring or wave. Inside
this wave, the two forces will be inverse; but outside, one will be
inverse, and the other direct: hence, there should also be a change in
the law of distances. As this change does not take place until we pass
Uranus, it may be suspected that the great disparity in the density of
Saturn may be more apparent than real. The density of a planet is the
relation between its mass and volume or extension, no matter what the
form of the body may be. From certain observations of Sir Wm.
Herschel--the Titan of practical astronomers--the figure of Saturn was
suspected to be that of a square figure, with the corners rounded off,
so as to leave both the equatorial and polar zones flatter than
pertained to a true spheroidal figure. The existence of an unbroken ring
around Saturn, certainly attaches a peculiarity to this planet which
prepares us to meet other departures from the usual order. And when we
reflect on the small density, and rapid rotation, the formation of this
ring, and the figure suspected by Sir Wm. Herschel, it is neither
impossible nor improbable, that there may be a cylindrical vacant space
surrounding the axis of Saturn, or at least, that his solid parts may be
cylindrical, and his globular form be due to elastic gases and vapors,
which effectually conceal his polar openings. And also, by dilating and
contracting at the poles, in consequence of inclination to the radial
stream, (just as the earth's atmosphere is bulged out sufficiently to
affect the barometer at certain hours every day,) give that peculiarity
of form in certain positions of the planet in its orbit. Justice to Sir
Wm. Herschel requires that _his_ observations shall not be attributed to
optical illusions. This view, however, which may be true in the case of
Saturn, would be absurd when applied to the earth, as has been done
within the present century. From these considerations, it is at least
possible, that the density of Saturn may be very little less, or even
greater than the density of Uranus, and be in harmony with the law of
distances.
It is now apparently satisfactorily determined, that Neptune is denser
than Uranus, and the law being changed, we must look for transneptunean
planets at distances corresponding with the new law of arrangement. But
there are other modifying causes which have an influence in fixing the
precise position of equilibrium of a planet. Each planet of the system
possessing rotation, is surrounded by an ethereal vortex, and each
vortex has its own radial stream, the force of which in opposing the
radial stream of the sun, depends on the diameter and density of the
planet, on the velocity of rotation, on the inclination of its axis, and
on the density of the ether at each particular vortex; but the numerical
verification of the position of each planet with the forces we have
mentioned, cannot be made in the present state of the question. There is
one fact worthy of note, as bearing on the theory of vortices in
connection with the rotation of the planets, viz.: that observation has
determined that the axial rotation and sidereal revolution of the
secondaries, are identical; thus showing that they are without vortices,
and are motionless relative to the ether of the vortex to which they
belong. We may also advert to the theory of Doctor Olbers, that the
asteroidal group, are the fragments of a larger planet which once
filled the vacancy between Mars and Jupiter. Although this idea is not
generally received, it is gathering strength every year by the discovery
of other _fragments_, whose number now amounts to twenty-six. If the
idea be just, our theory offers an explanation of the great differences
observable in the mean distances of these bodies, and which would
otherwise form a strong objection against the hypothesis. For if these
little planets be fragments, there will be differences of density
according as they belonged to the central or superficial parts of the
quondam planet, and their mean distances must consequently vary also.
There are some other peculiarities connecting the distances and
densities, to which we shall devote a few words. In the primordial state
of the system, when the nebulous masses agglomerated into spheres, the
diameter of these nebulous spheres would be determined by the relation
existing between the rotation of the mass, and the gravitating force at
the centre; for as long as the centrifugal force at the equator exceeded
the gravitating force, there would be a continual throwing off of matter
from the equator, as fast as it was brought from the poles, until a
balance was produced. It is also extremely probable, (especially if the
elementary components of water are as abundant in other planets as we
have reason to suppose them to be on the earth,) that the condensation
of the gaseous planets into liquids and solids, was effected in a _brief
period of time_,[38] leaving the lighter and more elastic substances as
a nebulous atmosphere around globes of semi-fluid matter, whose
diameters have never been much increased by the subsequent condensation
of their gaseous envelopes. The extent of these atmospheres being (in
the way pointed out) determined by the rotation, their subsequent
condensation has not therefore changed the original rotation of the
central globe by any appreciable quantity. The present rotation of the
planets, is therefore competent to determine the former diameters of the
nebulous planets, _i.e._, the limit where the present central force
would be balanced by the centrifugal force of rotation. If we make the
calculation for the planets, and take for the unit of each planet its
present diameter, we shall find that they have condensed from their
original nebulous state, by a quantity dependent on the distance, from
the centre of the system; and therefore on the original temperature of
the nebulous mass at that particular distance. Let us make the
calculation for Jupiter and the earth, and call the original nebulous
planets the nucleus of the vortex. We find the Equatorial diameter of
Jupiter's nucleus in equatorial diameters of Jupiter = 2.21, and the
equatorial diameter of the earth's nucleus, in equatorial diameters of
the earth = 6.59. Now, if we take the original temperature of the
nebulous planets to be inversely, as the squares of the distances from
the sun, and their volumes directly as the cubes of the diameters in the
unit of each, we find that these cubes are to each other, in the inverse
ratio of the squares of the planet's distances; for,
2.21³ : 6.59³ :: 1² : 5.2²,
showing that both planets have condensed equally, allowing for the
difference of temperature at the beginning. And we shall find, beginning
at the sun, that the diameters of the nebulous planets, _ceteris
paribus_, diminish outwards, giving for the nebulous sun a diameter of
16,000,000 miles,[39] thus indicating his original great temperature.
That the original nebulous planets did rotate in the same time as they
do at present, is proved by Saturn's ring; for if we make the
calculation, about twice the diameter of Saturn. Now, the diameter of
the planet is about 80,000 miles, which will also be the semi-diameter
of the nebulous planet; and the middle of the outer ring has also a
semi-diameter of 80,000 miles; therefore, the ring is the equatorial
portion of the original nebulous planet, and ought, on this theory, to
rotate in the same time as Saturn. According to Sir John Herschel,
Saturn rotates in 10 hours, 29 minutes, and 17 seconds, and the ring
rotates in 10 hours, 29 minutes, and 17 seconds: yet this is not the
periodic time of a satellite, at the distance of the middle of the ring;
neither ought the rings to rotate in the same time; yet as far as
observation can be trusted, both the inner and outer ring do actually
rotate in the same time. The truth is, the ring rotates too fast, if we
derive its centrifugal force from the analogy of its satellites; but it
is, no doubt, in equilibrium; and the effective mass of Saturn on the
satellites is less than the true mass, in consequence of his radial
stream being immensely increased by the additional force impressed on
the ether, by the centrifugal velocity of the ring. If this be so, the
mass of Saturn, derived from one of the inner satellites, will be less
than the same mass derived from the great satellite, whose orbit is
considerably inclined. The analogy we have mentioned, between the
diameters of the nebulous planets and their distances, does not hold
good in the case of Saturn, for the reason already assigned, viz.: that
the nebulous planet was probably not a globe, but a cylindrical ring,
vacant around the axis, as there is reason to suppose is the case at
present.
And now we have to ask the question, Did the ether involved in the
nebulous planets rotate in the same time? This does not necessarily
follow. The ether will undoubtedly tend to move with increasing velocity
to the very centre of motion, obeying the great dynamical principle when
unresisted. If resisted, the law will perhaps be modified; but in this
case, its motion of translation will be converted into atomic motion or
heat, according to the motion lost by the resistance of atomic matter.
This question has a bearing on many geological phenomena. As regards the
general effect, however, the present velocity of the ether circulating
round the planets, may be considered much greater than the velocities of
the planets themselves.
PERTURBATIONS DUE TO THE ETHER.
In these investigations it is necessary to bear in mind that the whole
resisting power of the ether, in disturbing the planetary movements, is
but small, in comparison with gravitation. We will, however, show that,
in the case of the planets, there is a compensation continually made by
this resistance, which leaves but a very small outstanding balance as a
disturbing power. If we suppose all the planets to move in the central
plane of the vortex in circular orbits, and the force of the radial
stream, (or that portion which is not in accordance with the law of
gravitation,) to be inversely as the square roots of the distances from
the sun, it is evident, from what has been advanced, that an equilibrium
could still obtain, by variations in the densities, distances and
diameter of the planets. Supposing, again, that the planets still move
in the same plane, but in elliptical orbits, and that they are in
equilibrium at their mean distances, under the influence or action of
the tangential current, the radial stream, and the density of the ether;
we see that the force of the radial stream is too great at the
perihelion, and too small at the aphelion. At the perihelion the planet
is urged from the sun and at the aphelion towards the sun. The density
and consequent momentum is also relatively too great at the perihelion,
which also urges the planet from the sun, and at the aphelion,
relatively too small, which urges the planet towards sun; and the law is
the same in both cases, being null at the mean distance of the planet,
at a maximum at the apsides; it is, consequently, as the cosine of the
planet's eccentric anomaly at other distances, and is positive or
negative, according as the planet's distance is above or below the mean.
At the planet's mean distance, the circular velocity of the vortex is
equal to the circular velocity of the planet, and, at different
distances, is inversely in the sub-duplicate ratio of those distances.
But the circular velocity of a planet in the same orbit, is in the
simple ratio of the distances inversely. At the perihelion, the planet
therefore moves faster than the ether of the vortex, and at the
aphelion, slower; and the difference is as the square roots of the
distances; but the force of resistance is as the square of the velocity,
and is therefore in the simple ratio of the distances, as we have
already found for the effect of the radial stream, and centrifugal
momentum of the internal ether. At the perihelion this excess of
tangential velocity creates a resistance, which urges the planet towards
the sun, and at the aphelion, the deficiency of tangential velocity
urges the planet from the sun,--the maximum effect being at the apsides
of the orbit, and null at the mean distances. In other positions it is,
therefore, as the cosines of the eccentric anomaly, as in the former
case; but in this last case it is an addititious force at the
perihelion, and an ablatitious force at the aphelion, whereas the first
disturbing force was an ablatitious force at the perihelion, and an
addititious force at the aphelion; therefore, as we must suppose the
planet to be in equilibrium at its mean distance, it is in equilibrium
at all distances. Hence, a planet moving in the central plane of the
vortex, experiences no disturbance from the resistance of the ether.
As the eccentricities of the planetary orbits are continually changing
under the influence of the law of gravitation, we must inquire whether,
under these circumstances, such a change would not produce a permanent
derangement by a change in the mean force of the radial stream, so as to
increase or diminish the mean distance of the planet from the sun. The
law of force deduced from the theory for the radial stream is as the 2.5
power of the distances inversely. But, by dividing this ratio, we may
make the investigation easier; for it is equivalent to two forces, one
being as the squares of the distances, and another as the square roots
of the distances. For the former force, we find that in orbits having
the same major axis the mean effect will be as the minor axis of the
ellipse _inversely_, so that two planets moving in different orbits, but
at the same mean distance, experience a less or greater amount of
centripulsive force from this radial stream, according as their orbits
are of less or greater eccentricity, and this in the ratio of the minor
axis. On the other hand, under the influence of a force acting
centripulsively in the inverse ratio of the square roots of the
distances, we find the mean effect to be as the minor axis of the
ellipse _directly_, so that two planets in orbits of different
eccentricity, but having the same major axis, experience a different
amount from the action of this radial stream, the least eccentric orbit
being that which receives the greatest mean effect. By combining these
two results, we get a ratio of equality; and, consequently, the action
of the radial stream will be the same for the same orbit, whatever
change may take place in the eccentricity, and the mean distance of the
planet will be unchanged. A little consideration will also show that the
effect of the centrifugal momentum due to the density of ether will also
be the same by change of eccentricity; for the positive will always
balance the negative effect at the greatest and least distances of the
planet. The same remark applies to the effect of the tangential current,
so that no change can be produced in the major axes of the planetary
orbits by change of eccentricity, as an effect of the resistance of the
ether.
We will now suppose a planet's orbit to be inclined to the central plane
of the vortex, and in this case, also, we find, that the action of the
radial stream tends to increase the inclination in one quadrant as much
as it diminishes it in the next quadrant, so that no change of
inclination will result. But, if the inclination of the orbit be changed
by planetary perturbations, the mean effect of the radial stream will
also be changed, and this will tell on the major axis of the orbit,
enlarging the orbit when the inclination diminishes, and contracting it
when it increases. The change of inclination, however, must be referred
to the central plane of the vortex. Notwithstanding the perfection of
modern analysis, it is confessed that the recession of the moon's nodes
does yet differ from the theory by its 350th part, and a similar
discrepancy is found for the advance of the perigee.[40] This theory is
yet far too imperfect to say that the action of the ethereal medium will
account for these discrepancies; but it certainly wears a promising
aspect, worthy the notice of astronomers. There are other minute
discordancies between theory and observation in many astronomical
phenomena, which theory _is_ competent to remove. Some of these we shall
notice presently; and, it may be remarked, that it is in those minute
quantities which, in astronomy, are usually attributed to errors of
observation, that this theory will eventually find the surest evidence
of its truth.
KEPLER'S THIRD LAW ONLY APPROXIMATELY TRUE.
But it may be asked: If there be a modifying force in astronomy derived
from another source than that of gravitation, why is it that the
elements of the various members of the system derived solely from
gravitation should be so perfect? To this it may be answered, that
although astronomers have endeavored to derive every movement in the
heavens from that great principle, they have but partially succeeded.
Let us not surrender our right of examining Nature to the authority of a
great name, nor call any man master, either in moral or physical
science. It is well known that Kepler's law of the planetary distances
and periods, is a direct consequence of the Newtonian Law of
gravitation, and that the squares of the periodic times ought to be
proportional to the cubes of the mean distances. These times are given
accurately by the planets themselves, by the interval elapsing between
two consecutive passages of the node, and as in the case of the ancient
planets we have observations for more than two thousand years past,
these times are known to the fraction of the second. The determination
of the distances however, depends on the astronomer, and a tyro in the
science might suppose that these distances were actually measured; and
so they are roughly; but the astronomer does not depend on his
instruments, he trusts to _analogy_, and the mathematical perfection of
a law, which in the abstract is true; but which he does not know is
rigidly exact when applied to physical phenomena. From the immense
distance of the planets and the smallness of the earth, man is unable to
command a base line sufficiently long, to make the horizontal parallax a
sensible angle for the more distant planets; and there are difficulties
of no small magnitude to contend with, with those that are the nearest.
