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Title: The Story of Eclipses
Author: Chambers, George F. (George Frederick), 1841-1915
Language: English
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THE STORY OF ECLIPSES
_SIMPLY TOLD FOR GENERAL READERS._
WITH ESPECIAL REFERENCE TO THE TOTAL ECLIPSE
OF THE SUN OF MAY 28, 1900.
BY
GEORGE F. CHAMBERS, F.R.A.S.
_Of the Inner Temple, Barrister-at-Law._
AUTHOR OF
“THE STORY OF THE SOLAR SYSTEM”; “THE STORY OF THE STARS”;
“A HANDBOOK OF DESCRIPTIVE ASTRONOMY,” ETC.
LONDON: GEORGE NEWNES, LTD.
SOUTHAMPTON STREET, STRAND
1899.
_The rights of translation and of reproduction are reserved._
[Illustration: FIG. 1.—THE TOTAL ECLIPSE OF THE SUN, Sept. 7, 1858
(_Liais_).]
PREFACE.
The present Volume is intended as a sequel to my two former volumes in
the Newnes Series of “Useful Stories,” entitled respectively the “Story
of the Solar System,” and the “Story of the Stars.” It has been written
not only as a necessary complement, so to speak, to those works, but
because public attention is already being directed to the forthcoming
total eclipse of the Sun on May 28, 1900. This eclipse, though only
visible as a partial one in England, will be total no further off than
Portugal and Spain. Considering also that the line of totality will pass
across a large tract of country forming part of the United States, it
may be inferred that there will be an enormous number of
English-speaking spectators of the phenomenon. It is for these in
general that this little book has been written. For the guidance of
those who may be expected to visit Portugal or Spain, a temporary
Appendix has been prepared, giving a large amount of information showing
how those countries can be best reached, whether by sea or overland,
from the shores of England.
If anyone is inclined to doubt whether an eclipse expedition is likely
to provide non-astronomical tourists with incidents of travel, pleasant,
profitable, and even amusing, perhaps the doubt will be removed by a
perusal of the accounts of Sir F. Galton’s trip to Spain in 1860
(_Vacation Tourists in 1860_, p. 422), or of Professor Tyndall’s trip to
Algeria in 1870 (_Hours of Exercise in the Alps_, p. 429), or of
Professor Langley’s Adventures on Pike’s Peak in the Rocky Mountains,
Colorado, U.S., in 1878 (_Washington Observations_, 1876, Appendix III.
p. 203); or of some of the many Magazine and other narratives of the
Norway eclipse of 1896 and the Indian eclipse of 1898.
Subject to these special points no further prefatory explanation seems
needed, the general style of the contents being, _mutatis mutandis_,
identical with the contents of the Volumes which have gone before.
I have to thank my friend, Dr. A. M. W. Downing, the Superintendent of
the _Nautical Almanac_, for kindly verifying the calculations in
chapters II. and III.
G. F. C.
NORTHFIELD GRANGE,
EASTBOURNE, 1899.
CONTENTS.
CHAP. PAGE
I. INTRODUCTION 9
II. GENERAL IDEAS 11
III. THE SAROS AND THE PERIODICITY OF ECLIPSES 18
IV. MISCELLANEOUS THEORETICAL MATTERS CONNECTED
WITH ECLIPSES OF THE SUN (CHIEFLY) 34
V. WHAT IS OBSERVED DURING THE EARLIER STAGES
OF AN ECLIPSE OF THE SUN 40
The Moon’s Shadow and the Darkness it causes 41
Shadow Bands 46
The Approach of Totality 49
The Darkness of Totality 53
Meteorological and other effects 54
VI. WHAT IS OBSERVED DURING THE TOTAL PHASE OF
AN ECLIPSE OF THE SUN 56
Baily’s Beads 57
The Corona 62
VII. WHAT IS OBSERVED AFTER THE TOTAL PHASE OF
AN ECLIPSE OF THE SUN IS AT AN END 73
VIII. ECLIPSES OF THE SUN MENTIONED IN HISTORY—CHINESE 75
IX. ARE ECLIPSES ALLUDED TO IN THE BIBLE 86
X. ECLIPSES MENTIONED IN HISTORY—CLASSICAL 107
XI. ECLIPSES MENTIONED IN HISTORY—THE CHRISTIAN
ERA TO THE NORMAN CONQUEST 128
XII. ECLIPSES MENTIONED IN HISTORY—MEDIÆVAL
AND MODERN 145
XIII. ECLIPSES MENTIONED IN HISTORY—NINETEENTH
CENTURY 162
XIV. THE ELECTRIC TELEGRAPH AS APPLIED TO ECLIPSES
OF THE SUN 179
XV. ECLIPSES OF THE MOON—GENERAL PRINCIPLES 186
XVI. ECLIPSES OF THE MOON MENTIONED IN HISTORY 197
XVII. CATALOGUES OF ECLIPSES: AND THEIR CALCULATION 218
XVIII. STRANGE ECLIPSE CUSTOMS 224
XIX. ECLIPSES IN SHAKESPEARE AND THE POETS 229
XX. BRIEF HINTS TO OBSERVERS OF ECLIPSES 233
XXI. TRANSITS AND OCCULTATIONS 235
APPENDIX—INFORMATION RESPECTING THE TOTAL
ECLIPSE OF MAY 28, 1900, FOR TRAVELLERS VISITING
PORTUGAL AND SPAIN 239
LIST OF ILLUSTRATIONS.
PAGE
FIG. 1. TOTAL ECLIPSE OF THE SUN, SEPTEMBER 7,
1858 _Frontispiece_
" 2. THEORY OF TOTAL ECLIPSE OF THE SUN 15
" 3. THEORY OF AN ANNULAR ECLIPSE OF THE SUN 16
" 4. ANNULAR ECLIPSE OF THE SUN 16
" 5. PARTIAL ECLIPSE OF THE SUN 17
" 6. SHADOW BANDS 47
" 7. RAYS OF LIGHT SEEN DURING TOTALITY 49
" 8. BRUSHES OF LIGHT 57
" 9. “BAILY’S BEADS,” FOUR STAGES, AT BRIEF
INTERVALS (MAY 15, 1836) 58
" 10. CORONA OF 1882. SUN-SPOT MAXIMUM 68
" 11. CORONA OF 1867. SUN-SPOT MINIMUM 70
" 12. ECLIPSE OF JAN. 11, 689 B.C. AT JERUSALEM 100
" 13. THEORY OF AN ECLIPSE OF THE MOON 187
" 14. CONDITIONS OF ECLIPSES OF THE MOON 189
" 15. OCCULTATION OF JUPITER, AUG. 7, 1889
(IMMERSION) 237
" 16. OCCULTATION OF JUPITER, AUG. 7, 1889
(IMMERSION) 237
" 17. OCCULTATION OF JUPITER, AUG. 7, 1889 (EMERSION) 238
" 18. OCCULTATION OF JUPITER, AUG. 7, 1889 (EMERSION) 238
" 19. PATH OF THE TOTAL ECLIPSE OF THE SUN OF
MAY 28, 1900 _at end of book._
THE STORY OF ECLIPSES.
CHAPTER I.
INTRODUCTION.
It may, I fear, be taken as a truism that “the man in the street”
(collectively, the “general public”) knows little and cares less for
what is called physical science. Now and again when something remarkable
happens, such as a great thunderstorm, or an earthquake, or a volcanic
eruption, or a brilliant comet, or a total eclipse, something in fact
which has become the talk of the town, our friend will condescend to
give the matter the barest amount of attention, whilst he is filling his
pipe or mixing a whisky and soda; but there is not in England that
general attention given to the displays of nature and the philosophy of
those displays, which certainly is a characteristic of the phlegmatic
German. However, things are better than they used to be, and the
forthcoming total eclipse of the Sun of May 28, 1900 (visible as it will
be as a partial eclipse all over Great Britain and Ireland, and as a
total eclipse in countries so near to Great Britain as Spain and
Portugal, to say nothing of the United States), will probably not only
attract a good deal of attention on the part of many millions of
English-speaking people, but may also be expected to induce a
numerically respectable remnant to give their minds and thoughts, with a
certain amount of patient attention, to the Science and Philosophy of
Eclipses.