In the occasional transit of Venus across the sun, however, he is
presented with a means of measuring on an enlarged scale, from which the
distance of the sun is determined; and by _analogy_ the distance of all
the planets. Even the parallax of the sun itself is only correct, by
supposing that the square of the periodic time of Venus is in the same
proportion to the square of the periodic time of the earth as the cube
of her distance is to the cube of the earth's distance. Our next nearest
planet is Mars, and observations on this planet at its opposition to the
sun, invariably give a larger parallax for the sun--Venus giving 8.5776″
while Mars gives about 10″. It is true that the first is obtained under
more favorable circumstances; but this does not prove the last to be
incorrect. It is well known that the British Nautical Almanac contains a
list of stars lying in the path of the planet Mars about opposition,
(for the very purpose of obtaining a correct parallax,) that minute
differences of declination may be detected by simultaneous observations
in places having great differences of latitude. Yet strange to say, the
result is discredited when not conformable to the parallax given by
Venus. If then, we cannot trust the parallax of Mars, _à fortiori_, how
can we trust the parallax of Jupiter, and say that his mean distance
exactly corresponds to his periodic time? Let us suppose, for instance,
that the radius vector of Jupiter fell short of that indicated by
analogy by 10,000 miles, we say that it would be extremely difficult,
nay, utterly impossible, to detect it by instrumental means. Let not
astronomers, therefore, be too sure that there is not a modifying cause,
independent of gravitation, which they will yet have to recognize. The
moon's distance is about one-fourth of a million of miles, and Neptune's
2854 millions, or in the ratio of 10,000 to 1; yet even the moon's
parallax is not trusted in determining her mass, how then shall we
determine the parallax of Neptune? It is therefore _possible_ that the
effective action of the sun is in some small degree different, on the
different planets, whether due to the action of the ether, to the
similarity or dissimilarity of material elements, to the temperature of
the different bodies, or to all combined, is a question yet to be
considered.
As another evidence of the necessity of modifying the strict wording of
the Newtonian law, it is found that the disturbing action of Jupiter on
different bodies, gives different values for the mass of Jupiter. The
mass deduced from Jupiter's action on his satellites, is different from
that derived from the perturbations of Saturn, and this last does not
correspond with that given by Juno: Vesta also gives a different mass
from the comet of Encke, and both vary from the preceding values.[41]
In the analytical investigation of planetary disturbances, the
disturbing force is usually divided into a radial and tangential force;
the first changing the law of gravitation, to which law the elliptic
form of the orbit is due. The radial disturbing force, therefore, being
directed to or from the centre, can have no influence over the first law
of Kepler, which teaches that the radius vector of each planet having
the sun as the centre, describes equal areas in equal times. If the
radial disturbing force be exterior to the disturbed body, it will
diminish the central force, and cause a progressive motion in the
aphelion point of the orbit. In the case of the moon this motion is very
rapid, the apogee making an entire revolution in 3232 days. Does this,
however, correspond with the law of gravitation? Sir Isaac Newton, in
calculating the effect of the sun's disturbing force on the motion of
the moon's apogee, candidly concludes thus: "Idoque apsis summa singulis
revolutionibus progrediendo conficit 1° 31′ 28″. Apsis lunæ est duplo
velocior circiter." As there was a necessity for reconciling this
stubborn fact with the theory, his followers have made up the deficiency
by resorting to the tangential force, or, as Clairant proposed, by
continuing the approximations to terms of a higher order, or to the
square of the disturbing force.
Now, in a circular orbit, this tangential force will alternately
increase and diminish the velocity of the disturbed body, without
producing any permanent derangement, the same result would obtain in an
elliptical orbit, if the position of the major axis were stationary. In
the case of the moon, the apogee is caused to advance by the disturbing
power of the radial force, and, consequently, an exact compensation is
not effected: there remains a small excess of velocity which geometers
have considered equivalent to a doubling of the radial force, and have
thus obviated the difficulty. To those not imbued with the profound
penetration of the modern analyst, there must ever appear a little
inconsistency in this result. The major axis of a planet's orbit depends
solely on the velocity of the planet at a given distance from the sun,
and the tangential portion of the disturbance due to the sun, and
impressed upon the moon, must necessarily increase and diminish
alternately the velocity of the moon, and interfere with the equable
description of the areas. If, then, there be left outstanding a small
excess of velocity over and above the elliptical velocity of the moon,
at the end of each synodical revolution, in consequence of the motion
impressed on the moon's apogee by the radial force, the _legitimate_
effect would be a small enlargement of the lunar orbit every revolution
in a rapidly-increasing ratio, until the moon would at last be taken
entirely away. In the great inequality of Jupiter and Saturn, this
tangential force is not compensated at each revolution, in consequence
of continual changes in the configuration of the two planets at their
heliocentric conjunctions, with respect to the perihelion of their
orbits, and the near commensurability of their periods; and the effect
of the tangential force is, in this case, legitimately impressed on the
major axes of the orbits. But why (we may ask) should not this also be
expended on the motion of the aphelion as well as in the case of the
moon? Astronomy can make no distinctions between the orbit of a planet
and the orbit of a satellite. And, we might also ask, why the tangential
resistance to the comet of Encke should not also produce a retrograde
motion in the apsides of the orbit, instead of diminishing its period?
To the honor of Newton, be it remembered, that he never resorted to an
explanation of this phenomenon, which would vitiate that fundamental
proposition of his theory, in which the major axis of the orbit is shown
to depend on the velocity at any given distance from the focus.
Some cause, however, exists to double the motion of the apogee, and
that there is an outstanding excess of orbital velocity due to the
tangential force, is also true. This excess may tell in the way
proposed, provided some other arrangement exists to _prevent_ a
permanent dilation of the lunar orbit; and this provision may be found
in the increasing density of the ether, which prevents the moon
overstepping the bounds prescribed by her own density, and the force of
the radial stream of the terral vortex. In the case of Jupiter and
Saturn, their mutual action is much less interfered with by change of
density in the ether in the enlarged or contracted orbit, and,
consequently, the effect is natural. Thus, we have in the law of density
of the ethereal medium a better safeguard to the stability of the
dynamical balance of the system, than in the profound and beautiful
Theorems of La Grange. It will, of course, occur to every one, that we
are not to look for the same law in every vortex, and it will,
therefore, appear as if the satellites of Jupiter, whose theory is so
well known, should render apparent any deviation between their periodic
times and the periodic times of the contiguous parts of the vortex,
which would obtain, if the density of the ether in the Jovian vortex
were not as the square roots of the distances directly. But, we have
shown how there can be a balance preserved, if the tangential resistance
of the vortex shall be equal and contrary at the different distances at
which the satellites are placed; that is, if these two forces shall
follow the same law. These are matters, however, for future
investigation.
LIGHT AND HEAT.
But will not the admission of a vorticose motion of the ethereal medium,
affect the aberration of light? It is well known that the question has
been mooted, whether the velocity of reflected light is the same as that
of direct light. The value of aberration having been considered 20″.25,
from the eclipses of Jupiter's satellites, while later determinations,
from observations on Polaris, give 20″.45. It cannot be doubted that
light, in traversing the central parts of the solar vortex, that is,
having to cross the whole orbit of the earth, should pass this distance
in a portion of time somewhat different to a similar distance outside
the earth's orbit, where the density is greater, and consequently induce
an error in the aberration, determined by the eclipses of Jupiter's
satellites. In the case of Polaris, the circumstances are more equal;
still, a difference ought to be detected between the deduced aberration
in summer and in winter, as, in the first case, the light passes near
the axis of the solar vortex, where (according to the theory) a change
of density occurs. This is an important practical question, and the
suggestion is worthy attention. Now, the question occurs, will light
pass through the rarefied space with greater velocity than through the
denser ether beyond? From recent experiments, first instituted by Arago,
it is determined that light passes with less velocity through water than
through air; and one result of these experiments is the confirmation
they give to the theory of Fresnel, that the medium which conveys the
action of light partly partakes of the motion of the refracting body.
This of itself is a strong confirmation of this theory of an ethereal
medium. It may also be remarked, that every test applied to the
phenomenon of light, adds additional strength to the undulatory theory,
at the expense of the Newtonian theory of emission. As light occupies
time in traversing space, it must follow from the theory that it does
not come from the radiant point exactly in straight lines, inasmuch as
the ether itself is in motion tangentially,--the velocity being in the
sub-duplicate ratio of the distances from the sun inversely.
May not that singular phenomenon,--the projection of a star on the
moon's disc, at the time of an occultation,--be due to this curvature of
the path of a ray of light, by considering that the rays from the moon
have less intensity, but more mechanical momentum, and consequently
more power to keep a straight direction? Let us explain: we have urged
that light, as well as heat, is a mechanical effect of atomic motion,
propagated through an elastic medium; that, _ceteris paribus_, the
product of matter by its motion is ever a constant quantity for equal
spaces throughout the universe,--in a word, that it is, and must
necessarily be, a fundamental law of nature. All departures from this
law are consequences of accidental arrangements, which can only be
considered of temporary duration. Our knowledge of planetary matter
requires the admission of differences in the density, form, and size of
ultimate atoms, and, according to the above law, when the atoms are of
uniform temperature or motion, the product of the matter of each by its
motion, when reduced to the same space, will be constant. The momentum
of two different atoms, therefore, we will consider equal, for the sake
of illustration; yet this momentum is made up of two different
elements,--matter and motion. Let us exaggerate the difference, and
assign a ratio of 1000 to 1. Suppose a ball of iron of 1000 lbs.,
resting upon a horizontal plane, should be struck by another ball of 1
lb., having a motion of 1000 feet in a second, and, in a second case,
should be struck by a ball of 1000 lbs., having a velocity of 1 foot per
second, the momentum of each ball is similar; but experience proves that
the motion impressed on the ball at rest is not similar; the ponderous
weight and slow motion is far more effective in displacing this ball,
for the reason that time is essential to the distribution of the motion.
If the body to be struck be small as, for instance, a nail, a greater
motion and less matter is more effective than much matter and little
motion. Hence, we have a _distinction_ applicable to the difference of
momentum of luminous and calorific rays. The velocity of a wave of sound
through the atmosphere, is the same for the deep-toned thunder and the
shrillest whistle,--being dependent on the density of the medium, and
not on the source from which it emanates. So it is in the ethereal
medium.
This view is in accordance with the experiments of M. Delaroche and
Melloni, on the transmission of light and heat through diaphanous
bodies--the more calorific rays feeling more and more the influence of
thickness, showing that more motion was imparted to the particles of the
diaphanous substance by the rays possessing more material momentum, and
still more when the temperature of the radiating body was low, evidently
analogous to the illustration we have cited. Light may therefore be
regarded as the effect of the vibration of atoms having little mass, and
as this mass increases, the rays become more calorific, and finally the
calorific effect is the only evidence of their existence; as towards the
extreme red end of the spectrum they cease to be visible, owing to their
inability to impart their vibrations to the optic nerve. This may also
influence the law of gravitation. In this we have also an explanation of
the dispersion of light. The rays proceeding from atoms of small mass
having less material momentum, are the most refrangible, and those
possessing greater material momentum, are the least refrangible; so that
instead of presenting a difficulty in the undulatory theory of light,
this dispersion is a necessary consequence of its first principles.
It is inferred from the experiments cited, and the facts ascertained by
them, viz.: that the velocity of light in water is less than its
velocity in air; that the density of the ether is greater in the first
case; but this by no means follows. We have advocated the idea, that the
ethereal medium is less dense within a refracting body than without. We
regard it as a fundamental principle. Taking the free ether of heaven;
the vibrations in the denser ether will no doubt be slowest; but within
a refracting body we must consider there is motion lost, or _light
absorbed_, and the time of the transmission is thus increased.
There has been a phenomenon observed in transits of Mercury and Venus
across the sun, of which no explanation has been rendered by
astronomers. When these planets are visible on the solar disc, they are
seen surrounded by rings, as if the light was intercepted and increased
alternately. This is no doubt due to a small effect of interference,
caused by change of velocity in passing through the rarefied nucleus of
these planetary vortices, near the body of the planet, and through the
denser ether beyond, acting first as a concave, and secondly as a convex
refracting body; always considering that the ray will deviate _towards_
the side of least insistence, and thus interfere.
That heat is simply atomic motion, and altogether mechanical, is a
doctrine which ought never to have been questioned. The interest excited
by the bold experiments of Ericson, has caused the scientific to
_suspect_, that heat can be converted into motion, and motion into
heat--a fact which the author has considered too palpable to deny for
the last twenty years. He has ever regarded matter and motion as the two
great principles of nature, ever inseparable, yet variously combined;
and that without these two elements, we could have no conception of
anything existing.
It may be thought by some, who are afraid to follow truth up the rugged
precipices of the hill of knowledge, that this theory of an
interplanetary plenum leads to materialism; forgetting, that He who made
the world, formed it of matter, and pronounced it "very good." We may
consider ethereal matter, in one sense, _purer_ than planetary matter,
because unaffected by chemical laws. Whether still purer matter exists,
it is not for us to aver or deny. The Scriptures teach us that "there is
a natural body and there is a spiritual body." Beyond this we know
nothing. We, however, believe that the _invisible_ world of matter, can
only be comprehended by the indications of that which is visible; yet
while humbly endeavoring to connect by one common tie, the various
phenomena of matter and motion, we protest against those doctrines which
teach the eternal duration of the present order of things, as being
incompatible with the analogies of the past, as well as with the
revelations of the future.
FOOTNOTES:
[35] Silliman's Journal, vol xxxv., page 283.
[36] The real diameter of the earth in that latitude, whose sine is
one-third, is a little greater than this; but the true mean is more
favorable for the Newtonian law.
[37] This is, perhaps, the nearest ratio of the densities and distances.
[38] This is an important consideration, as bearing on the geology of
the earth.
[39] It is not as likely that the condensation of the sun was so sudden
as that of the planets, and therefore in this case this distance is only
approximate.
[40] Mechanique Celeste. Theory of the Moon.
[41] Mechanique Celeste. Masses of the planets.
SECTION FIFTH.
COMETARY PHENOMENA.
The planetary arrangements of the solar system are all _à priori_
indications of the theory of vortices, not only by the uniform direction
of the motions, the circular orbits in which these motions are
performed, the near coincidence of the planes of these orbits, and the
uniform direction of the rotation of the planets themselves; but, also,
by the law of densities and distances, which we have already attempted
to explain. In the motions of comets we find no such agreement. These
bodies move in planes at all possible inclinations in orbits extremely
eccentrical and without any general direction--as many moving contrary
to the direction of the planets as in the opposite direction; and when
we consider their great volume, and their want of mass, it appears, at
first sight, that comets do present a serious objection to the theory.
We shall point out, however, a number of _facts_ which tend to
invalidate this objection, and which will ultimately give the
preponderance to the opposite argument.
Every fact indicative of the nature of comets proves that the nuclei are
masses of material gases, similar, perhaps (at least in the case of the
short-period comets), to the elementary gases of our own planet, and,
consequently, these masses must be but small. In the nascent state of
the system, the radial stream of the vortex would operate as a fan,
purging the planetary materials of the least ponderable atoms, and, as
it were, separating the wheat from the chaff. It is thus we conceive
that the average atomic density of each planet has been first determined
by the radial stream, and, subsequently, that the solidification of the
nebulous planets has, by their atomic density, assigned to each its
position in the system, from the consequent relation which it
established between the density of the ether within the planet, and the
density of the ether external to it, so that, according to this view, a
single isolated atom of the same density as the mean atomic density of
the earth could (_ceteris paribus_) revolve in an orbit at the distance
of the earth, and in the same periodic time. This, however, is only
advanced by way of illustration.
The expulsive force of the radial stream would thus drive off this
cometary dust to distances in some inverse ratio of the density of the
atoms; but, a limit would ultimately be reached, when gravitation would
be relatively the strongest--the last force diminishing only as the
squares of the distances, and the first diminishing in the compound
ratio of the squares and the square roots of the distances. At the
extreme verge of the system, this cometary matter would accumulate, and,
by accumulation, would still further gather up the scattered atoms--the
sweepings of the inner space--and, in this condensed form, would again
visit the sun in an extremely elongated ellipse. It does not, however,
follow, that all comets are composed of such unsubstantial materials.
There may be comets moving in parabolas, or even in hyperbolas--bodies
which may have been accumulating for ages in the unknown regions of
space, far removed from the sun and stars, drifting on the mighty
currents of the great ethereal ocean, and thus brought within the sphere
of the sun's attraction; and these bodies may have no analogy to the
periodical comets of our system, which last are those with which we are
more immediately concerned.
The periodical comets known are clearly arranged into two distinct
classes--one having a mean distance between Saturn and Uranus, with a
period of about seventy-five years, and another class, whose mean
distance assigns their position between the smaller planets and Jupiter,
having periods of about six years. These last may be considered the
siftings of the smaller planets, and the first the refuse of the
Saturnian system. In this light we may look for comets having a mean
distance corresponding to the intervals of the planets, rather than to
the distances of the planets themselves. One remarkable fact, however,
to be observed in these bodies is, that all their motions are in the
same direction as the planets, and, with one exception, there is no
periodical comet positively known whose motion is retrograde.
The exception we have mentioned is the celebrated comet of Halley, whose
period is also about seventy-five years. In reasoning on the resistance
of the ether, we must consider that the case can have very little
analogy with the theory of projectiles in air; nor can we estimate the
inertia of an infinitely divisible fluid, from its resisting influence
on atomic matter, by a comparison of the resistance of an atomic fluid
on an atomic solid. Analogy will only justify comparisons of like with
like. The tangent of a comet's orbit, also, can only be tangential to
the circular motion of the ether at and near perihelion, which is a very
small portion of its period of revolution. As far as the tangential
resistance is concerned, therefore, it matters little whether its motion
be direct or retrograde. If a retrograde comet, of short period and
small eccentricity, were discovered moving also near the central plane
of the vortex, it would present a very serious objection, as being
indicative of contrary motions in the nascent state of the system. There
is no such case known. So, also, with the inclinations of the orbits; if
these be great, it matters little whether the comet moves in one way or
the other, as far as the tangential current of the vortex is concerned.
Yet, when we consider the average inclination of the orbit, and not of
its plane, we find that the major axes of nearly all known cometary
orbits are very little inclined to the plane of the ecliptic.
In the following table of all the periodical comets known, the
inclination of the major axis of the orbit is calculated to the nearest
degree; but all cometary orbits with very few exceptions, will be found
to respect the ecliptic, and never to deviate far from that plane:
+--------------------------------------------------------------------+
| Designations | Periodic | Inclination | Motion | Planetary |
| of the Comets. | times. | of | in Orbit. | Intervals. |
| | | Major Axes | | |
|--------------------------------------------------------------------|
|Encke | 1818 | 3 years. | 1° | Direct |Mars & Ceres.|
|--------------------------------------------------------------------|
|De Vico | 1814 | | 2 | Direct | |
|Fayo | 1843 | | 4 | Direct | Ceres |
|De Avrest| 1851 | From | 1 | Direct | |
|Brorsen | 1846 | five | 7 | Direct | and |
|Messier | 1766 | to | 0 | Direct | |
|Clausen | 1743 | six | 0 | Direct | Jupiter. |
|Pigott | 1783 | or | 4 | Direct | |
|Pous | 1819 | seven | 3 | Direct | |
|Biela | 1826 | years. | 9 | Direct | |
|Blaupain | 1819 | | 2 | Direct | |
|Lexell | 1770 | | 1 | Direct | |
|--------------------------------------------------------------------|
|Pous | 1812 | | 17 | Direct | |
|Olbers | 1816 | about | 40 | Direct | Saturn |
|De Vico | 1846 | 75 | 13 | Direct | and |
|Brorsen | 1847 | years. | 12 | Direct | Uranus. |
|Westphal | 1852 | | 21 | Direct | |
|Halley | 1682 | | 16 | Retrograde| |
+--------------------------------------------------------------------+
From which it appears, that the objection arising from the great
inclination of the _planes_ of these orbits is much less important than
at first it appears to be.
Regarding then, that a comet's mean distance depends on its mean atomic
density, as in the case of the planets, the undue enlargement of their
orbits by planetary perturbations is inadmissible. In 1770 Messier
discovered a comet which approached nearer the earth than any comet
known, and it was found to move in a small ellipse with a period of five
and a half years; but although repeatedly sought for, it was the
opinion of many, that it has never been since seen. The cause of this
seeming anomaly is found by astronomers in the disturbing power of
Jupiter,--near which planet the comet must have passed in 1779, but the
comet was not seen in 1776 before it passed near Jupiter, although a
very close search was kept up about this time. Now there are two
suppositions in reference to this body: the comet either moved in a
larger orbit previous to 1767, and was then caused by Jupiter to
diminish its velocity sufficiently to give it a period of five and a
half years, and that after perihelion it recovered a portion of its
velocity in endeavoring to get back into its natural orbit; or if moving
in the natural orbit in 1770, and by passing near Jupiter in 1779 this
orbit was deranged, the comet will ultimately return to that mean
distance although not necessarily having elements even approximating
those of 1770. In 1844, September 15th, the author discovered a comet in
the constellation Cetus, (the same previously discovered by De Vico at
Home,) and from positions _estimated with the naked eye_ approximately
determined the form of its orbit and its periodic time to be very
similar to the lost comet of 1770. These conclusions were published in a
western paper in October 1844, on which occasion he expressed the
conviction, that this was no other than the comet of 1770. As the
question bore strongly on his theory he paid the greater attention to
it, and had, previously to this time, often searched in hopes of finding
that very comet. Since then, M. Le Verrier has examined the question of
identity and given his decision against it; but the author is still
sanguine that the comet of 1844 is the same as that of 1770, once more
settled at its natural distance from the sun. This comet returns to its
perihelion on the 6th of August, 1855, according to Dr. Brünnow, when,
it is hoped, the question of identity will be reconsidered with
reference to the author's principles; and, that when astronomers become
satisfied of this, they will do him the justice of acknowledging that
he was the first who gave publicity to the fact, that the "Lost Comet"
was found.
That comets do experience a resistance, is undeniable; but not in the
way astronomers suppose, if these views be correct. The investigations
of Professor Encke, of Berlin, on the comet which bears his name, has
determined the necessity of a correction, which has been applied for
several returns with apparent success. But there is this peculiarity
about it, which adds strength to our theory: "The Constant of
Resistance" requires a change after perihelion. The necessity for this
change shows the action of the radial stream. From the law of this
force, (reckoning on the central plane of the vortex,) there is an
outstanding portion, acting as a disturbing power, in the sub-duplicate
ratio of the distances inversely. If we only consider the mean or
average effect in orbits nearly circular, this force may be considered
as an ablatitious force at all distances below the mean, counterbalanced
by an opposite effect at all distances above the mean. But when the
orbits become very eccentrical, we must consider this force as
momentarily affecting a comet's velocity, diminishing it as it
approaches the perihelion, and increasing it when leaving the
perihelion. A resolution of this force is also requisite for the comet's
distance above the central plane of the vortex, and a correction,
likewise, for the intensity of the force estimated in that plane. There
is also a correction necessary for the perihelion distance, and another
for the tangential current; but we are only considering here the general
effect. By diminishing the comet's proper velocity in its orbit, if we
consider the attraction of the sun to remain the same, the general
effect _may_ be (for this depends on the tangential portion of the
resolved force preponderating) that the absolute velocity will be
increased, and the periodic time shortened; but after passing the
perihelion, with the velocity of a smaller orbit, there is also
superadded to this already undue velocity, the expulsive power of the
radial stream, adding additional velocity to the comet; the orbit is
therefore enlarged, and the periodic time increased. Hence the necessity
of changing the "Constant of Resistance" after perihelion, and this will
generally be found necessary in all cometary orbits, if this theory be
true. But this question is one which may be emphatically called the most
difficult of dynamical problems, and it may be long before it is fully
understood.
According to the calculations of Professor Encke, the comet's period is
accelerated about 2 hours, 30 minutes, at each return, which he
considers due to a resisting medium. May it not rather be owing to _the
change of inclination of the major axis of the orbit, to the central
plane of the vortex_? Suppose the inclination of the _plane_ of the
orbit to remain unchanged, and the eccentricity of the orbit also, if
the longitude of the perihelion coincides with that of either node, the
major axis of the orbit lies in the ecliptic, and the comet then
experiences the greatest mean effect from the radial stream; its mean
distance is then, _ceteris paribus_, the greatest. When the angle
between the perihelion and the nearest node increases, the mean force of
the radial stream is diminished, and the mean distance is diminished
also. When the angle is 90°, the effect is least, and the mean distance
least. This is supposing the ecliptic the central plane of the vortex.
When Encke's formula was applied to Biela's comet, it was inadequate to
account for a tenth part of the acceleration; and although Biela moves
in a much denser medium, and is of less dense materials, even this taken
into account will not satisfy the observations,--making no other change
in Encke's formula. We must therefore attribute it to changes in the
elements of the orbits of these comets. Now, the effect of resistance
should also have been noticed, as an acceleration of Halley's comet in
1835, yet the period was prolonged. To show, that our theory of the
_cause_ of these anomalies corresponds with facts, we subjoin the
elements in the following tables, taken from Mr. Hind's catalogue:
THE ELEMENTS OF ENCKE'S COMET.
Date of Longitude of Longitude of Difference of
Perihelion. Perihelion. nearest Node Longitude.
1822 157° 11′ 44″ 154° 25′ 9″ 2° 46′ 35″
1825 157 14 31 154 27 30 2 47 1
1829 157 17 53 154 29 32 2 48 21
1832[42] 157 21 1 154 32 9 2 41 52
1835 157 23 29 154 34 59 2 48 30
1838 157 27 4 154 36 41 2 50 23
1842 157 29 27 154 39 10 2 50 17
1845 157 44 21 154 19 33 3 24 48
1848 157 47 8 154 22 12 3 24 56
1852 157 51 2 154 23 21 3 27 41
In this we see a regular increase of the angle, which ought to be
attended with a small acceleration of the comet; but the change of
inclination of the orbit ought also to be taken into consideration, to
get the mean distance of the comet above the plane of the vortex, and,
by this, the mean force of the radial stream.
In the following table, the same comparison is made for Biela's comet:--
ELEMENTS OF BIELA'S COMET.
Date of Longitude of Longitude of Difference of
Perihelion. Perihelion. nearest Node. Longitude.
1772 110° 14′ 54″ 74° 0′ 1″ 36° 14′ 53″
1806 109 32 23 71 15 15 38 17 8
1826 109 45 50 71 28 12 38 17 38[43]
1832 110 55 55 68 15 36 41 45 19
1846 109 2 20 65 54 39 43 7 41
Between 1832 and 1846, the increase of the angle is twice as great for
Biela as for Encke, and the angle itself throws the major axis of Biela
10° above the ecliptic, whereas the angle made by Encke's major axis, is
only about 1°; the cosine of the first angle, diminishes much faster
therefore, and consequently the same difference of longitude between the
perihelion and node, will cause a greater acceleration of Biela; and
according to Prof. Encke's theory, Biela would require a resisting
medium twenty-five times greater than the comet of Encke to reconcile
observation with the theory. Halley's comet can scarcely be considered
to have had an orbit with perfect elements before 1835. If they were
known accurately for 1759, we should no doubt find, that the angle
between the node and perihelion _diminished_ in the interval between
1750 and 1835, as according to the calculations of M. Rosenberg, the
comet was six days behind its time--a fact fatal to the common ideas of
a resisting medium; but this amount of error must be received as only
approximate.
No comet that has revisited the sun, has given astronomers more trouble
than the great comet of 1843. Various orbits have been tried,
elliptical, parabolic and hyperbolic; yet none will accord with all the
observations. The day before this comet was seen in Europe and the
United States, it was seen close to the body of the sun at Conception,
in South America; yet this observation, combined with those following,
would give an orbital velocity due to a very moderate mean distance.
Subsequent observations best accorded with a hyperbolic orbit; and it
was in view of this anomaly, that the late Sears C. Walker considered
that the comet came into collision with the sun in an elliptical orbit,
and its _debris_ passed off again in a hyperbola. That a concussion
would not add to its velocity is certain, and the departure in a
hyperbolic orbit would be contrary to the law of gravitation. This
principle is thus stated by Newton:--"In parabola velocitas ubiquo
equalis est velocitati corporis revolventis in circulo ad dimidiam
distantiam; in ellipsi minor est in hyperbola major." (Vid. Prin. Lib.
1. Prop. 6 Cor. 7.)
But as regards the _fact_, it is probable that Mr. Walker's views are
correct, so far as the change from an ellipse to an hyperbola is
considered. The Conception observation cannot be summarily set aside,
and Professor Peirce acknowledges, that "If it was made with anything of
the accuracy which might be expected from Captain Ray, it exhibits a
decided anomaly in the nature of the forces to which the comet was
subjected during its perihelion passage." The comet came up to the sun
almost in a straight line against the full force of the radial stream;
its velocity must therefore necessarily have been diminished. After its
perihelion, its path was directly _from_ the sun, and an undue velocity
would be kept up by the auxiliary force impressed upon it by the same
radial stream; and hence, the later observations give orbits much larger
than the early ones, and there can be no chance of identifying this
comet with any of its former appearances, even should its orbit be
elliptical. This unexpected confirmation of the theory by the
observation of Capt. Ray, cannot easily be surmounted.
We must now endeavor to explain the physical peculiarities of comets, in
accordance with the principles laid down. The most prominent phenomenon
of this class is the change of diameter of the visible nebulosity. It is
a most singular circumstance, but well established as a fact, that a
comet contracts in its dimensions on approaching the sun, and expands on
leaving it. In 1829, accurate measures were taken on different days, of
the diameter of Encke's comet, and again in 1838. The comet of 1618 was
also observed by Kepler with this very object, and also the comet of
1807; but without multiplying instances, it may be asserted that it is
one of those facts in cometary phenomena, to which there are no
exceptions. According to all analogy, the very reverse of this ought to
obtain. If a comet is chiefly vaporous, (as this change of volume would
seem to indicate,) its approach to the sun ought to be attended by a
corresponding expansion by increase of temperature. When the contrary is
observed, and invariably so, it ought to be regarded as an index of the
existence of other forces besides gravitation, increasing rapidly in the
neighborhood of the sun; for the disturbing power of the sun's
attraction would be to enlarge the diameter of a comet in proportion to
its proximity. Now, the force of the radial stream, as we have shown, is
as the 2.5th power of the distances inversely. If this alternate
contraction and expansion be due to the action of this force, there
ought to be an approximate correspondence of the law of the effect with
the law of the cause. Arago, in speaking of the comet of 1829, states,
"that between the 28th of October and the 24th of December, the volume
of the comet was reduced as 16000 to 1, the change of distance in the
meantime only varying about 3 to 1." To account for this, a memoir was
published on the subject by M. Valz, in which he supposes an atmosphere
around the sun, whose condensation increases rapidly from superincumbent
pressure; so that the deeper the comet penetrates into this atmosphere
the greater will be the pressure, and the less the volume. In this it is
evident, that the ponderous nature of a resisting medium is not yet
banished from the schools. In commenting on this memoir, Arago justly
observes, that "there would be no difficulty in this if it could be
admitted that the exterior envelope of the nebulosity were not permeable
to the ether; but this difficulty seems insurmountable, and merits our
sincere regret; for M. Valz's ingenious hypothesis has laid down the law
of variation of the bulk of the nebulosity, as well for the short-period
comet as for that of 1618, with a truly wonderful exactness." Now, if we
make the calculation, we shall find that the diameter of the nebulosity
of a comet is inversely as the force of the radial stream. This force is
inversely as the 2.5 power of the distances from the axis, and not from
the sun: it will, therefore, be in the inverse ratio of the cosine of
the comet's heliocentric latitude to radius, and to this ratio the
comet's distance ought to be reduced. But, this will only be correct for
the same plane or for equal distances above the ecliptic plane,
considering this last as approximately the central plane of the vortex.