There are other causes likely to co-operate in bringing this about. It
is true that men’s minds are more enlightened at the end of the 19th
century than they were at the end of the 16th century, and that a trip
to Spain will awaken vastly different thoughts in the year 1900 to those
which would have been awakened, say in the year 1587; but for all that,
a certain amount of superstition still lingers in the world, and total
eclipses as well as comets still give rise to feelings of anxiety and
alarm amongst ill-educated villagers even in so-called civilized
countries. Some amusing illustrations of this will be presented in due
course. For the moment let me content myself by stating the immediate
aim of this little book, and the circumstances which have led to its
being written. What those circumstances are will be understood generally
from what has been said already. Its aim is the unambitious one of
presenting in readable yet sound scientific language a popular account
of eclipses of the Sun and Moon, and (very briefly) of certain kindred
astronomical phenomena which depend upon causes in some degree similar
to those which operate in connection with eclipses. These kindred
phenomena are technically known as “Transits” and “Occultations.”
Putting these two matters entirely aside for the present, we will
confine our attention in the first instance to eclipses; and as eclipses
of the Sun do not stand quite on the same footing as eclipses of the
Moon, we will, after stating the general circumstances of the case, put
the eclipses of the Moon aside for a while.
CHAPTER II.
GENERAL IDEAS.
The primary meaning of the word “Eclipse” (ἔϰλειψις) is a forsaking,
quitting, or disappearance. Hence the covering over of something by
something else, or the immersion of something in something; and these
apparently crude definitions will be found on investigation to represent
precisely the facts of the case.
Inasmuch as the Earth and the Moon are for our present purpose
practically “solid bodies,” each must cast a shadow into space as the
result of being illuminated by the Sun, regarded as a source of light.
What we shall eventually have to consider is: What results arise from
the existence of these shadows according to the circumstances under
which they are viewed? But before reaching this point, some other
preliminary considerations must be dealt with.
The various bodies which together make up the Solar system, that is to
say, in particular, those bodies called the “planets”—some of them
“primary,” others “secondary” (_alias_ “Satellites” or “Moons”)—are
constantly in motion. Consequently, if we imagine a line to be drawn
between any two at any given time, such a line will point in a different
direction at another time, and so it may occasionally happen that three
of these ever-moving bodies will come into one and the same straight
line. Now the consequences of this state of things were admirably well
pointed out nearly half a century ago by a popular writer, who in his
day greatly aided the development of science amongst the masses. “When
one of the extremes of the series of three bodies which thus assume a
common direction is the Sun, the intermediate body deprives the other
extreme body, either wholly or partially, of the illumination which it
habitually receives. When one of the extremes is the Earth, the
intermediate body intercepts, wholly or partially, the other extreme
body from the view of the observers situate at places on the Earth which
are in the common line of direction, and the intermediate body is seen
to pass over the other extreme body as it enters upon or leaves the
common line of direction. The phenomena resulting from such
contingencies of position and direction are variously denominated
_Eclipses_, _Transits_, and _Occultations_, according to the relative
apparent magnitudes of the interposing and obscured bodies, and
according to the circumstances which attend them.”[1]
The Earth moves round the Sun once in every year; the Moon moves round
the Earth once in every lunar month (27 days). I hope everybody
understands those essential facts. Then we must note that the Earth
moves round the Sun in a certain plane (it is nothing for our present
purpose what that plane is). If the Moon as the Earth’s companion moved
round the Earth in the same plane, an eclipse of the Sun would happen
regularly every month when the Moon was in “Conjunction” (“New Moon”),
and also every month at the intermediate period there would be a total
eclipse of the Moon on the occasion of every “Opposition” (or “Full
Moon”). But inasmuch as the Moon’s orbit does not lie in quite the same
plane as the Earth’s, but is inclined thereto at an angle which may be
taken to average about 5⅛°, the actual facts are different; that is to
say, instead of there being in every year about 25 eclipses (solar and
lunar in nearly equal numbers), which there would be if the orbits had
identical planes, there are only a very few eclipses in the year, never,
under the most favourable circumstances, more than 7, and sometimes as
few as 2. Nor are the numbers equally apportioned. In years where there
are 7 eclipses, 5 of them _may_ be of the Sun and 2 of the Moon; where
there are only 2 eclipses, both _must_ be of the Sun. Under no
circumstances can there be in any one year more than 3 eclipses of the
Moon, and in some years there will be none. The reasons for these
diversities are of a technical character, and a full elucidation of them
would not be of interest to the general reader. It may here be added,
parenthetically, that the occasions will be very rare of there being 5
solar eclipses in one year. This last happened in 1823,[2] and will
only happen once again in the next two centuries, namely in 1935. If a
total eclipse of the Sun happens early in January there may be another
in December of the same year, as in 1889 (Jan. 1 and Dec. 22). This will
not happen again till 2057, when there will be total eclipses on Jan. 5
and Dec. 26. There is one very curious fact which may be here
conveniently stated as a bare fact, reserving the explanation of it for
a future page, namely, that eclipses of the Sun and Moon are linked
together in a certain chain or sequence which takes rather more than 18
years to run out when the sequence recurs and recurs _ad infinitum_. In
this 18-year period, which bears the name of the “Saros,” there usually
happen 70 eclipses, of which 41 are of the Sun and 29 of the Moon.
Accordingly, eclipses of the Sun are more numerous than those of the
Moon in the proportion of about 3 to 2, yet at any given place on the
Earth more lunar eclipses are visible than solar eclipses, because the
former when they occur are visible over the whole hemisphere of the
Earth which is turned towards the Moon whilst the area over which a
total eclipse of the Sun is visible is but a belt of the Earth no more
than about 150 to 170 miles wide. Partial eclipses of the Sun, however,
are visible over a very much wider area on either side of the path
traversed by the Moon’s shadow.
[Illustration: FIG. 2.—THEORY OF A TOTAL ECLIPSE OF THE SUN.]
Confining our attention in the first instance to eclipses of the Sun,
the diagrams fig. 2 and fig. 3 will make clear, with very little verbal
description, the essential features of the two principal kinds of
eclipses of the Sun. In these figures S represents the Sun, M the Moon
and E the Earth. They are not, of course, even approximately drawn to
scale either as to the size of the bodies or their relative distances,
but this is a matter of no moment as regards the principles involved. M
being in sunshine receives light on, as it were, the left hand side,
which faces S the Sun. The shadow of the Moon cast into space is, in the
particular case, thrown as regards its tip on to the Earth and is
intercepted by the Earth. Persons at the moment situated on the Earth
within the limits of this shadow will not see any part of the Sun at
all; they will see, in fact, nothing but the Moon as a black disc with
only such light behind and around it as may be reflected back on to the
sky by the illuminated (but to the Earth invisible) hemisphere of the
Moon, or as may proceed from the Sun’s Corona (to be described
presently). The condition of things therefore is that known as a “total”
eclipse of the Sun so far as regards the inhabitants of the narrow strip
of Earth primarily affected.
[Illustration: FIG. 3.—THEORY OF AN ANNULAR ECLIPSE OF THE SUN.]
Fig. 3 represents nearly but not quite the same condition of things.
Here the Earth and the Moon are in those parts of their respective
orbits which put the two bodies at or near the maximum distance
possible from the Sun and from one another. The Moon casts its usual
shadow, but the tip does not actually reach any part of the Earth’s
surface. Or, in other words, to an observer on the Earth the Moon is not
big enough to conceal the whole body of the Sun. The result is this; at
the instant of central coincidence the Moon covers up only the centre of
the Sun, leaving the outer edge all round uncovered.