From the principles already advanced, the radial stream is far more
powerful on the central plane than in more remote planes; therefore, if
a comet, by increase of latitude, approaches near the axis, thus
receiving a larger amount of force from the radial stream in that plane
than pertains to its actual distance from the sun, it will also receive
a less amount of force in that plane than it would in the central plane
at the same distance from the axis. Now, we do not know the difference
of force at different elevations above the central plane of the vortex;
but as the two differences due to elevation are contrary in their
effects and tend to neutralize each other, we shall make the calculation
as if the distances were truly reckoned from the centre of the sun.
The following table is extracted from Arago's tract on Comets, and
represents the variations of the diameter of Encke's comet at different
distances from the sun,--the radius of the orbis magnus being taken as
unity.
Times of observation, Distances of the Real diameters
1828. comet from the sun. in radii of the earth.
Oct. 28 1.4617 79.4
Nov. 7 1.3217 64.8
Nov. 30 0.9668 29.8
Dec. 7 0.8473 19.9
Dec. 14 0.7285 11.3
Dec. 24 0.6419 3.1
In order the better to compare the diameters with the force, we will
reduce them by making the first numbers equal.
Distances. Diameters. The 2.5th power Reduced
of the Distances. Diameters.
1.4617 79.4 2.58 2.58
1.3217 64.8 2.10 2.10
0.9668 29.8 0.92 0.97
0.8473 19.9 0.66 0.65
0.7285 11.3 0.45 0.37
0.5419 3.1 0.21 0.10
This is a very close approximation, when we consider the difficulty of
micrometric measurement, and the fact, that as the comet gets nearer to
the sun, as at the last date of the table, the diameter is more than
proportionally diminished by the fainter nebulosity becoming invisible.
But, there may be a reality in the discrepancy apparent at the last
date, as the comet was then very near the plane of the ecliptic, and
was, consequently, exposed to the more violent action of the radial
stream.
To attempt to explain the _modus agendi_ is, perhaps, premature. Our
principal aim is to pioneer the way into the labyrinth, and it is
sufficient to connect this seeming anomaly with the same general law we
have deduced from other phenomena. Still, an explanation may be given in
strict accordance with the general principles of the theory.
Admitting the _nucleus_ of a comet to be gaseous, there is no difficulty
about the solution. According to Sir John Herschel, "stars of the
smallest magnitude remain distinctly visible, though covered by what
appears the densest portion of their substances; and since it is an
observed fact, that the large comets which have presented the appearance
of a nucleus, have yet exhibited no phases, though we cannot doubt that
they shine by the reflected solar light, it follows that even these can
only be regarded as great masses of thin vapor." That comets shine
solely by reflected solar light, is a position that we shall presently
question; but that they are masses of vapor is too evident to dispute.
According to the same authority quoted above, "If the earth were reduced
to the one thousandth part of its actual mass, its coercive power over
the atmosphere would be diminished in the same proportion, and in
consequence the latter would expand to a thousand times its actual
_bulk_." If this were so, and comets composed of the elementary gases,
some of them would have very respectable masses, as the nuclei are
frequently not more than 5,000 miles in diameter, and consequently it
becomes important to examine the principle. From all experiments the
density of an elastic fluid is directly as the compressing force; and if
a cylinder reached to the top of our atmosphere, compressed by the
gravitation of the earth, considered equal at each end of the cylinder,
it would represent the actual compressing force to which it owes its
density. If the gravitation of the earth were diminished one thousand
times this atmospheric column would expand one thousand times,[44]
(taking no account of the decrease of gravitation by increase of
distance;) so that the diameter of the aërial globe would be increased
to 108,000 miles, taking the atmosphere at 50 miles. But the mere
increasing the _bulk_ of the atmosphere 1000 times would increase the
diameter to little more than double. Even giving the correct expansion,
a comet's mass must be much greater than is generally supposed, or the
diameters of the nuclei would be greater if composed of any gas lighter
than atmospheric air.
It is very improbable that a comet is composed of only one elementary
gas, and if of many, their specific gravities will vary; the lighter, of
course, occupying the exterior layers. With such a small mass,
therefore, the upper portion of its atmosphere must be very attenuated.
Now let us remember that the density of the ether at a comet's aphelion,
is greater than at the perihelion, in the direct ratio of the square
roots of the distances from the sun nearly. At the aphelion the comet
lingers through half his period, giving ample time for the nucleus to be
permeated by ether proportionally dense with the surrounding ether of
the vortex at that distance. Thus situated, the comet descends to its
perihelion, getting faster and faster into a medium far less dense, and
there must consequently be an escape from the nucleus, or in common
parlance, the comet is positively electric. This escaping ether, in
passing through the attenuated layers composing the surface of the
nucleus, impels the lighter atoms of cometic dust further from the
centre, and as for as this _doubly_ attenuated atmosphere of isolated
particles extends, so far will the escaping ether be rendered luminous.
It may be objected here, that a contrary effect ought to be produced
when the comet is forsaking, its perihelion; but the objection is
premature, as the heat received from the sun will have the same effect
in increasing the elasticity, as change of density, and the comet will
probably part with its internal ether as long as it is visible to the
earth; and not fully regain it perhaps, until after it arrives at its
aphelion. Suppose that we admit that a comet continues to expand in the
same ratio for all distances, as is laid down for the comet of Encke
when near its perihelion; it would follow, that the comet of 1811, would
have a diameter at its aphelion of fifty millions of millions of miles,
that is, its outside would extend one thousand times further from the
sun, at the opposite side to that occupied by the centre of the comet,
than the distance of the comet's centre from the sun, at its enormous
aphelion distance. Such an absurdity shows us that there is a limit of
expansion due to natural causes, and that if there were no radial stream
the volume of a comet would be greatest when nearest the sun.
But while the comet is shortening its distance and hastening to the sun
in the form of a huge globular mass of diffuse light, it is continually
encountering another force, increasing in a far more rapid ratio than
the law of gravitation. At great distances from the sun, the force of
the radial stream was insufficient to detach any portion of the comet's
atmosphere; presently, however, the globular form is changed to an
ellipsoid, the radial stream begins to strip the comet of that doubly
attenuated atmosphere of which we have spoken, and the diameter of the
comet is diminished, merely because the luminosity of the escaping ether
is terminated at the limit of that atmosphere. Meanwhile the mass of the
comet has suffered only an infinitely small diminution; but if the
perihelion distance be small, the force may become powerful enough to
detach the heavier particles of the nucleus, and thus a comet may suffer
in mass by this denudating process. We regard, therefore, the nucleus of
a comet to represent the mass of the comet and the coma, as auroral rays
passing through a very attenuated envelope of detached particles. The
individual gravitating force of these particles to the comet's centre,
may be therefore considered as inversely as the squares of the
distances, and directly as the density of the particles; and this
density will, according to analogical reasoning, be as the distances or
square roots of the distances;--grant the last ratio, and the
gravitating force of the particles composing the exterior envelope of a
comet, becomes inversely as the 2.5th power of the distances from the
comet's centre.[45] This being the law of the radial stream, it follows,
of course, that a comet's diameter is inversely as the force of the
radial stream. It must, however, be borne in mind, that we are speaking
of the atomic density, and not of density by compression; for this
cometary dust, which renders luminous the escaping ether of the nucleus,
must be far too much diffused to merit the name of an elastic fluid. May
not the concentric rings, which were so conspicuous in the comet of
1811, be owing to differences in the gravitating forces of such
particles, sifted, as it were, and thus arranged, according to some
ratio of the distances, by the centripulsive force of the electric coma,
leaving vacant intervals, through which the ether passed without
becoming luminous? This at least is the explanation given by our theory.
We may, indeed, consider it possible that the escaping ether, when very
intense, might be rendered luminous by passing into the surrounding
ether, and, as it became more diffused by radiation, at last become
invisible. In this case, as the law of radiation is as the squares of
the distances from the centre inversely, the rays would be more and more
bent at right angles, or apparently shortened, as the power of the
radial stream increased, and the apparent diameters of the coma would
be diminished faster than the ratio of the 2.5th power of the distances.
But whichever view we adopt, the diameter would again increase in the
same ratio on leaving the sun, if we make allowance for increase of
temperature, as well as for diminution of density, for the ordinary
distance of a comet's visibility. We, however, regard the change of
diameter, as due to both these nodes of action, as best agreeing with
the indications afforded by their tails.
From the preceding remarks, it results that the density of the particles
producing the nebulous envelope of a comet, renders the variations of
diameter only approximate to the law of the radial stream; a comet's own
electric energy, or the intensity of the escaping ether, may also modify
this expression, and many other causes may be suggested. That the radial
stream is the cause, in the way we have pointed out, is proved by the
positions of the major axis of the short-period comet, making frequently
nearly a right angle with the radius vector of the orbit in 1828. A soap
bubble gently blown aside, without detaching it from the pipe, will
afford a good illustration of the mode, and a confirmation of the cause.
The angles measured by Struve, reckoned from the radius vector,
prolonged towards the sun, are subjoined:
November 7 99°.7 | December 7 154°.0
November 30 145 .3 | December 14 149 .4
At this last date, the comet was getting pretty close to the sun. When
the angle was greater, as on November 7th, the comet appeared to make
almost a right angle with the radius vector; and in this position of the
earth and comet, the longer axis of the elliptical comet was directed to
the axis of the vortex, as may be verified by experiment. At the later
dates, the comet was more rapidly descending, and, at the same time, the
axis of the comet was getting more directed towards the earth; so that
the angle increased between this axis and the radius vector, and
consequently became more coincident with it. We have now to consider the
luminous appendage of a comet, commonly called a tail.
The various theories hitherto proposed to account for this appendage are
liable to grave objections. That it is not refracted light needs not a
word of comment. Newton supposes the tail to partake of the nature of
vapor, rising from the sun by its extreme levity, as smoke in a chimney,
and rendered visible by the reflected light of the sun. But, how vapor
should rise towards opposition in a vacuum, is utterly inexplicable. In
speaking of the greater number of comets near the sun than on the
opposite side, he observes: "Hinc etiam manifestum est quod cœli
resistentiâ destituuntur."[46] And again, in another place, speaking of
the tail moving with the same velocity of the comet, he says: "Et hinc
rursus colligitur spatia cœlestia vi resistendi destitui; utpote in
quibus non solum solida planetarum et cometarum corpora, sed etiam
rarissimi candarum vapores motus suos velocissimos liberrimè peragunt ac
diutissimè conservant." On what _principle_, therefore, Newton relied to
cause the vapors to ascend, does not appear. Hydrogen rises in our
atmosphere because specifically lighter. If there were no atmosphere,
hydrogen would not rise, but merely expand on all sides. But, a comet's
tail shoots off into space in a straight line of one hundred millions of
miles, and frequently as much as ten millions of miles in a single day,
as in the case of the comet of 1843. Sir John Herschel observes, that
"no rational or even plausible account has yet been rendered of those
immensely luminous appendages which they bear about with them, and which
are known as their tails." Yet, he believes, and astronomers generally
believe, that a comet shines by reflected light. This theory of
reflexion is the incubus which clogs the question with such formidable
difficulties; for, it follows, that the reflecting matter must come
from the comet. But, what wonderful elements must a comet be made of, to
project themselves into space with such immense velocity, and in such
enormous quantities as to exceed in volume the body from which they
emanate many millions of times. This theory may be, therefore, safely
rejected.
From what we have already advanced concerning the coma or nebulosity of
the comet, we pass by an easy path to an explanation of the tail. In the
short-period comets, the density of the elementary atoms is too great to
be detached in the gross from the nucleus, or, rather, the density of
the atoms composing the nucleus is too great to permit the radiating
stream of the comet carrying them to a sufficient distance to be
detached by the radial stream of the sun. Hence, these comets exhibit
but very little tails. We may also conceive, that the continual siftings
which the nucleus undergoes at each successive perihelion passage, have
left but little of those lighter elements in comets whose mean distances
are so small. Yet, again, if by any chance the eccentricity is
increased, there are two causes--the density of the ether, and the heat
of the sun--which may make a comet assume quite an imposing appearance
when apparently reduced to the comparatively passive state above
mentioned.
According to our theory, then, the coma of a comet is due to the
elasticity of the ethereal medium within the nucleus, caused both by the
diminished pressure of the external ether near the sun, and also by the
increased temperature acting on the nucleus, and thus on the involved
ether. The tail, on the contrary, is caused by the lighter particles of
the comet's attenuated atmosphere being blown off by the electric blast
of the radial stream of the solar vortex, in sufficient quantities to
render its passage visible. It is not, therefore, reflected light, but
an ethereal stream rendered luminous by this detached matter still held
in check by the gravitating force of the sun, whose centre each
particle still respects, and endeavors to describe such an orbit as
results from its own atomic density, and the resultant action of both
the acting forces. From the law of density of the ether, the coma ought
to be brightest and the radiating stream of the comet's nucleus
strongest on the side of least pressure: from this cause, and the fact
that the body of the comet affords a certain protection to the particles
immediately behind it, there will be an interval between the comet and
the tail less luminous, as is almost invariably observed. We thus have
an explanation of the fact noticed by Sir John Herschel, "that the
structure of a comet, as seen in section in the direction of its length,
must be that of a hollow envelope of a parabolic form, enclosing near
its vertex the nucleus or head." We have, also, a satisfactory
explanation of the rapid formation of the tail; of its being wider and
fainter at its extremity; of its occasional curvature; and of its
greater length after perihelion than before. But, more especially may we
point to the explanation which this theory gives of the fact, that,
_ceteris paribus_, the long-period comets, when their perihelion
distances are small, have tails of such exaggerated dimensions.
A comet, whose mean distance is considerable, is supposed by the theory
to be composed of elements less dense, and, during its long sojourn at
its aphelion, it may be also supposed that it there receives continual
accessions to its volume from the diffused siftings of the system, and
from the scattered debris of other comets. On approaching the
perihelion, the rapidity of the change in the density of the ether in a
given time, depends on the eccentricity of the orbit, and so does the
change of temperature; so that, from both causes, both the length of the
tail and the brilliancy of the comet measurably depends on the magnitude
of the period and of the eccentricity.
If the nuclei of comets be gaseous as we suppose, and that the smallest
stars are visible through them, it is an outrage on common sense, to
refer that light, which renders a comet visible at noon-day, within six
minutes of space of the sun itself, to the reflected light of the sun.
When a small star has been seen through the nucleus of a comet, without
any perceptible diminution of light, it indicates perfect transparency;
but there can be no reflection from a perfectly transparent body, and
therefore, a comet does not shine by reflected light. It is true that
Arago discovered traces of polarized light in the comet of 1819, and
also in more recent comets, but they are mere traces, and Arago himself
admits, that they do not permit "the conclusion decidedly that these
stars shine only with a borrowed light." But it still does not follow
that a comet (even if independent of reflected light) is in an
incandescent state. The auroral light is not polarized, nor any other
electric light, neither is it owing to a state of incandescence, yet it
is luminous. The intense light of a comet at perihelion is analogous to
the charcoal points of a galvanic battery, caused by a rapid current of
ether from the nucleus, and assisted by the radial stream of the vortex.
This will account for the phenomenon in all its shades of intensity, as
well as for the absence of any perceptible phase. It will also account
for the non-combustion of such comets as those of the years 1680 and
1843. We shall also be at no loss to understand, why there is no
refraction when a ray of light from a star passes through the nebulosity
of a comet; and if, as we may reasonably suppose, the gaseous matter
composing the nucleus be very attenuated, instruments are yet too
imperfect to determine whether these also have any refracting power. On
this point, however, it is safest to suspend our judgment, as there may
be comets not belonging to our system, with even liquid or solid nuclei,
or of matter widely different to those elements composing the members of
the solar system.
In addition to what has been already advanced on this subject of a
comet's light, we may appeal to the well-known fact that the visibility
of a comet is not reciprocally as the squares of the distances from the
earth and sun as it ought to be, if shining by reflected light. In
Mr. Hind's late work on comets, the fact is stated that "Dr. Olbers
found that the comet of 1780 attained its greatest brightness on the 8th
of November, thirteen days subsequent to its discovery, whereas
according to the law of reflected light, it should have become gradually
fainter from the day of its discovery; and supposing the comet
self-luminous, the intensity of light should have increased each day
until November 26th; yet in the interval between the 8th and 26th of
that month, it grew rapidly less." Now this theory teaches, that a comet
is neither self-luminous nor dependent on the sun, but on its distance
from the axis of the vortex, and a certain amount of elapsed time from
the perihelion, varying somewhat in each particular case. This fact is
therefore a very strong argument in favor of our theory.
Amidst the many anomalous peculiarities of comets, it has been noticed
that a short tail is sometimes seen at right angles to the principal
tail, and in a few cases pointing directly towards the sun. Much of this
may be owing to perspective, but granting the reality of the fact, it is
still explicable on the same general principles.
In speaking of the modifying causes which influence the weather, we
mentioned the effect due to the position of the sun with respect to the
axis of the vortex. This will be found to have a sensible effect on the
action of the radial stream. The natural direction of a comet's electric
stream is _towards_ the axis of the vortex, and in the central plane of
the vortex it will be also towards the sun. But this stream is met by
the stronger radial stream from the axis, and as Mr. Hind describes it,
"is driven _backward_ in two streams passing on either side of the head,
and ultimately blending into one to form the tail." Now, if the body of
the sun be situated between the comet and the axis of the vortex, it
will shield the comet from the action of the radial stream, and thus a
tail may really point towards the sun.
In 1744 a brilliant comet exhibited six distinct tails spread out like a
fan, some seven days after its perihelion passage; its distance from
the sun at the time not being more than a third of the earth's distance.
The comet was then rapidly approaching the plane of the ecliptic, and if
we make the calculation for the position of the sun, we shall find that
the body of the sun was on the same side of the axis of the vortex as
the comet, and that the comet was then situated at the boundaries of the
conical space, enclosed by the radial stream in its deflected passage
round the body of the sun. In this position there are numerous cross
currents of the stream, and hence the phenomenon in question. As this
fact rests on the testimony of one individual, and is an occurrence
never recorded before or since, many are disposed to doubt the fact, yet
our theory explains even this peculiarity, and shows that there is no
necessity for impugning the statement of Cheseaux.
Another unexplained phenomenon is the corruscation of the tail. It has
been attempted to explode this fact also, by referring it to conditions
of our own atmosphere; and it is generally considered the argument of
Olbers, founded on the great length of the tail and the velocity of
light, is sufficient to prove that these corruscations are not actually
in the tail. Now, it is undoubtedly true, that as light travels less
than two hundred thousand miles in a second, and a comet's tail is
frequently one hundred millions long, it is impossible to see an
instantaneous motion along the whole line of the tail; but granting that
there are such flickerings in the tail as are described by so many, it
must necessarily be, that these flickerings will be _visible_. It would
be wonderful indeed, if a series of waves passing from the comet to the
extremity of the tail, should have their phases so exactly harmonizing
with their respective distances as to produce a uniform steady light
from a light in rapid motion. The argument, therefore, proves too much,
and as it is in the very nature of electric light thus to corruscate, as
we see frequently in the northern lights, we must be permitted still to
believe that not only the tails, but also the heads of comets do really
corruscate as described.
With respect to the direction of the tail, astronomers have been forced
to abandon the antiquated notion, that the tail always pointed directly
from the sun; yet they still pertinaciously cling to the idea, that
although this is not always the case, the tail only deviates from this
direction _in the plane of the orbit_. As this is a most important
question, it is necessary formally to protest against such a conclusion.
If the earth should happen to be in the plane of the comet's orbit and
the tail appears in that plane, it must of course be in that plane
_really_; but if the earth is not in the plane of the comet's orbit, the
tail is not _necessarily_ in the same plane, whatever its apparent
direction may indicate. It is true there is a tendency of every particle
of the tail, moving under the restraining influence of the sun's
attraction, to continue in the plane of the orbit; and in certain
positions there is no oblique action arising from the force of the
radial stream to cause it to deviate from that plane; yet in other
positions of the comet, the action of the radial stream may be oblique,
forcing it out of that plane, and still such a direction might be
assigned to it as to make it conform. In the comet of 1843, P. Smythe
observed a forked tail 25° long on March 3d, and from the end of the
forked tail, and from its _north_ side, a streamer diverged at an angle
of 6° or 7° to the _north_. As this was contrary to the _direction_ of
the curvature, if the tail had been curved, it could only arise from a
portion being driven off by the radial stream, or bent towards the plane
of the ecliptic. The curvature observed by others at a later date, was
concave to the south. Towards the middle and close of March, the tail
became straight, and with the above exception, might be considered to
move in the plane of the orbit.
The celebrated comet of Halley, as observed by Dr. Bessel in 1835,
showed that a more or less well-defined tuft of rays emanated from that
part of the nucleus which was turned towards the sun; and the rays being
_bent backward_ formed a part of the tail. The nucleus, with its
emanations, presented the appearance of a burning rocket, the end of
which was turned sideways by the force of the wind. And, Bessel
concludes: "That the cone of light issuing from the comet deviated
considerably both to the right and left of the true direction of the
sun, but that it always returned to that direction, and passed over to
the opposite side; so that the cone of light, and the body of the comet
from whence it emanated, experienced a rotatory, or, rather, a vibrating
motion _in the plane of the orbit_." It is impossible that Bessel should
here mean that this motion was certainly in the plane of the orbit; for
the orbit was then viewed sideways, and he had no means of ascertaining
the fact. His meaning must be that it was apparently in the plane of the
orbit. If a plane be made to pass through the earth, the comet, and the
sun, the tail might be placed in any position in that plane, and yet
appear to be at the intersection of the two; that is, in the plane of
the comet's orbit. The vibration of the tail, in this case, is another
strong proof of the correctness of our theory. To make it more
intelligible, we shall resort to a diagram.
In the following diagram, the comet's orbit, represented by the dotted
line, is drawn on the plane of the ecliptic; it is, therefore, necessary
to bear in mind, that it is tilted up from the line of nodes SN, at an
angle of 17° 45′. The position of the comet, October 9th, is at C,
approaching its perihelion; that of the earth at the same time at T;
while S represents the sun, and SQ the line of equinoxes. Now, from a
cause already explained, the tail always tends to lay behind the comet,
in the direction indicated by the lower tail in the diagram at 1, and,
if produced, would pass to the left of the sun, as seen from the earth:
the force of the radial stream, however, will not allow this lagging of
the tail, and it is straightened out by this force; but, being directed
to the axis of the vortex, and not to the sun, it is not really in the
plane of the orbit, but is seen in the direction of the upper tail
depicted in the diagram at 3, and, if produced, would pass to the right
of the sun, as seen from T. Now, there is an intermediate position of
the tail, in which it will appear in the prolongation of the radius
vector SC; this position is represented by the middle or central tail of
the comet at 2, yet this is not in the plane of the orbit, it only
appears to be, as may be readily understood by remembering that the
earth at this time is under this plane, and the comet is seen at a
considerable elevation above the plane of the ecliptic. When the comet's
tail becomes directed to the axis of the vortex, or in the _apparent_
position of No. 3, the comet, rapidly careering on its way to the sun,
again leaves the tail behind, and again it is strengthened out by the
radial stream oscillating about the mean position at 2, as observed by
Bessel. From this, it appears, that there is no necessity to make
confusion worse confounded, by resorting to polar forces, which are
about as intelligible as the foundations of the pillars of Atlas.
[Illustration: Fig. 25]
It may be objected that the continued action of the radial stream with
that velocity we have contended for, ought to keep the tail invariably
directed from the axis of the vortex; but, where there are two forces or
tendencies, as in this case, analogy would teach us that a certain
degree of oscillation is a necessary result. There may, also, be slight
and transient changes in the direction of the radial stream. In the
hurricane there are short and fitful blasts inclined to the general
direction of the wind, which must arise from the inertia of the moving
mass of atmosphere, causing temporary condensations and rarefactions. Be
this as it may, we have assigned a cause which satisfies the phenomenon,
without coming into collision with a single principle of celestial
mechanics.
Prof. Struve compared the tail of this comet to a flame, or "ray of fire
shot out from the nucleus, as from some engine of artillery, and driven
on one side by the wind." At the same time, he saw a second emanation
nearly in the opposite direction. This last might arise from a momentary
fluctuation in the relative intensities of the electric radiation of the
comet, and of the radial stream, owing to the probable irregularities
just alluded to. Such and kindred phenomena are utterly inexplicable,
without we adopt the theory we are advocating. One other feature, and we
will leave the subject.
From our explanation of the solar spots, we inferred the existence of
another large planet in the system. Might not the same effect be
produced by a comet? Or may there not be so many comets, whose great
elongation, combined with even a moderate mass, may render it impossible
to calculate the position of the sun with respect to the central axis of
the vortex,--always considering this last as the axis of equilibrium? In
a general way, we might say that the very number of comets in all
directions and all distances, would tend to neutralize each other's
effects; but we are not under this necessity. A comet, moving in a
parabola, does not belong to the system or to the rotating vortex; and
the periodic comets, if of gaseous elements, (as seems so probable,)
must, from the size of their nuclei, which the theory considers the only
part constituting their mass, have far less mass than the very smallest
of the asteroids, and consequently could have very little effect on the
mechanical balance of the vortex, even if elongated as far as the orbit
of Neptune. Did we know the influence of cold in limiting the
expansibility of the elementary gases, we might approximately determine
the mass of a comet, from the size of its nucleus; but this is a problem
that has never yet been solved; and astronomers ought to avail
themselves of every indication which promises to realize this great
desideratum. The grand comet of 1556 is now probably approaching, and,
from recent investigations, it appears that it will arrive at its
perihelion in 1858,--subject to an error either way of about two years.
An opportunity may thus be presented of determining the mass of one of
the largest comets on record, which may not again occur. This arises
from the possible appulse of the comet to the planet Pallas, whose mass,
being so small, would more sensibly be disturbed by such an appulse than
the earth. As the inclinations and ascending nodes of the two orbits
approximately coincide, and as Pallas will be near the comet's path, on
the approach of the latter to the sun, at the beginning of the year
1857, should the comet become visible about that time, a very close
appulse is possible. It is not unlikely, also, that if the elements of
Pallas were so far perfected as to afford reliable indications, that the
near approach of the comet might thus be heralded in advance, and lead
to an earlier detection of its presence. Would it not be a worthy
contribution to science, for some one possessing the necessary leisure,
to give an ephemeris of the planet for that epoch; as a very slight
change in Mr. Hind's elements of the comet, would cause an actual
intersection of the two orbits in about heliocentric longitude 153°? The
subsequent nodal passage of Pallas will take place near opposition, and
be very favorably situated for determining the instant of its passage;
and, of all the elements, this would be more likely to be affected than
any other.[47]
THE ZODIAL LIGHT.
A phenomenon, akin to that which we have just been considering, is
presented by that great cone of diffused light which accompanies the
sun, and which in tropical climes displays a brilliancy seldom witnessed
in high latitudes, on account of its greater deviation from the
perpendicular. Sir John Herschel conjectures that it may be "no other
than the denser part of that medium, which, as we have reason to
believe, resists the motion, of comets,--loaded, perhaps, with the
actual materials of the tails of millions of those bodies, of which they
have been stripped in their successive perihelion passages, and which
may be slowly subsiding into the sun." If these materials have been
stripped, it is due to some force; and the same force would scarcely
permit them to subside into the sun. Once stripped, these portions must
be borne outwards, by the radial stream, to the outer verge of the
system. Still, there are, no doubt, denser particles of matter, of the
average atomic density of Mercury and Venus, which can maintain their
ground against the radial stream, and continue to circulate near the
central plane of the vortex, in all that space between the earth and the
sun. But if the zodial light be the denser part of that medium, which
astronomers now generally recognize as a resisting medium, how happens
it that it should be confined to the plane of the ecliptic? Why should
it not be a globular atmosphere? Here, again, our theory steps in with a
triumphant explanation; for while it permits the accumulation of such
particles around the equatorial plane of the sun, it allows no
resting-place very far removed from this plane. The zodial light,
therefore, is not the resisting medium, but the passage of the radial
stream through a diffuse nebula of atoms, brought down the poles of the
vortex by the polar current, and held in check along the central plane
by gravitation.
If these atoms partook of the velocity of the ether, they would not be
luminous; but being held back by gravitation, they are opposed to the
radial stream, and hence the light.
Many stars are also nebulous. In some cases we see the nebulosity
edgewise, or along the equatorial planes of the stellar vortices; in
others we look down the poles, and the nebulosities are circular, and
there is an endless variety in the shape and intensity of this light.
But the universe seems full of motion, and we are not justified in
supposing, because a star shows no such light, that it is without
rotation. The parallax of the nearest star is only one second, the whole
lenticular mass of light which surrounds our sun would therefore only
subtend an angle of a single second at the nearest fixed star. Seeing
its extreme faintness, therefore, the effulgence of the star would
render it totally invisible, provided that it _could_ traverse the vast
immensity of intervening space, without feeling the influence of that
extinction, which Struve has proved does actually diminish the number of
visible stars.