This outer edge shows as a bright ring of light, and the eclipse is of
the sort known as an “annular” eclipse of the Sun.[3] As the greatest
breadth of the annulus can never exceed 1½ minutes of arc, an annular
eclipse may sometimes, in some part of its track, become almost or quite
total, and _vice versâ_.
[Illustration: FIG. 4.—ANNULAR ECLIPSE OF THE SUN.]
The idea will naturally suggest itself, what exactly does happen to the
inhabitants living outside (on the one side or the other) of the strip
of the Earth where the central line of shadow falls? This depends in
every case on circumstances, but it may be stated generally that the
inhabitants outside the central line but within 1000 to 2000 miles on
either side, will see a larger or smaller part of the Sun concealed by
the Moon’s solid body, simultaneously with the total concealment of the
Sun to the favoured individuals who live, or who for the moment are
located, within the limits of the central zone.
[Illustration: FIG. 5.—PARTIAL ECLIPSE OF THE SUN.]
Now we must advance one stage in our conceptions of the movements of the
Earth and the Moon, so far as regards the bearing of those movements on
the question of eclipses. The Earth moves in a plane which is called the
“Plane of the Ecliptic,” and correspondingly, the Sun has an _apparent_
annual motion in the same plane. The Moon moving in a different plane,
inclined to the first mentioned one to the extent of rather more than
5°, the Moon’s orbit will evidently intersect the ecliptic in two
places. These places of intersection are called “Nodes,” and the line
which may be imagined to join these Nodes is called the “Line of Nodes.”
When the Moon is crossing the ecliptic from the S. to the N. side
thereof, the Moon is said to be passing through its “Ascending Node”
(☊); the converse of this will be the Moon passing back again from the
N. side of the ecliptic to the S. side, which is the “Descending Node”
(☋). Such changes of position, with the terms designating them, apply
not only to the Moon in its movement round the Earth, but to all the
planets and comets circulating round the Sun; and also to satellites
circulating round certain of the planets, but with these matters we have
no concern now.
FOOTNOTES:
[Footnote 1: D. Lardner, _Handbook of Astronomy_, 3rd ed., p. 288.]
[Footnote 2: But not one of them was visible at Greenwich.]
[Footnote 3: Latin _Annulus_, a ring.]
CHAPTER III.
THE “SAROS” AND THE PERIODICITY OF ECLIPSES.
To bring about an eclipse of the Sun, two things must combine: (1) the
Moon must be at or near one of its Nodes; and (2), this must be at a
time when the Moon is also in “Conjunction” with the Sun. Now the Moon
is in Conjunction with the Sun (= “New Moon”) 12 or 13 times in a year,
but the Sun only passes through the Nodes of the Moon’s orbit twice a
year. Hence an eclipse of the Sun does not and cannot occur at every New
Moon, but only occasionally. An _exact_ coincidence of Earth, Moon, and
Sun, in a straight line at a Node is not necessary to ensure an eclipse
of the Sun. So long as the Moon is within about 18½° of its Node, with a
latitude of not more than 1° 34′, an eclipse _may_ take place. If,
however, the distance is less than 15¼° and the latitude less than
1° 23′ an eclipse _must_ take place, though between these limits[4] the
occurrence of an eclipse is uncertain and depends on what are called the
“horizontal parallaxes” and the “apparent semi-diameters” of the two
bodies at the moment of conjunction, in other words, on the nearness or
“far-offness” of the bodies in question. Another complication is
introduced into these matters by reason of the fact that the Nodes of
the Moon’s orbit do not occupy a fixed position, but have an annual
retrograde motion of about 19¼°, in virtue of which a complete
revolution of the Nodes round the ecliptic is accomplished in 18 years
218⅞ days (= 18.5997 years).
The backward movement of the Moon’s Nodes combined with the apparent
motion of the Sun in the ecliptic causes the Moon in its monthly course
round the Earth to complete a revolution with respect to its Nodes in a
less time (27.2 days) than it takes to get back to Conjunction with the
Sun (29.5 days); and a curious consequence, as we shall see directly,
flows from these facts and from one other fact. The other fact is to the
Sun starting coincident with one of the Moon’s Nodes, returns on the
Ecliptic to the same Node in 346.6 days. The first named period of 27.2
days is called the “_Nodical_ Revolution of the Moon” or “Draconic
Month,” the other period of 29.5 days is called the “_Synodical_
Revolution of the Moon.” Now the curious consequence of these figures
being what they are is that 242 Draconic Months, 223 Lunations, and 19
Returns of the Sun to one and the same Node of the Moon’s orbit, are all
accomplished in the same time within 11 hours. Thus (ignoring
refinements of decimals):—
Days Days. Years. Days. Hours.
242 times 27.2 = 6585.36 = 18 10 8½
223 times 29.5 = 6585.32 = 18 10 7¾
19 times 346.6 = 6585.78 = 18 10 18¾
The interpretation to be put upon these coincidences is this: that
supposing Sun and Moon to start together from a Node they would, after
the lapse of 6585 days and a fraction, be found again together very near
the same Node. During the interval there would have been 223 New and
Full Moons. The exact time required for 223 Lunations is such that in
the case supposed the 223rd conjunction of the two bodies would happen a
little before they reached the Node; their distance therefrom would be
28′ of arc. And the final fact is that eclipses recur in almost, though
not quite, the same regular order every 6585⅓ days, or more exactly, 18
years, 10 days, 7 hours, 42 minutes.[5] This is the celebrated Chaldean
“SAROS,” and was used by the ancients (and can still be used by the
moderns in the way of a pastime) for the prediction of eclipses alike of
the Sun and of the Moon.
* * * * *
At the end of a Saros period, starting from any date that may have been
chosen, the Moon will be in the same position with respect to the Sun,
nearly in the same part of the heavens, nearly in the same part of its
orbit, and very nearly indeed at the same distance from its Node as at
the date chosen for the _terminus a quo_ of the Saros. But there are
trifling discrepancies in the case (the difference of about 11 hours
between 223 lunations and 19 returns of the Sun to the Moon’s Node is
one) and these have an appreciable effect in disturbing not so much the
sequence of the eclipses in the next following Saros as their magnitude
and visibility at given places on the Earth’s surface. Hence, a more
accurate succession will be obtained by combining 3 Saros periods,
making 54 years, 31 days; while, best of all, to secure an almost
perfect repetition of a series of eclipses will be a combination of 48
Saroses, making 865 years for the Moon; and of about 70 Saroses, or more
than 1200 years for the Sun.
These considerations are leading us rather too far afield. Let us return
to a more simple condition of things. The practical use of the Saros in
its most elementary conception is somewhat on this wise. Given 18 or 19
old Almanacs ranging, say, from 1880 to 1898, how can we turn to account
the information they afford us in order to obtain from them information
respecting the eclipses which will happen between 1899 and 1917?
Nothing easier. Add 18^y 10^d 7^h 42^m to the middle time of every
eclipse which took place between 1880 and 1898 beginning, say, with the
last of 1879 or the first of 1880, and we shall find what eclipses will
happen in 1898 and 17 following years, as witness by way of example the
following table:—
Error of Saros by
d. h. m. Exact Calculation.
MOON. 1879 Dec. 28 4 26 p.m.
(Mag. 0.17) 18 10 7 42
---------------------------------------------
(Mag. 0.16) 1898 Jan. 8 12 8 a.m. (civil time) +3 m.
d. h. m.
SUN. 1880 Jan. 11 10 48 p.m.
(Total) 18 10 7 42
---------------------------------------------
(Total) 1898 Jan. 22 6 30 a.m. (civil time) -1 h. 7 m.
d. h. m.
MOON. 1880 June 22 1 50 p.m.
(Mag. Total) 18 11 7 42
---------------------------------------------
(Mag. 0.93) 1898 July 3 9 32 p.m. +35 m.
d. h. m.
SUN. 1880 July 7 1 35 p.m.
(Mag. Annular) 18 11 7 42
---------------------------------------------
(Mag. Annular) 1898 July 18 9 17 p.m. +1 h. 10 m.
d. h. m.
SUN. 1880 Dec. 2 3 11 a.m. (civil time).
(Mag. 0.04) 18 11 7 42
---------------------------------------------
(Mag. 0.02) 1898 Dec. 13 10 53 a.m. -1 h. 5 m.
d. h. m.
MOON. 1880 Dec. 16 3 39 p.m.
(Mag. Total) 18 11 7 42
---------------------------------------------
(Mag. Total) 1898 Dec. 27 11 21 p.m. -13 m.
d. h. m.
SUN. 1880 Dec. 31 1 45 p.m.
(Mag. 0.71) 18 11 7 42
---------------------------------------------
(Mag. 0.72) 1899 Jan. 11 9 27 p.m. -1 h. 11 m.
There having been 5 recurrences of Feb. 29 between Dec. 1879 and Jan.
1899, 5 leap years having intervened, we have to add an extra day to the
Saros period in the later part of the above Table.[6]
Let us make another start and see what we can learn from the eclipses,
say, of 1883.
Error of Saros by
Exact Calculation.
h. m.
MOON 1883 April 22 11 39 a.m.
(Mag. 0.8) 18 11 7 42
--------------------------------------------
(Mag. Penumbral) 1901 May 3 7 21 p.m. +51 m.
h. m.
SUN 1883 May 6 9 45 p.m. Visible, Philippines.
(Mag. Total) 18 11 7 42
--------------------------------------------
(Mag. Total) 1901 May 18 5 27 a.m. (civil time). -2 m.
h. m.
MOON 1883 Oct. 16 6 54 a.m. Visible, California.
(Mag. 0.28) 18 11 7 42
--------------------------------------------
(Mag. 0.23) 1901 Oct. 27 2 36 p.m. -39 m.
h. m.
SUN 1883 Oct. 30 11 37 p.m. Visible, N. Japan.
(Mag. Annular) 18 11 7 42
--------------------------------------------
(Mag. Annular) 1901 Nov. 11 7 19 a.m. (civil time) +1 m.
The foregoing does not by any means exhaust all that can be said
respecting the Saros even on the popular side.
If the Saros comprised an exact number of days, each eclipse of a second
Saros series would be visible in the same regions of the Earth as the
corresponding eclipse in the previous series. But since there is a
surplus fraction of nearly one-third of a day, each subsequent eclipse
will be visible in another region of the Earth, which will be roughly a
third of the Earth’s circumference in longitude backwards (_i.e._ about
120° to the W.), because the Earth itself will be turned on its axis
one-third forwards.
After what has been said as to the Saros and its use it might be
supposed that a correct list of eclipses for 18.03 years would suffice
for all ordinary purposes of eclipse prediction, and that the sequence
of eclipses at any future time might be ascertained by adding to some
one eclipse which had already happened so many Saros periods as might
embrace the years future whose eclipses it was desired to study. This
would be true in a sense, but would not be literally and effectively
true, because corresponding eclipses do not recur exactly under the same
conditions, for there are small residual discrepancies in the times and
circumstances affecting the real movements of the Earth and Moon and the
apparent movement of the Sun which, in the lapse of years and centuries,
accumulate sufficiently to dislocate what otherwise would be exact
coincidences. Thus an eclipse of the Moon which in A.D. 565 was of 6
digits[7] was in 583 of 7 digits, and in 601 nearly 8. In 908 the
eclipse became total, and remained so for about twelve periods, or until
1088. This eclipse continued to diminish until the beginning of the 15th
century, when it disappeared in 1413. Let us take now the life of an
eclipse of the Sun. One appeared at the North Pole in June A.D. 1295,
and showed itself more and more towards the S. at each subsequent
period. On August 27, 1367, it made its first appearance in the North of
Europe; in 1439 it was visible all over Europe; in 1601, being its 19th
appearance, it was central and annular in England; on May 5, 1818, it
was visible in London, and again on May 15, 1836. Its three next
appearances were on May 26, 1854, June 6, 1872, and June 17, 1890. At
its 39th appearance, on August 10, 1980, the Moon’s shadow will have
passed the equator, and as the eclipse will take place nearly at
midnight (Greenwich M.T.), the phenomenon will be invisible in Europe,
Africa, and Asia. At every succeeding period the central line of the
eclipse will lie more and more to the S., until finally, on September
30, 2665, which will be its 78th appearance, it will vanish at the South
Pole.[8]
The operation of the Saros effects which have been specified above, may
be noticed in some of the groups of eclipses which have been much in
evidence (as will appear from a subsequent chapter), during the second
half of the 19th century. The following are two noteworthy Saros groups
of Solar eclipses:—
1842 July 8. | 1850 Aug. 7.
1860 " 18. | 1868 " 17.
1878 " 29. | 1886 " 29.
1896 Aug. 9. | 1904 Sept. 9.
If the curious reader will trace, by means of the _Nautical Almanac_
(or some other Almanac which deals with eclipses in adequate detail),
the geographical distribution of the foregoing eclipses on the Earth’s
surface, he will see that they fulfil the statement made on p. 24
(_ante_), that a Saros eclipse when it reappears, does so in regions of
the Earth averaging 120° of longitude to the W. of those in which it
had, on the last preceding occasion, been seen; and also that it
gradually works northwards or southwards.
But a given Saros eclipse in its successive reappearances undergoes
other transformations besides that of Terrestrial longitude. These are
well set forth by Professor Newcomb[9]:—
“Since every successive recurrence of such an eclipse throws the
conjunction 28′ further toward the W. of the node, the conjunction must,
in process of time, take place so far back from the node that no eclipse
will occur, and the series will end. For the same reason there must be a
commencement to the series, the first eclipse being E. of the node. A
new eclipse thus entering will at first be a very small one, but will be
larger at every recurrence in each Saros. If it is an eclipse of the
Moon, it will be total from its 13th until its 36th recurrence. There
will be then about 13 partial eclipses, each of which will be smaller
than the last, when they will fail entirely, the conjunction taking
place so far from the node that the Moon does not touch the Earth’s
shadow. The whole interval of time over which a series of lunar eclipses
thus extend will be about 48 periods, or 865 years. When a series of
solar eclipses begins, the penumbra of the first will just graze the
earth not far from one of the poles. There will then be, on the average,
11 or 12 partial eclipses of the Sun, each larger than the preceding
one, occurring at regular intervals of one Saros. Then the central line,
whether it be that of a total or annular eclipse, will begin to touch
the Earth, and we shall have a series of 40 or 50 central eclipses. The
central line will strike near one pole in the first part of the series;
in the equatorial regions about the middle of the series, and will leave
the Earth by the other pole at the end. Ten or twelve partial eclipses
will follow, and this particular series will cease.”
These facts deserve to be expanded a little.