Corruscations and flickerings have also been noticed in the zodial
light, and as usual, the learned have suggested atmospheric conditions
as the cause, instead of trusting to the evidence of their own senses.
How prone is philosophy to cling to that which is enveloped in the mist
of uncertainty, rather than embrace the _too simple_ indications of
nature. As if God had only intended her glories to be revealed to a
favored few, and not to mankind at large. Blessed will be the day when
_all_ will appreciate their own powers and privileges, and no longer
regard the oracles which emanate from a professional priesthood, whose
dicta have so often tended to darken the simple counsels of truth! To
set the question of pulsations in the zodial light, as well as in the
tails of comets, at rest, only requires previously concerted
observations, in places not very widely apart; for it is scarcely
possible, that atmospheric conditions should produce simultaneous
pulsations in two distant places. If the pulsations are found to be
simultaneous, they are real; if not simultaneous, they may depend on
such conditions; but from the nature of the cause, we should look for
them as much in the zodial light, as in the aurora borealis, regarding
the different intensities.
There is also reason to suspect that the northern side is always the
brightest, both in spring and autumn. On the morning of October 4th,
1853, the light was very vivid and well defined, its northern margin
grazing Regulus and terminating at Mars, which was also to the north of
it. Now, although the _northern side_ was the brightest, the great mass
of light was to the south of the ecliptic, as far down as the cone shape
was preserved; but at 10° from the horizon, a still brighter mass
protruded from the cone towards the north, which was all _north_ of the
ecliptic, and of an irregular form, extending along the horizon. The
time was 4 A.M., and consequently was not due to any crepuscular light.
An explanation of the general fact of the brightest light being _always_
on the north side, is given in the present section, in connection with
another phenomenon. If, as some suppose, the light does not reach to the
sun, the annulus must at least fill all the space between Venus and the
earth, but it is far more in accordance with facts as well as with our
theory, to suppose it increases in density to the body of the sun.
Observations made at the observatory of the British Association,
detected, in 1850, sudden brightenings of the light, altogether
different from pulsations. The theory would refer these to that fitful
irregularity in the momentary intensity of the radial stream, which
gives the flickering and tremulous motion to comets' tails. But, the
steady variations in the intensity of this light must be due to other
causes. The longitude of the sun will here come in as a modifying cause;
for the obstruction caused by the body of the sun, when displaced from
the axis of the vortex, must necessarily exercise an influence on the
force and direction of the radial stream. A sudden influx of cometary
matter down the poles of the vortex, in more than usual quantities, will
also tend to brighten and enlarge the zodial light; and, in this last
cause, we have an explanation not only of ancient obscurations of the
solar light, but, also, of those phosphorescent mists, such as occurred
in 1743 and 1831, rendering moonless nights so light that the smallest
print could be read at midnight.
In total eclipses of the sun, the denser portion of the zodial light is
visible as a brilliant corona; but, on such occasions, the brightest
stars only are to be seen, and, consequently, the fainter portions of
the light must be invisible. Hind mentions as many as ten stars visible
in the total eclipse of 1842. According to the same authority, the color
of the corona was like tarnished silver, and rays of light diverged in
every direction, and appeared shining through the light of the corona in
the total eclipse of 1851. In this year on the day of the eclipse (July
28th), the longitude of the sun was about 340°, and, therefore, the body
of the sun obstructed the radial stream as seen from the earth on the
right side; but, in 1842, the longitude of the sun was, according to our
table, about 116°, the sun's centre then being 700,000 miles from the
axis of the vortex, and on the opposite side with respect to the earth;
the position was, therefore, not so favorable for the appearance of
these rays which, in many cases, have given the appearance of a whirling
motion to the corona.
At this date, July 7th, 1842, the corona, according to Prof. Airy,
"possibly had a somewhat radial appearance, but not sufficiently marked
to interfere with the general annular structure." Mr. Baily, on the
contrary, says, the corona had the appearance of brilliant rays; and, at
Milan, long jets of light were particularly noticed. There can be no
doubt but that the passage of the radial stream past the outer margin of
the moon must also give rise to the same phenomena as when passing the
sun, and in this we have an explanation of the fact, that, previous to
the moment of first contact, an appearance resembling a
faintly-illuminated limb of the moon, has been perceived near the body
of the sun; as well as of those flashes of light which have been
observed in the lunar disc as the eclipse advances. One important fact,
worthy of note, is, that these luminous streaks are more nearly parallel
than is due to a radiation from the centre. These streaks have, also,
been seen bent at right angles at the middle of their height, as a flame
is by means of a blowpipe, precisely analogous to cometary rays being
driven backwards to form the tail, as already described, thus indicating
a common origin. If the moon had an atmosphere, we should, no doubt, see
a greater display; but, having no rotating vortex to protect her from
the radial stream, her atmosphere must have been long since stripped
off, leaving her exposed to the withering winter blast of the great
stream of the solar vortex. In this connection, we may also allude to
the appearance of the moon when totally eclipsed. Instead of
disappearing at these times, she sometimes shines bright enough to
reveal her smallest spots. This has been generally referred to the
refraction of the earth's atmosphere bending inwards the solar rays. May
it not be owing to the brilliancy of the solar corona, which, in 1842,
was described as so intense that the eye was scarcely able to support
it? This is a far more palpable cause for the production of this
phenomenon, but of which astronomers cannot avail themselves, as long as
they are uncertain of the origin of this corona.
SHOOTING STARS.
The continual influx of cosmical matter into the heart of the vortex in
ever-varying quantities, and speedily dispersed along the central plane,
according to its density, must necessarily give rise to another
phenomenon to which we have not yet alluded. Scarcely a night passes
without exhibiting this phenomena in some degree, and it is generally
supposed that the hourly average of shooting stars is from five to ten,
taking the whole year round. The matter composing these meteors we
regard as identical with that mass of diffused atoms which forms a
stratum conforming to the central plane of the vortex, and whose partial
resistance to the radial stream occasions that luminosity which we call
the zodial light. These atoms may coalesce into spherical aggregations,
either as elastic gas, or as planetary dust, and, passing outward on the
radial stream, will occasionally become involved in the vortex of our
own globe; and being drawn inwards by the polar current, and acted on by
the earth's gravity, be impelled with great velocity through the
rarefied air of the upper atmosphere. That meteors are more abundant
about the time of meridian passage of a vortex (or, perhaps, more
correctly speaking, from six to twelve hours afterwards, when the
current of restoration penetrates the atmosphere), well accords with the
author's observations. It is about this time that high winds may be
looked for, according to the theory; and it has ever been a popular
opinion, that these meteors are a sign of windy weather. Even in
Virgil's time, the same belief prevailed, as a passage in his Georgics
would seem to indicate.
"Sape etiam stellas, vento impendente, videbis
Præcipites cœlo labi; noctisque per umbram
Flammarum longos à tergo albescere tractus;"
Virgil was a close observer of nature, and commences a storm with the
wind at south, "Quo signo caderent Austri;" just as we have represented
the usual course when these vortices pass near the observer's latitude.
It is also a well-known fact, that after a display of meteors, (and we
are now speaking of ordinary displays, and not of the great showers,)
the temperature falls considerably. It is not uncommon also, that
meteors are more abundant during an auroral display, as they ought to be
by the theory. We must, however, exempt from this influence those solid
meteors which sometimes come into collision with the earth, and
afterwards grace the cabinets of the curious. These bodies may be
considered microscopic planets, moving in stated orbits with planetary
velocity, and bear strongly on the explosive theory of Olbers, as fully
detailed by Sir David Brewster.
It is a very remarkable fact, first noticed by Olbers, that no fossil
meteoric stones have yet been discovered. If this fact be coupled with
the hypothesis advanced by Olbers, in reference to the origin of the
asteroidal group, we should have to date that tremendous catastrophe
since the deposition of our tertiary formations, and therefore it might
possibly be subsequent to the introduction of the present race into the
world. May not some of the legendary myths of the ancient world as
mystified by the Greeks, have for a foundation the disappearance of a
former great planet from the system? The idea of the existence of seven
planets is one of the oldest records of antiquity; but the earth of
course would not be counted one, and therefore in after times, the sun
was included to make up the number; just as the signs of the Zodiac have
been explained in accordance with the seasons of far later times than we
can possibly assign for the invention of this division of the heavens.
Let those who have the leisure, try how far the contraction and dilation
of the asteroidal orbits, to some average mean distance, will restore
them to a common intersection or node, as the point of divergence of the
different fragments. The question is interesting in many of its aspects,
and may yet be satisfactorily answered.
The composition of aërolites may also be taken as indications of the
common origin and elementary texture of the planets, whether they are
independently formed or have originally pertained to a former planet;
for no hypothesis of telluric or selenic origin yet advanced, can stand
against the weight of evidence against it. Their fragmentary character
rather favors the views of Sir David Brewster, and when we consider that
they have been revolving for thousands of years with planetary velocity,
and in very eccentric orbits, through the ether of space, continually
scathed by the electric blast of the radial stream, their rounded
angles, and black glossy crust of an apparently fused envelope, may be
accounted for, without difficulty, from the non-vitrified appearance of
the interior. The composition of aërolites as far as known, embrace
nearly one-third of all known simple substances according to Humboldt,
and are as follows: iron, nickel, cobalt, manganese, chromium, copper,
arsenic, zinc, potash, soda, sulphur, phosphorus, and carbon.
The theory we have thus given of the common occurrence of shooting
stars, will render a satisfactory general account of their sporadic
appearance; but there are other phenomena of greater interest, viz.: the
occasional recurrence of swarms of such meteors, which defy all
numerical estimates, being more like a fiery rain than anything they can
be compared to. The most interesting feature of this phenomena, is the
_apparent_ periodicity of their return. In the following table we have
set down the most remarkable epochs mentioned by Humboldt, (and no man
has devoted more attention to the subject,) as worthy of notice:
About April 22 to 25
" July 17 to 26
" August 9 to 11
" November 12 to 14
" November 27 to 29
" December 6 to 12
Besides these, he mentions two showers, from Arabian authority, in
October; one in October, observed in Bohemia; one observed by himself,
in the Pacific, on March 15; one February 4, just preceding the terrible
earthquake of Riobamba, in 1797. The Chinese annals also contain many
showers of stars, before the present era commenced. Some were in March,
more in July, and others in different months. How, then, in view of
these numerous dates, can we attach so much importance to the
periodicity of these showers? The great shower of 1833, in the United
States, on the 12th and 13th of November, brought to mind the great
shower at Cumana, observed by Humboldt and Bonpland just thirty-three
years before, to a day; and it must be confessed that more than ordinary
displays have been seen on this date. Yet, on the strength of this,
every meteoric shower is supposed to be periodical, and has resulted in
a theory which becomes more complicated as the phenomenon is more
observed, and can never lead to any useful and practical results. To
cite the numerous instances of discrepant results, would only encumber
this brief notice with facts neither interesting to the general reader,
nor convincing to those who hold a contrary opinion. The author of these
pages has watched for many years, and, in view of all the facts, has
concluded that the doctrine of periodicity (as held by present
meteorologists) is not tenable. The celebrated August shower failed,
also, this year, at least in this place, as for four hours each night,
on the 9th, 10th, and 11th, there were fewer bright meteors than at the
close of July.
Professor Olmsted, who has paid considerable attention to the subject,
has indeed attempted to connect the great November shower with the
zodial light, which last he considers a nebulous body, of an elongated
form, whose external portions, at this time of the year, lie across the
earth's path. (See Silliman's Journal for 1837, vol. xxxiii. No. 2,
p. 392.) He even gives its periods, (about six months,) the aphelion of
the orbit being near the earth's orbit, and the perihelion within
Mercury's. In this way he attempts to explain both phenomena; but as the
zodial light is seen unchanged all the year round in tropical latitudes,
it is not the kind of body supposed by Olmsted, and the theory adds
nothing to our knowledge. Others have imagined rings of nebulous matter,
in which all the separate parts are moving in the same orbit around the
sun, with a retrograde motion, and this, with some modifications, is the
current theory of the day. The principal arguments rested on, for the
support of this view, are derived from the great shower of 1833, in
which a common radiant point was observed, and confirmed subsequently by
the radiant of other years, in the same month of November. As this point
is almost tangential to the earth's orbit at this season, the earth
meets the nebulous ring moving in the contrary direction, and thus
confers on these meteors the necessary velocity that is thought to be
demanded by observation.
Now, our theory gives a totally different explanation of the phenomenon.
We contend that a retrograde motion of such a nebulous mass, is
subversive of our whole theory; and we must be permitted to examine
certain points, hitherto disregarded by those entertaining antagonist
views. It is supposed that the meteors in 1833 fell for eight or nine
hours. The orbital velocity of the earth is more than 1,000 miles per
minute, and the orbital velocity of the nebulous zone must have had a
similar velocity. During the nine hours of meteoric display, therefore,
the earth traversed 500,000 miles of her orbit, which would give
1,000,000 miles for the depth of the nebulous stratum. But if of such
vast extent, how happened it that the only part of the earth in which
these were visible in great density, was the United States, or a space
embraced between the latitudes of 50° and 20° north, and the longitudes
60° and 100° west, (and these are the widest limits,) comprising only
1/40 of the surface of the globe? To a calm inquirer, this difficulty
seems insurmountable. The author was then in the Mediterranean, on deck
the greatest part of the night,--the weather fine, and nothing unusual
visible in the heavens; from other sources he has also derived similar
information. Yet, were the earth then passing through a stratum of
meteors 1,000,000 miles in extent, it is utterly inconceivable that
other portions of the earth escaped. Much stress is also laid on the
fact that these meteors in 1833, passed from east to west generally, as
they ought to do, if tangential to the earth in her orbit; but on the
same phenomenon occurring in 1799, when the earth was in precisely the
same part of her orbit, Humboldt says distinctly, "the direction (of the
meteors) was very regular from north to south." How could this possibly
happen, and at the same time be moving tangentially to the orbit?
There is also another fact of importance not duly weighed in forming
such a theory. In 1833 the meteors evidently differed in velocity; one
class, consisting of luminous points, passed like a shower of fire with
great velocity to the westward, another class were like large fire-balls
with luminous trains moving with less rapidity, while a third class
consisted of nebulous patches which remained stationary for a long time,
and frequently emitting large streams of light. These last, at least, do
not deport themselves as planetary bodies moving 2,000 miles per minute.
But the fact still remains, that unusual displays have occurred about
the 12th and 14th of November; and also as a general thing when there
are no unusual displays, the meteors are more abundant about this time.
Let us try if we can reconcile these facts with the theory of vortices.
We will first confine our remarks to the increased number of meteors
about November 12th and 14th. The cosmical matter composing the zodial
light, or at least the lighter parts of it, is continually driven
outwards by the radial stream, just as the matter of a comet's tail is
stripped from the nucleus. This matter becomes involved in the terral
vortex by descending the poles, and is again passed out along the
equatorial plane. The form of the zodial light, as seen edgewise, gives
a lenticular form for the stratum of planetary particles composing it,
and its central plane has been considered as coinciding with the plane
of the sun's equator. At the orbit of the earth, this lenticular space
is narrowed to a very thin stratum, but undoubtedly reaches beyond the
earth's orbit with a rapidly diminishing density. As the axis of the sun
is inclined about 7° to the ecliptic, and the ascending node is in the
20th degree of Gemini, the earth can only pass through the plane of the
sun's equator about the 12th of December and the 12th of June. If,
therefore, the central plane of the vortex coincides with the plane of
the sun's equator, meteors ought to be more numerous about the dates
above mentioned. But the observed times are on November 12th and 13th.