We have seen that all eclipses may be grouped in a series, and that 18
years or thereabouts is the duration of each series, or Saros cycle. But
these cycles are themselves subject to cycles, so that the Saros itself
passes through a cycle of about 64 Saroses before the conditions under
which any given start was made, come quite round again. Sixty-four times
18 make 1152, so that the duration of a Solar eclipse Great Cycle may be
taken at about 1150 years. The progression of such a series across the
face of the Earth is thus described by Mrs. Todd, who gives a very clear
account of the matter:—
“The advent of a slight partial eclipse near either pole of the Earth
will herald the beginning of the new series. At each succeeding return
conformably to the Saros, the partial eclipse will move a little further
towards the opposite pole, its magnitude gradually increasing for about
200 years, but during all this time only the lunar penumbra will impinge
upon the Earth. But when the true shadow begins to touch, the
obscuration will have become annular or total near the pole where it
first appeared. The eclipse has now acquired a track, which will cross
the Earth slightly farther from that pole every time it returns, for
about 750 years. At the conclusion of this interval, the shadow path
will have reached the opposite pole; the eclipse will then become
partial again, and continue to grow smaller and smaller for about 200
years additional. The series then ceases to exist, its entire duration
having been about 1150 years. The series of “great eclipses” of which
two occurred in 1865 and 1883, while others will happen in 1901, 1919,
1937, 1955, and 1973, affords an excellent instance of the northward
progression of eclipse tracks; and another series, with totality nearly
as great (1850, 1868, 1886, 1904, and 1922), is progressing slowly
southwards.”
The word “Digit,” formerly used in connection with eclipses, requires
some explanation. The origin of the word is obvious enough, coming as it
does from the Latin word _Digitus_, a finger. But as human beings have
only eight fingers and two thumbs it is by no means clear how the word
came to be used for twelfths of the disc of the Sun or Moon instead of
tenths. However, such was the case; and when a 16th-century astronomer
spoke of an eclipse of six digits, he meant that one-half of the
luminary in question, be it Sun or Moon, was covered. The earliest use
of the word “Digit” in this connection was to refer to the twelfth part
of the visible _surface_ of the Sun or Moon; but before the word went
out of use, it came to be applied to twelfths of the visible _diameter_
of the disc of the Sun or Moon, which was much more convenient. However,
the word is now almost obsolete in both senses, and partial eclipses,
alike of the Sun and of the Moon, are defined in decimal parts of the
diameter of the luminary—tenths or hundredths according to the amount of
precision which is aimed at. Where an eclipse of the Moon is described
as being of more than 12 Digits or more than 1.0 (= 1 diameter) it is to
be understood that the eclipse will be (or was) not only total, but that
the Moon will be (or was) immersed in the Earth’s shadow with a more or
less considerable extent of shadow encompassing it.
There are some further matters which require to be mentioned connected
with the periodicity of eclipses. To use a phrase which is often
employed, there is such a thing as an “Eclipse Season,” and what this is
can only be adequately comprehended by looking through a catalogue of
eclipses for a number of years arranged in a tabular form, and by
collating the months or groups of months in which batches of eclipses
occur. This is not an obvious matter to the casual purchaser of an
almanac, who, feeling just a slight interest in the eclipses of a coming
new year, dips into his new purchase to see what those eclipses will be.
A haphazard glance at the almanacs of even two or three successive years
will probably fail to bring home to him the idea that each year has its
own eclipse season in which eclipses may occur, and that eclipses are
not to be looked for save at two special epochs, which last about a
month each, and which are separated from one another and from the
eclipse seasons of the previous and of the following years by intervals
of about six months, within a few days more or less. Such, however, is
the case. A little thought will soon make it clear why such should be
the case. We have already seen that the Moon’s orbit, like that of every
other planetary member of the Solar System, has two crossing places with
respect to the ecliptic which are called “Nodes.” We know also that the
apparent motion of the Sun causes that body to traverse the whole of the
ecliptic in the course of the year. The conjoint result of all this is
that the Moon passes through a Node twice in every lunar month of 27
days, and the Sun passes (apparently) through a Node twice in every
year. The first ultimate result of these facts is that eclipses can only
take place at or near the nodal passages of the Moon and the Sun, and
that as the Sun’s nodal passages are separated by six months in every
case the average interval between each set of eclipses, if there is more
than one, must in all cases be six months, more or less by a few days,
dependent upon the latitude and longitude of the Moon at or about the
time of its Conjunction or Opposition under the circumstances already
detailed. If the logic of this commends itself to the reader’s mind, he
will see at once why eclipses or groups of eclipses must be separated by
intervals of about half an ordinary year. Hence it comes about that,
taking one year with another, it may be said that we shall always have a
couple of principal eclipses with an interval of half a year (say 183
days) between each; and that on either side of these dominant eclipses
there will, or may be, a fortnight before or a fortnight after, two
other pairs of eclipses with, in occasional years, one extra thrown in.
It is in this way that we obtain what it has already been said
dogmatically that we do obtain; namely, always in one year two eclipses,
which must be both of the Sun, or any number of eclipses up to seven,
which number will be unequally allotted to the Sun or to the Moon
according to circumstances.
Though it is roughly correct to say that the two eclipse seasons of
every year run to about a month each, in length, yet it may be desirable
to be a little more precise, and to say that the limits of time for
solar eclipses cover 36 days (namely 18 days before and 18 days after
the Sun’s nodal passages); whilst in the case of the Moon, the limits
are the lesser interval of 23 days, being 11½ on either side of the
Moon’s nodal passages.
We have already seen[10] that the Moon’s nodes are perpetually
undergoing a change of place. Were it not so, eclipses of the Sun and
Moon would always happen year after year in the same pair of months for
us on the Earth. But the operative effect of the shifting of the nodes
is to displace backwards the eclipse seasons by about 20 days. For
instance in 1899 the eclipse seasons fall in June and December. The
middle of the eclipse seasons for the next succeeding 20 or 30 years
will be found by taking the dates of June 8 and December 2, 1899, and
working the months backwards by the amount of 19⅔ days for each
succeeding year. Thus the eclipse seasons in 1900 will fall in the
months of May and November; accordingly amongst the eclipses of that
year we shall find eclipses on May 28, June 13, and November 22.
Perhaps it would tend to the more complete elucidation of the facts
stated in the last half dozen pages, if I were to set out in a tabular
form all the eclipses of a succession, say of half a Saros or 9 years,
and thus exhibit by an appeal to the eye directly the grouping of
eclipse seasons the principles of which I have been endeavouring to
define and explain in words.
Approximate
Mid-interval.
1894. March 21. ☾ } March 29. *
April 6. ☉ }
Sept. 15. ☾ } Sept. 22. **
Sept. 29. ☉ }
1895. March 11. ☾ } March 18. *
March 26. ☉ }
Aug. 20. ☉ }
Sept. 4. ☾ } Sept. 4. **
Sept. 18. ☉ }
1896. Feb. 13. ☉ } Feb. 20. *
Feb. 28. ☾ }
Aug. 9. ☉ } Aug. 16. **
Aug. 23. ☾ }
1897. Feb. 1. ☉ Feb. 1. *
July 29. ☉ July 29. **
1898. Jan. 7. ☾ } Jan. 14. *
Jan. 22. ☉ }
July 3. ☾ } July. 10. **
July 18. ☉ }
Dec. 13. ☉ }
Dec. 27. ☾ } Dec. 27. *
1899. Jan. 11. ☉ }
June 8. ☉ } June 15. **
June 23. ☾ }
Dec. 2. ☉ } Dec. 9. *
Dec. 16. ☾ }
1900. May 28. ☉ } June 5. **
June 13. ☾ }
Nov. 22. ☉ Nov. 22. *
1901. May 3. ☾ } May 10. **
May 18. ☉ }
Oct. 27. ☾ } Nov. 3. *
Nov. 11. ☉ }
1902. April 8. ☉ }
April 22. ☾ } April 22. **
May 7. ☉ }
Oct. 17. ☾ } Oct. 24. *
Oct. 31. ☉ }
The Epochs in the last column which are marked with stars (*) or (**) as
the case may be, represent corresponding nodes so that from any one
single-star date to the next nearest single-star date means an interval
of one year less (on an average) the 19⅔ days spoken of on p. 32
(_ante_). A glance at each successive pair of dates will quickly
disclose the periodical retrogradation of the eclipse epochs.
FOOTNOTES:
[Footnote 4: These limits are slightly different in the case of
eclipses of the Moon. (See p. 190, _post_.)]
[Footnote 5: This assumes that 5 of these years are leap years.]
[Footnote 6: If there are 5 leap years in the 18, the odd days will
be 10; if 4 they will be 11; if only 3 leap years (as from 1797 to
1815 and 1897 to 1915), the odd days to be added will be 12.]
[Footnote 7: See p. 28 (_post_) for an explanation of this word.]
[Footnote 8: In Mrs. D. P. Todd’s interesting little book, _Total
Eclipses of the Sun_ (Boston, U.S., 1894), which will be several
times referred to in this work, two maps will be found, which will
help to illustrate the successive northerly or southerly progress of
a series of Solar eclipses, during centuries.]
[Footnote 9: In his and Professor Holden’s _Astronomy for Schools
and Colleges_, p. 184.]
[Footnote 10: See p. 19 (_ante_).]
CHAPTER IV.
MISCELLANEOUS THEORETICAL MATTERS CONNECTED
WITH ECLIPSES OF THE SUN (CHIEFLY).
One or two miscellaneous matters respecting eclipses of the Sun
(chiefly) will be dealt with in this chapter. It is not easy to explain
or define in words the circumstances which control the duration of a
Solar eclipse, whereas in the case of a lunar eclipse the obscuration is
the same in degree at all parts of the Earth where the Moon is visible.
In the case of a Solar eclipse it may be total, perhaps, in Africa, may
be of six digits only in Spain, and of two only in England. Under the
most favourable circumstances the breadth of the track of totality
across the Earth cannot be more than 170 miles, and it may be anything
less than that down to zero where the eclipse will cease to be total at
all, and will become annular. The question whether a given eclipse shall
exhibit itself on its central line as a total or an annular one depends,
as has been already explained, on the varying distances of the Earth and
the Moon from the Sun in different parts of their respective orbits.
Hence it follows that not only may an eclipse show itself for several
Saros appearances as total and afterwards become annular, and _vice
versâ_, but on rare occasions one and the same eclipse may be annular in
one part of its track across the Earth and total in another part, a
short time earlier or later. This last-named condition might arise
because the Moon’s distance from the Earth or the Sun had varied
sufficiently during the progress of the eclipse to bring about such a
result; or because the shadow just reaching the Earth and no more the
eclipse would be total only for the moment when a view perpendicular
upwards could be had of it, and would be annular for the minutes
preceding and the minutes following the perpendicular glimpse obtained
by observers actually on the central line. The eclipse of December 12,
1890, was an instance of this.
If the paths of several central eclipses of the Sun are compared by
placing side by side a series of charts, such as those given in the
_Nautical Almanac_ or in Oppolzer’s _Canon_, it will be noticed that the
direction of the central line varies with the season of the year. In the
month of March the line runs from S.W. to N.E., and in September from
N.W. to S.E. In June the line is a curve, going first to the N.E. and
then to the S.E. In December the state of things is reversed, the curve
going first to the S.E. and then to the N.E. At all places within about
2000 miles of the central line the eclipse will be visible, and the
nearer a place is to the central line, so much the larger will be the
portion of the Sun’s disc concealed from observers there by the Moon.
If the central line runs but a little to the N. of the Equator in Winter
or of 25° of N. latitude in Summer, the eclipse will be visible all over
the Northern Hemisphere, and the converse will apply to the Southern
Hemisphere. It is something like a general rule in the case of total and
annular eclipses, though subject to many modifications, that places
within 200-250 miles of the central line will have partial eclipse of 11
digits; from thence to 500 miles of 10 digits, and so on, diminishing
something like 1 digit for every 250 miles, so that at 2000 miles, or
rather more, the Sun will be only to a very slight extent eclipsed, or
will escape eclipse altogether.
The diameter of the Sun being 866,000 miles and the Moon being only 2160
miles or 1/400th how comes it to be possible that such a tiny object
should be capable of concealing a globe 400 times bigger than itself?
The answer is—Distance. The increased distance does it. The Moon at its
normal distance from the Earth of 237,000 miles could only conceal by
eclipse a body of its own size or smaller, but the Sun being 93,000,000
miles away, or 392 times the distance of the Moon, the fraction 1/392
representing the main distance of the Moon, more than wipes out the
fraction 1/400 which represents our satellite’s smaller size.
During a total eclipse of the Sun, the Moon’s shadow travels across the
Earth at a prodigious pace—1830 miles an hour; 30½ miles a minute; or
rather more than a ½ mile a second. This great velocity is at once a
clue to the fact that the total phase during an eclipse of the Sun
lasts for so brief a time as a few minutes; and also to the fact that
the shadow comes and goes almost without being seen unless a very sharp
watch is kept for it. Indeed, it is only observers posted on high ground
with some miles of open low ground spread out under their eyes who have
much chance of detecting the shadow come up, go over them, and pass
forwards.
Places at or near the Earth’s equator enjoy the best opportunities for
seeing total eclipses of the Sun, because whilst the Moon’s shadow
travels eastwards along the Earth’s surface at something like 2000 miles
an hour, an observer at the equator is carried in the same direction by
virtue of the Earth’s axial rotation at the rate of 1040 miles an hour.
But the speed imparted to an observer as the result of the Earth’s axial
rotation diminishes from the equator towards the poles where it is
_nil_, so that the nearer he is to a pole the slower he goes, and
therefore the sooner will the Moon’s shadow overtake and pass him, and
the less the time at his disposal for seeing the Sun hidden by the Moon.
It was calculated by Du Sèjour that the greatest possible duration of
the total phase of a Solar eclipse at the equator would be 7^m 58^s, and
for the latitude of Paris 6^m 10^s. In the case of an annular eclipse
the figures would be 12^m 24^s for the equator, and 9^m 56^s for the
latitude of Paris. These figures contemplate a combination of all the
most favourable circumstances possible; as a matter of fact, I believe
that the greatest length of total phase which has been actually known
was 6½^m and that was in the case of the eclipse of August 29, 1886. It
was in the open Atlantic that this duration occurred, but it was not
observed. The maximum observed obscuration during this eclipse was no
more than 4^m.
Though total eclipses of the Sun happen with tolerable frequency so far
as regards the Earth as a whole, yet they are exceedingly rare at any
given place. Take London, for instance. From the calculations of Hind,
confirmed by Maguire,[11] it may be considered as an established fact
that there was no total eclipse visible at London between A.D. 878 and
1715, an interval of 837 years. The next one visible at London, though
uncertain, is also a very long way off. There will be a total eclipse on
August 11, 1999, which will come as near to London as the Isle of Wight,
but Hind, writing in 1871, said that he doubted whether there would be
any other total eclipse “visible _in England_ for 250 years[12] from the
present time.” Maguire states that the Sun has been eclipsed, besides
twice at London, also twice at Dublin, and no fewer than five times at
Edinburgh during the 846 years examined by him. In fact that every part
of the British Isles has seen a total eclipse at some time or other
between A.D. 878 and 1724 except a small tract of country at Dingle, on
the West coast of Ireland. The longest totality was on June 15, 885,
namely, 4^m 55^s, and the shortest in July 16, 1330, namely, 0^m 56^s.
Contrast with this the obscure island of Blanquilla, off the northern
coast of Venezuela. The inhabitants of that island not long ago had the
choice of two total eclipses within three and a half years, namely,
August 29, 1886, and December 22, 1889; whilst Yellowstone, U.S., had
two in twelve years (July 29, 1878, and January 1, 1889).
Counting from first to last, Du Sèjour found that at the equator an
eclipse of the Sun might last 4^h 29^m, and at the latitude of Paris 3^h
26^m. These intervals, of course, cover all the subordinate phases. The
total phase which alone (with perhaps a couple of minutes added) is
productive of spectacular effects, and interesting scientific results is
a mere matter of minutes which may be as few as one (or less), or only
as many as 6 or 8.