Now, from actual measurements, a computation has been made by M.
Houzeau, that the elements of the zodial light are materially different
from those of the sun's equator. He fixes the node of the light
(according to Mr. Hind) in 2° heliocentric longitude, subject to an
uncertainty of 12° or 13°, and its inclination to the plane of the
ecliptic, 3° 35′, subject to an uncertainty of about 2°. The truth is,
astronomers have argued the coincidence of the two planes from
considerations connecting the zodial light with the sun's equator, as if
it were a solar atmosphere; but such an atmosphere is impossible, and it
is high time such measures should be taken as will lead to some certain
conclusion. If in the present state of the question, we were to take the
mean, we should find the node in about longitude 40°, which is the
position of the earth on November 2d. But in the absence of
measurements, we will assume, for the sake of argument, that the
ascending node of the central plane of the vortex was, in 1833, in 50°
heliocentric longitude, and consequently the earth was passing through
the meteoric stratum or central plane of the zodial light, on the night
of November 12th. The opposite period of the year is May 12th--a date,
it is true, on which no great shower of stars is recorded, but sporadic
meteors are very plentiful at that time, and what is more important to
observe is, that the 11th, 12th, and 13th of May, are the three noted
_cold days_ which we have before mentioned. Thus truly indicating that
the earth is then in or near the central plane of the vortex along which
the radial stream is at its maximum of power at any given distance from
the axis.
But the question occurs, does the node of this plane remain stationary,
and is there no variation of the inclination of the axis of the solar
vortex? We have found from observation, that the axis of the terral
vortex is continually oscillating about a mean position by the action of
the moon; and reasoning from this analogy, and the constant tendency of
a material vortex to preserve a dynamical balance, the same tendency
must obtain in the solar vortex under the action of the great planets,
whose orbits do not coincide with the central plane of the vortex. The
ascending node of Jupiter's orbit is in longitude 98°, Saturn's 112°,
Uranus' 72°, Neptune's 131°; so that this plane does not correspond with
the plane of greatest inertia discovered by La Place, and from the
non-coincidence of these planes with the central plane of the vortex,
must produce the same oscillation in the axis of the solar vortex, as
the moon does in the terral vortex, but to what amount, observation can
alone determine. Jupiter and Saturn will of course exert the greatest
influence, and when these two planets are in conjunction, the ascending
node of the central plane of the vortex will vary in longitude perhaps
sufficiently to bring the meteoric maximum at the ascending node into
October on the one hand, and to the close of November on the other, and
at the descending node to April 25th on the one hand, and the close of
May on the other.
The great showers of stars which have been recorded, must be therefore
considered as an accidental exaggeration of a perennial phenomenon,
attaining its maximum when the earth passes through the central plane of
the vortex, whose ascending node in 1833 we will suppose was in
longitude 50°. This theory will therefore account for those great
showers which have occurred about the 24th of April, as well as those
occurring in October and November; for it is far more consonant to all
analogy, to suppose the influx of planetary atoms into the solar vortex
to be in irregular, than in regular quantities. Yet, whether in the one
case or in the other, the matter will pass along the central plane of
the vortex, either diffusely scattered or in denser clouds, and will be
encountered by the earth when near the nodes _more frequently than at
other times_. The phenomenon of 1833, may then be attributed to the
earth encountering an unformed comet on the 12th of November; but we
must reflect, that the medium of the vortex is also in motion, and the
cometary matter drifting along with it; and that this motion corresponds
with the earth's motion. By becoming involved in the terral vortex, it
will in a measure be carried along with the earth in her orbit as a
temporary occupant of the terral vortex. But we are here met with the
objection that the radiant being nearly stationary amongst the stars,
demonstrated conclusively, that the source of these meteors did not
partake of the earth's motion. There is no difficulty in this. We
suppose as a general thing, that the meteors descended to the surface of
our atmosphere down the axis of the vortex (at least in the greatest
numbers), and the geocentric longitude of this axis was nearly the same
during the whole time of the display. We say nearly, for the motion of
the moon in her orbit in nine hours, would change the longitude of the
axis three or four degrees, and this is about the change in the
position of the radiant noted at the time. This objection, therefore,
falls to the ground; for the axis of the vortex, although carried along
with the earth in her orbit, was unaffected by the earth's rotation, and
would therefore appear nearly as stationary in the heavens as Gamma
Leonis. But it is again urged, that the moon was near conjunction with
the sun, and consequently the central vortex was on the opposite side of
the globe. This is true; but the outer vortex must have been near the
meridian about three hours after midnight, or about the time when the
radiant was vertical and the display the greatest. When the axis was to
the eastward, the stars would shoot westward, when on the meridian, they
would pass in all directions, but principally to the south, on account
of the inclination of the axis of the vortex; but this would only be
true for places situated to the southward of the central latitude.
During the great shower of stars seen by Humboldt, in Cumana, the
direction was to the south uniformly. Now, the latitude of Cumana is
above 10° north, yet still too low for the general limits of the
vortices; but from the same inclination of the axis (from 30° to 36° to
the surface), the meteors would pass far south of the limit, and might
even reach to the equator. The latitude of the _outer vortex ascending_
on November 12th, must have been near the line of greatest display, from
the position of the moon at the time. We thus see why the phenomenon was
limited to so small a fraction of the earth's surface; why these meteors
should be intermingled with nebulous patches stationary in the heavens
for an hour together, and why, notwithstanding these facts, they were
independent of the earth's rotation.
We have yet another objection to answer, viz.: the planetary velocity of
some of these bodies. Let us be understood. The velocity of a solid
aërolite is due to gravitation, and is planetary, on the other hand,
voluminous collections of cometary dust united by accident, and
remaining so by mere inertia, are borne passively on the ethereal
currents with _electric_ velocity, and probably never penetrate far,
even into the attenuated atmosphere, which may be supposed (from the
facts connected with the aurora) to extend far above the denser stratum
which refracts and reflects light, and from which the assigned limits of
our atmosphere have been derived.
It is generally considered that sporadic meteors are more numerous in
the summer and autumn than in the winter and spring, and we have,
likewise, in the tenth of August, a date which corresponds to many great
displays and meteoric showers, both in recent and remote times. This
would seem to vitiate our theory; for we cannot suppose that there are
two _central_ planes in the vortex intersecting the ecliptic in
longitude 320° and 50°. We must remember, however, that as these great
displays are accidental, and as the stratum composing the zodial light
is manifestly of sufficient thickness to envelope the whole orbit of the
earth, that it does not necessarily follow that the dense portions to
which meteoric showers are due, should be always confined to the central
plane of the vortex. And, besides, we have similar displays recorded in
other months, which invalidates the theory of a regularly-recurring
phenomenon. We shall, therefore, only aim at explaining why meteors are
generally more abundant in summer and autumn than in the opposite
seasons.
The axis of the solar vortex, considered as cylindrical, must be
admitted to run out to a great depth on either side from the sun, and
reach far into that unoccupied space intervening between our system and
the nearest fixed stars, and from these opposite points the solar vortex
is supplied with that stream of ether which passes down either pole to
restore a partial equilibrium in the density of the ether of the vortex,
rarefied by centrifugal force. As certain portions of the heavens are
crowded with stars, and other parts comparatively vacant, we may expect
a similar inequality in the distribution of that cometic dust, which
causes a certain amount of extinction in the light of the stars, and,
therefore, seeing that the two extremities of the axis of the solar
vortex are so widely separated, it would not be wonderful if different
quantities of such matter were brought down into the vortex from these
extremities.
From recent observations made by H. R. Birt, at the observatory of the
British Association, it would appear that the brightest portion of the
zodial light is always north of the ecliptic. Others have also remarked
the same, and if we couple this fact with the suggestion just made, we
are justified in suspecting that a greater quantity of cometic dust
comes down the northern pole of the vortex than down the southern. This
matter, in passing outward, does not, of course, immediately attain to
the central plane of the vortex, but is more thickly distributed along a
plane parallel to this plane. And the same will be observed by that
matter coming down the southern pole; it will be, in a certain degree,
retained in a plane south of the central plane, but still parallel with
it. This would account for the greater brightness of the northern side
of the zodial light. It would, also, account for the greater frequency
of meteors in summer and autumn than in the opposite seasons. From May to
November the earth is above the central plane of the vortex, and,
consequently, on the northern side; but after passing the node in
November, she is on the under or southern side, and the meteors are less
frequent. With this general explanation we shall close. If what we have
advanced be an approximation to the truth, the theory itself affords
ample indications of what observations are requisite to prove or
disprove it; and, on this account, a theory is of great benefit, as
suggestive of many questions and combinations of facts which otherwise
might never be thought of.
We have thus taken a cursory glance at the prominent physical phenomena
of the world, and attempted to link them together in the bonds of one
all-pervading principle. We have fearlessly taken a new path, and claim
originality for the whole, disclaiming all intention of retailing
second-hand wares, or of compiling an ingenious theory from
heterogeneous scraps. If it be true, or if it be partially true, let
those professionally engaged in such pursuits enter the wide field of
investigation we have discovered for them; for if the whole theory be
true, it only shows in a clearer light that the great work which has
been fancied so near completion is scarcely yet begun; while the
prospect of an ultimate and final completion of the temple which so many
zealous votaries are erecting, is rendered mournfully hopeless by the
contemplation of what yet remains to be performed.
FOOTNOTES:
[42] The orbit this year was determined under very unfavorable
circumstances.
[43] According to other tables, this angle would be much greater than is
given in Mr. Hind's catalogue.
[44] Prin. Prop. xx Lib. Sec.
[45] With reference to the resisting power of the atoms.
[46] Prin. Lib. Tor. Prop, xxxix., also Prop, xli.
[47] In making this suggestion, the author is well aware that
Ephemerides of the four chief asteroids have been given annually in the
Greenwich Nautical Almanac; but for the object proposed they are utterly
useless. Will any astronomer contend that these Ephemerides are true to
ten seconds of arc? If not, they are useless for the purpose suggested
above, and the theory wants revision. And it is evident that any
objection against its practicability, founded on the uncertainty of the
number of the asteroids themselves, as has already been urged in answer
to this suggestion, is an evidence that the objector weighed the subject
in the scales of his imagination only.
SECTION SIXTH.
THE POLAR ICE.
We shall conclude these pages by again referring to our theory of the
weather, in connection with an event which every friend of humanity and
every lover of natural science is bound deeply to deplore.
From the present position of the lunar nodes and apogee, the vortices of
our earth do not ascend into very high latitudes. Now, according to the
principles laid down, the frequency of storms tends to lower the
temperature in the warm regions of the earth, and to elevate it in the
polar regions. Let us suppose the northern limit of the vortices to be
in latitude 70°. There will be, in this case, a greater prevalence of
northerly winds _within_ this circle of latitude, to supply the drain to
the southward, and the back currents by passing above will descend at
the pole, partaking of the temperature due to that elevation. The
character of the arctic seasons may therefore be considered as partly
dependent on the average direction of the wind. Suppose again, the
extreme limits of the vortices to be about latitude 80°, the relative
areas of the two circles are as 4 to 1; so that in this last case the
exclusive range of the northerly winds is limited to one-fourth of the
first area. South of 80° the wind will frequently come from the south,
and by mixing with the local atmosphere of that latitude, will tend to
ameliorate the small area to the northward. And the greater atmospheric
commotion when confined to such a small circle of latitude, must assist
materially to break up the polar ice; which would tend still more to
equalize the temperature.
By referring to our table, we see that the mean conjunction of the pole
of the lunar orbit and the moon's apogee, was in longitude 128° on April
10, 1846, and let it be remembered that when the conjunction takes place
due south or in longitude 270°, the vortices attain their greatest
latitude north. When, on the contrary, the conjunction takes place due
north or in longitude 90°,[48] the northern limits of the vortices are
then in the lowest latitude possible.
Sir John Franklin sailed in May 1845, and was certainly at the entrance
of Wellington sound, near latitude 75°, April 3d, 1846, as the dates on
the graves testify. That season, according to the theory, was a cold
one; for the vortices could not reach so far to the northward in that
year, and consequently there were no storms, properly speaking. It would
probably be late in the summer of 1846, before the expedition was
liberated, and as the prevailing winds would be from the northward, he
would have little choice, but to stand to the westward if the state of
the ice permitted. In his instructions he was to use every effort to
penetrate to the southward and westward of Cape Walker, and he probably
conformed to them under the circumstances, and passed the winter in the
ice, in that neighborhood. And in 1847 we do not anticipate, from the
theory, that he would make much progress westward.
In 1848, Sir James Ross was sent out with the first relief-ship; but was
not able to reach the entrance of Wellington channel because of compact
ice from there to Leopold Island. This was about the beginning of
September--a time when the northern channels are usually the most open.
On the 11th, they ran the ships into Port Leopold, and the next day the
ice shut them in for the winter. From the character of the season, we
may infer that if Franklin did not enter Wellington channel in 1847, as
is most probable, neither did he in 1848. Perhaps he was not able to get
his ships far to the westward, as we infer from the theory. Still, as
the time was not very protracted, he would wait patiently another season
and husband his resources.
In 1849, Sir James Ross cut his ships clear of the ice August 28th, and
crossed over to Wellington channel, where he found the land-ice still
fast, showing that this season was also a bad one in accordance with the
theory. On the 1st of September he met the first gale of wind, at which
time the _Inner Vortex_ was at its extreme north latitude, and rapidly
extending its limits by the motion of the perigee.
This vortex describes a smaller orbit than either the central or the
outer vortex, and consequently reaches into higher latitudes. But the
time was badly chosen, as the whole series of years since Franklin left
has been unfavorable for the early rupture of the ice. Sir James Ross
having been drifted out of Lancaster sound by the gale, finally bore up
for England towards the close of September 1849.
The same year, the North Star with additional supplies was working up
Baffin's bay; but on account of the unusual quantities of ice, and the
frosts "which glued the floes together," she was unable to force a
passage through the middle ice, and wintered on the east side of
Baffin's bay, in latitude 76° 33′--her thermometer marking 64° below
zero, as the coldest of the winter. In 1850, the perigee of the moon
attained its northern limit, but the position of the node was bad; still
this year and 1851, were the best of the series. The North Star
succeeded in getting out of the ice on the 1st of August--a very early
date for that high latitude--and on the 8th had crossed over to
Possession bay; but being prevented by the land-ice, she bore up for
Pond bay and there landed the provisions. The same year (1850) several
vessels entered Lancaster sound. Sir John Ross also reached Melville
Island; from which it is evident that this season was far better than
any preceding. According to Captain Penny, this year a floe of ice at
least two years old, filled Wellington strait; but was diminished in
breadth at a subsequent visit. He also saw a boundless open sea from the
_western_ entrance of Wellington strait; but of course the ships could
not reach it, for the floe before mentioned. Following the indications
of the theory, we consider it almost certain that Franklin went to the
westward and not through Wellington channel; that he made but slow
progress until 1850, when finding the sea more open to the northward,
and attributing it more to local influences than to any change in the
season, he considered it a better course to extricate the expedition, by
pushing on towards Behring's straits than to attempt the frozen channels
he had already passed through. But the seasons again getting worse after
1850, he was again arrested in the polar basin by the ice and islands
off the northern coast of America.
Regarding the old and new continents as in reality a connected body of
land, with a polar depression, we may expect that the great range of
American mountains is continued in a straight line, from the mouth of
the McKenzie river, obliquely across the Polar sea, and connects with
the Ural; and that along the axis of the chain, protuberant masses will
emerge above the sea level, constituting an archipelago of islands, from
Nova Zembla to the McKenzie; and that these islands, causing an
accumulation of ice, and arresting its general tendency to the
southward, is the barrier which Sir John Franklin was finally stopped
by, in a situation where he could neither advance nor return. With the
map before us, and the data afforded by former voyages, and guided by
these theoretical views, respecting the prevailing direction of the
winds and the character of the seasons, we should locate Sir John
Franklin near latitude 80°, and longitude 145°, in 1851; and as the
seasons would afterwards become more severe, we may consider that he
has not been since able to change his locality, and dare not desert his
ships.
No mere stranger can feel a deeper interest than the author, in view of
the hard fortunes of these hardy explorers, and he would not lightly
advance such opinions, did he not suppose they were in some degree
reliable. In 1832, he himself crossed the Atlantic, for the purpose of
offering himself to the Geographical Society of London, intending to be
landed as far northward as possible, with a single companion,[49] from
which point he purposed to follow the coast line on foot, with cautious
discretion as to seasons, confident that, with arms and ammunition, he
could support himself for many years. It has always been a grave error
in all these northern land expeditions, that they have been too
unwieldy, too much encumbered with the comforts and luxuries of
civilization at the outset, and too much loaded with a philosophical
paraphernalia, for a pioneering survey,--and cherishing too fondly the
idea that the wide shores of the Arctic sea could be explored in a
single season. Had the British government established a few posts in the
Arctic regions in the beginning,--one, for instance, in Lancaster sound,
another in Behring's Straits, and a third near the mouth of the
Coppermine, volunteers of sufficient scientific attainments might have
been procured, to banish themselves to these inhospitable regions for a
term of years, if assured of triennial supplies; and in this way, by
summer boat-parties and winter expeditions, over land or ice, the
explorations could have been gradually extended, and a greater knowledge
of the polar regions might have been acquired, with an immense saving
both of life and money. In 1832 the author's plan was deranged, by
finding that Captain Back was about setting out in quest of Ross, who
had then been some four years absent. This officer had all his party
engaged when the author waited upon him in Liverpool, and no notice was
taken of a modified plan which he forwarded to the Society at his
suggestion. It was therefore abandoned.
The above fact is alluded to, in order to show the author's sincerity in
expressing his belief that, with a previous preparation of mind and body
for a sojourn in those frigid climes, a sufficient subsistence may be
derived from the country itself. Advantage must, of course, be taken of
the times of abundance, and due preparation made for the season of
scarcity. Averaging the extremes, there is little doubt but that both
land, and air, and water, afford an abundance of food for man in the
Arctic zone, and that, when spurred by necessity, it is within his power
to obtain it. We ought not therefore to despond, or give up efforts to
rescue those who have well earned the sympathy of the world, by what
they must have already suffered. _These northern seas will yet be
explored._ The very difficulty of accomplishing it, will itself give it
a charm, which in this restless age will operate with increasing power.
And should efforts now be relaxed, and in some future time the evidence
be brought to light that some of the party yet existed, long after all
efforts to rescue them had been abandoned, the fact would be a dark spot
on the escutcheon of England, which time could not erase.
Since these pages were written, accounts have been received from Captain
McClure, of H. M. ship Investigator, which fully confirm the preceding
remarks on the character of the seasons in the Arctic circle; and, more
recently, despatches have been received from the discovery-ship,
Amphytrite, in relation to the past season in Behring's straits, which
also confirms the theory.
The Investigator (now supposed to be frozen up in lat. 74° 5′ N., and
long 117° 54′ W.,--the last despatch being dated April 10, 1853) passed
round the northern shores of America into the channels communicating
with Lancaster sound, in 1850, but was unable to extricate herself in
1852, and, probably, yet remains in the harbor she made in the winter of
1851, in the position above named. No trace of Sir John Franklin's
expedition was, however, found, and, indeed, according to our theory,
the Investigator was not on the most promising ground. We contend that
Franklin has penetrated the pack of apparently perennial ice, which is
continually pressing to the southward, and blocking up the passages
between the northern islands, or skirting the coast line of the
continent; which pack has since increased, and effectually stopped all
egress from the open central portions of the polar sea. If Sir John
Franklin is ever heard from, this pack _must be penetrated_, and a
powerful steamer ought to be sent immediately by the British government,
to be ready in Behring's straits early enough to take advantage of the
first openings, and make a bold push _due north_, so as to get as
speedily as possible into the open waters to the north of the pack.
If the author could make himself heard at Washington, he would also urge
the government to lose no time in following our own expedition under Dr.
Kane, who, if he finds a clear entrance from Smith's sound into the
Arctic sea, may be induced to push on, and endeavor to make his way
through the pack towards Behring's straits, and thus fall into the same
snare as Franklin. According to the theory, the higher the passage into
the Arctic sea, the less will it be incumbered with ice, and,
consequently, Smith's sound is the best both to enter and return by; and
had the author not already smarted enough by having his professions
derided, he would have submitted these views to the patrons of that
expedition before it sailed.
The scientific world is, in reality, chargeable with the disastrous
results of Franklin's expedition. The polar basin is hemmed in by the
coast line of Europe, Asia, and America, in about latitude 70° north,
for the greatest part of the entire circumference. And this coast line,
and the islands adjacent, will cause the polar ice to accumulate and
form a frozen belt along these shores, in consequence of the constant
tendency of the earth's rotation to press the ice to the southward. The
fact that an open passage exists between this belt and the shore in
summer time, is no objection, as the tides, river currents, and warm
land breezes, may very well explain this. The learned have insisted, and
do yet insist, that the earth's rotation can produce no motions in the
Arctic sea, and, under this delusion, Franklin has passed into the
comparatively open waters inside the pack, perhaps has lost his ships;
yet it is very possible that the party may have escaped, and derived a
subsistence from the more genial waters of the central portion of that
ocean unto this day.
We have already alluded to the difference of level between the Atlantic
and Pacific waters. It is well known that the currents in the
Spitzbergen and Greenland seas is to the southward, and that Parry, in
his attempt to reach the pole, was foiled by this very current,
frequently setting him back in twenty-four hours more than his party
could travel in the same time over the ice. Through Baffin's and
Hudson's bay the northern waters are also continually bearing their
frozen freight southward. We are, therefore, entitled to ask, what
supplies this immense drain? Behring's straits are only about sixty
miles wide, and twenty-five fathoms deep; the supply, therefore, through
this channel is totally inadequate, yet there is no other channel into
the Arctic sea where the current is inward. We have already explained
the reason why the current through Behring's straits is an exception to
the general rule, yet still confirming the principle by referring it to
the configuration of the land enclosing the Pacific ocean. The whole
south Pacific lies open to the pole, and the inertia of the immense mass
of mobile waters pressing northward, and continually contracted by the
form of the American and Asiatic coasts, is not balanced by a contrary
impulse of the waters of the north Pacific, inasmuch as this ocean
becomes narrower as it extends northward, and the only passage to the
frozen ocean is through the narrow straits of Behring. The axifugal
force of rotation due to the northern waters is, therefore, overborne
by the vast preponderance due to the southern waters, and, hence, the
northern Pacific may be considered as relatively at a higher level, and
there will be a current northward through Behring's straits, as we find
it. The same cause accumulates the waters under the equator, thus giving
a higher level to the Pacific than to the Atlantic at the isthmus of
Panama, where the difference of level is found by actual measurement to
be five or six feet. This fact has never before been explained; but the
cause is too obvious to admit of question.
That the sea is deeper than was formerly admitted, is now fully
confirmed. We have before alluded to the results obtained by Captain
Denham, of H. M. ship Herald, who found bottom at 7,706 fathoms, or
about nine English miles. Now, whether that spherical shell, which we
have contended to be the true form of the solid earth, be continuous and
entire; or, whether it may not be wanting in localities of limited
extent where the ocean would be absolutely unfathomable, we know not;
but if such be the internal constitution of our globe, there will be, no
doubt, many channels of communication between the internal and external
ocean, and, as a consequence of the earth's rotation, the axifugal
current of the Arctic sea may be supplied by an upward current from the
interior of the globe; and this current may have a higher temperature
than the surface waters of that sea, and thus the middle portions may,
in truth, remain open the whole year round, and be teeming with animal
life. According to Captain Penny's observations in 1850, whales and
other northern animals existed to the westward, where he saw the open
sea stretch out without a bound before him.
It has been a question mooted by some, that Franklin's ships might be
overtaken, at an early stage of the voyage, by a storm, and foundered
amidst the ice. The theory would give a negative answer to this
question. Stiff gales may prevail far to the north when the vortices do
not reach so high; but no storm, properly speaking, will be found far
beyond their northern limit. After the coming winter (1853), the
vortices will gradually penetrate farther and farther to the northward,
and the years 1857, 1858, and 1859, will be highly favorable for
northern discovery, accompanied, however, with the necessary draw-back
of tempestuous weather.
FOOTNOTES:
[48] The reader will of course understand these as celestial longitudes,
and the latitudes as terrestrial.
[49] Mr. William McDonald, of Canada.
CONCLUSION.
Our theory has thus extended itself beyond those limits which we at
first had drawn, and our apology must consist in the necessity existing
for reconciling the most remarkable phenomena of meteorology to its
principles. Yet, after all, what has been said is but an outline of what
remains, but this outline is a part of our theory of the weather, and it
could not well do without its aid. In some points we may not have
correctly interpreted facts; but the facts remain. The numerical
elements of the theory may also be in error--we know not; but we think
that they are as perfect as the many contingencies on which they depend
will permit. What is _certain_ however, is of ample value to compensate
for trivial errors. We have hitherto experienced but little courtesy
from those intrusted with the keys of knowledge, and cannot consequently
anticipate a very lenient verdict. But we now tell them before the
world, that they have a duty to perform, and an examination to make, and
a decision to come to, "whether these things are so." Our theory may be
called an ingenious speculation, but WE CHALLENGE THE SCIENTIFIC TO
PROVE IT--NOTHING ELSE. The theory furnishes them with tests of daily
occurrence, to prove or to disprove it. By such a trial we are willing
to be judged; but let it be conducted in the spirit recommended in the
opening address before the American Association for the Advancement of
Science, to expose all false developments, and to do it generously and
without prejudice; and to remember, "that the temple of science belongs
to no country or clime. It is the world's temple, and all men are free
of its communion. Let its beauty not be marred by writing names upon its
walls."[50] The _great_ objection, of friction and resistance of an
all-pervading medium, which will be urged against it, we regard as
rather the offspring of a bewildered imagination, than of scientific
induction. We can discover no such consequences as final ruin to our
system through its agency; but even if such were discovered, we may
answer, that nature nowhere tells us that her arrangements are eternal;
but rather, that decay is stamped with the seal of the Almighty on every
created thing. Change may be one of the great laws of matter and motion,
and yet matter and motion be indestructible. The earth was called into
existence for a specific object, and when that object is accomplished,
we are assured that another change awaits her. But when earth, and sun,
and planets, are again redissolved into their primitive state, their
atoms will still float on the ever-rolling billows of the great ethereal
ocean, to be again cast up, on the shore of time, whenever it pleaseth
Him to say, "Let there be light."
FOOTNOTES:
[50] Prof. Pierce's Address, 1853.
APPENDIX.
Since the author's arrival in New York for the purpose of publishing his
outlines, the third and fourth volume of the Cosmos has been placed in
his hands, containing the latest uranological discoveries and
speculations. It is now more than twenty years since he began to
investigate the subject he has treated of, and fifteen since he first
announced to the world, that he had satisfactory evidence of his theory
being true. Luckily, perhaps, he has been cut off from the great streams
of knowledge; and he may confess that it was with pardonable feelings of
gratification that he discovered in 1853, by the acquisition of the two
first volumes of the Cosmos, that the philosophic mind of Humboldt had
also pondered deeply on the planetary peculiarities of size, density,
distance, inclination of axes and eccentricities of orbits, without
eliciting any satisfactory relations.
From the tenor of the third and fourth volume of this learned summary of
scientific knowledge, it is evident that the question of a medium
filling space is more and more occupying the learned world; but the
author is unable to discover any consistent theory respecting it. The
increasing interest attaching to it, however, is evidently preparing the
world for some radical change in preconceived views. The explanation
given by this present theory to many prominent phenomena, is so totally
contrary to that of the learned world, as to leave it untouched by
anything yet advanced. What the fifth volume of the Cosmos will
contain, is not yet known in this country, neither has the author been
favored with any glimpse of the progress of science as developed before
the British Association; he supposes, however, that he yet stands alone
in the position he has defined.
As a question of practical importance, the reader will find in the work
cited, the various opinions of the temperature of space. Both Fourier
and Poisson regard this as the result of radiated heat from the sun and
all the stars, minus the quantity lost by absorption in traversing the
regions of space filled with ether.[51] But why should we regard the
stars as the source of all motions? Why cannot physicists admit the idea
of an infinite space filled (if we may use the expression) with an
infinite medium, possessing an unchangeable mean temperature long before
the formation of a single star. A star equal to our sun at the distance
of Sirius, would give about one million of million times less heat than
our present sun, which is only able to give an average temperature to
the whole globe--about twenty degrees above freezing--then let us
remember that there are only about fifty stars of the first and second
magnitude, which give more light (and by analogy heat also) than all the
rest of the stars visible. Such labored theories as this of Poisson's is
a lamentable instance of the aberrations of human wisdom.
We would also call the reader's attention to a late conclusion of
Professor Dove, viz.: That differences of temperature in different
longitudes frequently exist on the same parallel of latitude, or, in
other words, are laterally disposed. This may be thought adverse to the
theory, but it should be borne in mind that the annual mean temperature
of the whole parallel of latitude should be taken when comparing the
temperatures of different years.
Another fact cited in the Cosmos apparently adverse to the theory, is
the idea entertained by Sir John Herschel, that the full-moon
dissipates the clouds. This question has been fully examined by
Professor Loomis before the American Association, and he concludes that
there is not the slightest foundation for the assertion--taking as data
the Greenwich observations themselves.
FOOTNOTES:
[51] See _Cosmos_, p. 41, vol. III.
*** End of this LibraryBlog Digital Book "Outlines of a Mechanical Theory of Storms - Containing the True Law of Lunar Influence" ***
Copyright 2023 LibraryBlog. All rights reserved.