As a rule, a summer eclipse will last longer than a winter one, because
in summer the Earth (and the Moon with it), being at its maximum
distance from the Sun, the Sun will be at its minimum apparent size, and
therefore the Moon will be able to conceal it the longer.
FOOTNOTES:
[Footnote 11: _Month. Not._, _R.A.S._, vol. xlv., p. 400. June
1885.]
[Footnote 12: Johnson makes the eclipse of June 14, 2151, to be
“nearly, if not quite, total at London.” Possibly it was this
eclipse which Hind had in his thoughts when he wrote in the _Times_
(July 28, 1871) the passage quoted above.]
CHAPTER V.
WHAT IS OBSERVED DURING THE EARLIER STAGES
OF AN ECLIPSE OF THE SUN.
The information to be given in this and the next following chapters will
almost exclusively concern total and annular eclipses of the Sun, for,
in real truth, there is practically only one thing to think about during
a partial eclipse of the Sun. This is, to watch when the Moon’s black
body comes on to the Sun and goes off again, for there are no subsidiary
phenomena, either interesting or uninteresting, unless, indeed, the
eclipse should be nearly total. The progress of astronomical science in
regard to eclipses has been so extensive and remarkable of late years
that, unless the various points for consideration are kept together
under well-defined heads, it will be almost impossible either for a
writer or a reader to do full justice to the subject. Having regard to
the fact that the original conception of this volume was that it should
serve as a forerunner to the total solar eclipse of May 28, 1900 (and
through that to other total eclipses), from a popular rather than from a
technical standpoint, I think it will be best to mention one by one the
principal features which spectators should look out for, and to do so as
nearly as may be in the order which Nature itself will observe when the
time comes.
Of course the commencement of an eclipse, which is virtually the moment
when the encroachment on the circular outline of the Sun by the Moon
begins, or can be seen, though interesting as a proof that the
astronomer’s prophecy is about to be fulfilled, is not a matter of any
special importance, even in a popular sense, much less in a scientific
sense. As a rule, the total phase does not become imminent, so to speak,
until a whole hour and more has elapsed since the first contact; and
that hour will be employed by the scientific observer, less in looking
at the Sun than in looking at his instruments and apparatus. He will do
this for the purpose of making quite sure that everything will be ready
for the full utilisation to the utmost extent of the precious seconds of
time into which all his delicate observations have to be squeezed during
the total phase.
With these preliminary observations I shall proceed now to break up the
remainder of what I have to say respecting total eclipses into what
suggest themselves as convenient sectional heads.
THE MOON’S SHADOW AND THE DARKNESS IT CAUSES.
In awaiting the darkness which is expected to manifest itself an
unthinking and inexperienced observer is apt to look out for the coming
obscurity, as he looks out for night-fall half an hour or more after
sunset and during the evening twilight. The darkness of an eclipse is
all this and something more. It is something more in two senses; for the
interval of time between the commencement of an eclipse and totality is
different in duration and different in quality, so to speak, from the
diminution of daylight on the Earth which ensues as the twilight of
evening runs its course. Speaking roughly, sunset may be described as an
almost instantaneous loss of full sunlight; and the gradual loss of
daylight is noticeable even at such short intervals as from one five
minutes to another. This is by no means the case previous to a total
eclipse of the Sun. When that is about to occur, the reduction of the
effective sunlight is far more gradual. For instance, half an hour after
an eclipse has commenced more than half the Sun’s disc will still be
imparting light to the Earth: but half an hour after sunset the
deficiency of daylight will be very much more marked and, if no
artificial light is at hand, very much more inconvenient.
If there should be within easy reach of the observer’s post a bushy
tree, such for instance as an elm, 30 ft. or 40 ft. high, and spreading
out sufficiently for him to place himself under it in a straight line
with the Sun, and with a nice smooth surface of ground for the sun’s
rays to fall on, he will see a multitude of images of the Sun thrown
upon the ground.
Until the eclipse has commenced these images will be tiny circles
overlapping one another, and of course each of these circles means so
many images of the Sun. These images indeed can be seen on any fine day,
and the circles increase in size in proportion to the height of the
foliage above the ground, being something like 1 inch for every 10 feet.
It may be remarked, by the way, that the images are circles, because the
Sun is a source of light having a circular outline, and is not a point
of light like a star. If it were, the outline of the foliage would be
reproduced on the ground leaf for leaf. It follows naturally from all
this that when in consequence of there being an eclipse in progress the
shape of the Sun’s contour gradually changes, so will the shape of the
Solar images on the ground change, becoming eventually so many
crescents. Moreover, the horns of the crescent-shaped images will be in
the reverse direction to the horns of the actual crescent of the Sun at
the moment, the rays of the Sun crossing as they pass through the
foliage, just as if each interstice were a lens.
Supposing there are some spots on the Sun at a time when an eclipse is
in progress the Moon’s passage over these spots may as well be noticed.
In bygone years some amount of attention was devoted to this matter with
the view of ascertaining whether any alteration took place in the
appearance of the spots; distortion, for instance, such as might be
produced by the intervention of a lunar atmosphere. No such distortion
was ever noticed, and observations with this idea in view may be said to
possess now only an academic interest, for it may be regarded as a
well-established fact that the Moon has no atmosphere.
During the passage of the Moon over Sun-spots an opportunity is afforded
of comparing the blackness, or perhaps we should rather say, the
intensity of the shade of a Sun-spot with the blackness of the Moon’s
disc. Testimony herein is unanimous that the blackness of the Moon
during the stages of partial eclipse is intense compared with the
darkest parts of a Sun-spot; and this, be it remembered, in spite of the
fact that during the partial phase the atmosphere between the observer
and the Sun is brilliantly illuminated, whilst the Moon itself, being
exposed to Earth-shine, is by no means absolutely devoid of all
illumination.
When the Moon is passing across the Sun there have often been noticed
along the limb of the Moon fringes of colour, and dark and bright bands.
This might not necessarily be a real appearance for it is conceivable
that such traces of colour might be due to the telescopes employed not
having been truly achromatic, that is, not sufficiently corrected for
colour; but making every allowance for this possible source of mistake
there yet remains proof that the colour which has often been seen has
been real.
As to whether the Moon’s limb can be seen during a partial eclipse, or
during the partial phase of what is to be a total eclipse, the evidence
is somewhat conflicting. There is no doubt that when the totality is
close at hand the Moon’s limb can be seen projected on the Corona
(presently to be described); but the question is, whether the far-off
limb of the Moon can be detected in the open sky whilst something like
full daylight still prevails on the Earth. Undoubtedly the preponderance
of evidence is against the visibility of the Moon as a whole, under such
circumstances; but there is nevertheless some testimony to the contrary.
A French observer, E. Liais, said that three photographic plates of the
eclipse of 1858 seen in S. America all showed the outer limb of the
Moon with more or less distinctness. This testimony, be it noted, is
photographic and not visual; and on the whole it seems safest to say
that there is very small probability of the Moon as a whole ever being
seen under the circumstances in question.
What has just been said concerns the visibility of the Moon during quite
the early, or on the other hand during quite the late, stages of a total
eclipse. Immediately before or after totality the visibility of the
whole contour of the Moon is a certain fact; and the only point upon
which there is a difference of opinion is as to what are the time-limits
beyond which the Moon must not be expected to be seen. The various
records are exceedingly contradictory: perhaps the utmost that can be
said is that the whole Moon must not be expected to be visible till
about 20 minutes before totality, or for more than 5 minutes after
totality—but it must be admitted that these figures are very uncertain
in regard to any particular eclipse.
It has been sometimes noticed when the crescent of the Sun had become
comparatively small, say that the Sun was about ⅞ths covered, that the
uncovered portion exhibited evident colour which has been variously
described as “violet,” “brick-red,” “reddish,” “pink,” “orange,”
“yellowish.” The observations on this point are not very numerous and,
as will appear from the statement just made, are not very consistent;
still it seems safe to assume that a hue, more or less reddish, does
often pervade the uncovered portion of a partially-eclipsed Sun.
The remark just made as regards the Sun seems to have some application
to the Moon. There are a certain number of instances on record that what
is commonly spoken of as the black body of the Moon does, under certain
circumstances, display traces of red which has been variously spoken of
as “crimson,” “dull coppery,” “reddish-brownish” and “dull glowing
coal.”
SHADOW BANDS.
Let us suppose that we have a chance of observing a total eclipse of the
Sun; have completed all our preliminary preparations; have taken note of
everything which needs to be noted or suggests itself for that purpose
up till nearly the grand climax; and that the clock tells us that we are
within, say, five minutes of totality. Somewhere about this time perhaps
we shall be able to detect, dancing across the landscape, singular wavy
lines of light and shade. These are the “Shadow Bands,” as they are
called. The phrase is curiously inexplicit, but seemingly cannot be
improved upon at present because the philosophy of these
appearances—their origin and the laws which regulate their
visibility—are unknown, perhaps because amid the multitude of other
things to think about sufficient attention has hitherto not been paid to
the study of them. These shadow bands are most striking if a high
plastered wall, such as the front of a stone or stuccoed house, is in
their track as a screen to receive them. The shadow bands seem to vary
both in breadth and distance apart at different eclipses, and also in
the speed with which they pass along. Though, as already stated, little
is known of their origin yet they may be conceived to be due to
irregularities in the atmospheric refraction of the slender beam of
light coming from the waning or the waxing crescent of the Sun, for be
it understood they may be visible after totality as well as before it.
It is to be remarked that they have never been photographed.
[Illustration: FIG. 6.—SHADOW BANDS.]
In addition to the shadow bands there are instances on record of the
limbs of the Sun’s crescent appearing to undulate violently on the
approach of totality. These undulations were noticed by Airy in 1842
about 6 minutes before totality. Blake, in America in 1869, observed the
same phenomenon 8 minutes before totality. In other cases the interval
would seem to have been very much shorter—a mere matter of seconds. A
very singular observation was made in 1858 by Mr. J. D. Smith at Laycock
Abbey, Wiltshire, on the occasion of the annular eclipse of that year.
He says[13]:—“Both my brother and myself were distinctly impressed with
the conviction that the withdrawal of light was not continuous, but by
pulsations, or, as it were, waves of obscuration, the darkness
increasing by strokes which sensibly smote the eye, and were repeated
distinctly some five or seven times after we had remarked the phenomenon
and before the time of greatest obscuration. This did not occur on the
return of light, which came back continuously and without shock or
break.” Rümker mentions that though this phenomenon was very apparent to
the naked eye it was not visible in the telescope.
Faint rays or brushes of light sometimes seem to spring from the
diminishing crescent of the Sun. These rays generally are very transient
and not very conspicuous, and perhaps must be distinguished as regards
both their appearance and their origin from the more striking rays
which are usually seen a few minutes before or after totality, and which
are generally associated with, or even deemed to belong to, the Corona.
Fig. 7 represents these rays as seen in Spain on July 18, 1860, some
minutes after totality. They are described as having been well defined,
but at some moments more marked than at others, and though well-defined
yet constantly varying. Radiations of light more or less of the
character just described may probably be regarded as a standing feature
of every total eclipse.
[Illustration: FIG. 7.—RAYS OF LIGHT SEEN NEAR THE TIME OF TOTALITY.]
THE APPROACH OF TOTALITY.
The next thing to think about and to look out for is the approach of the
Moon’s shadow. I have mentioned this already,[14] and also the
appalling velocity with which it seems to approach. By this time the
coming darkness, which characterises every total phase, will have
reached an advanced stage of development. The darkness begins to be
felt. The events which manifest themselves at this juncture on the Earth
(rather than in the sky around the Sun) are so graphically described by
the American writer whom I have already quoted, and who writes,
moreover, from personal experience, that I cannot do better than
transfer her striking account to my pages.[15] “Then, with frightful
velocity, the actual shadow of the Moon is often seen approaching, a
tangible darkness advancing almost like a wall, swift as imagination,
silent as doom. The immensity of nature never comes quite so near as
then, and strong must be the nerves not to quiver as this blue-black
shadow rushes upon the spectator with incredible speed. A vast, palpable
presence seems overwhelming the world. The blue sky changes to gray or
dull purple, speedily becoming more dusky, and a death-like trance
seizes upon everything earthly. Birds, with terrified cries, fly
bewildered for a moment, and then silently seek their night-quarters.
Bats emerge stealthily. Sensitive flowers, the scarlet pimpernel, the
African mimosa, close their delicate petals, and a sense of hushed
expectancy deepens with the darkness. An assembled crowd is awed into
absolute silence almost invariably. Trivial chatter and senseless joking
cease. Sometimes the shadow engulfs the observer smoothly, sometimes
apparently with jerks; but all the world might well be dead and cold and
turned to ashes. Often the very air seems to hold its breath for
sympathy; at other times a lull suddenly awakens into a strange wind,
blowing with unnatural effect. Then out upon the darkness, gruesome but
sublime, flashes the glory of the incomparable corona, a silvery, soft,
unearthly light, with radiant streamers, stretching at times millions of
uncomprehended miles into space, while the rosy, flaming protuberances
skirt the black rim of the Moon in ethereal splendour. It becomes
curiously cold, dew frequently forms, and the chill is perhaps mental as
well as physical. Suddenly, instantaneous as a lightning flash, an arrow
of actual sunlight strikes the landscape, and Earth comes to life again,
while corona and protuberances melt into the returning brilliance, and
occasionally the receding lunar shadow is glimpsed as it flies away with
the tremendous speed of its approach.”
In connection with the approach of the Moon’s shadow, it is to be noted
that at totality the heavens appear in a certain sense to descend upon
the Earth. If an observer is looking upwards towards the zenith over his
head, he will see the clouds appear to drop towards the Earth, and the
surrounding gloom seems also to have the effect of vitiating one’s
estimate of distances. To an observer upon a high hill, a plain below
him appears to become more distant. Although what has been called the
descent of the clouds (that is to say their appearance of growing
proximity) is most manifest immediately before the totality, yet a sense
of growing nearness may sometimes be noticed a very considerable time
before the total phase is reached.
Whilst on the subject of clouds, it may be mentioned that although there
is in the vault of heaven generally during the total phase an
appreciable sensation of black darkness, more or less absolute, that is
to say, either blackish or greyish, yet in certain regions of the sky,
(generally in the direction of the horizon) the clouds, when there are
any, often exhibit colours in strata, orange hue below and red above,
with indigo or grey or black higher up still, right away to the Sun’s
place. The cause of these differences is to be found in the fact that
the lower part of the atmosphere within the area of the Moon’s shadow
is, under the circumstances in question, illuminated by light which
having passed through many miles of atmosphere near to the Earth’s
surface, has lost much from the violet end of its spectrum, leaving an
undue proportion of the red end.
On certain occasions iridescent or rainbow-tinted clouds may be seen in
the vicinity of the Sun, either before, or during, or after totality,
depending on circumstances unknown. Such clouds have been observed at
all these three stages of a total eclipse. The effects of course are
atmospheric, and have no physical connection with either Sun or Moon.
THE DARKNESS OF TOTALITY.
With respect to the general darkness which prevails during totality,
great discrepancies appear in the accounts, not only as between
different eclipses, but in respect of the same eclipse observed by
different people at different places. Perhaps the commonest test applied
by most observers is that of the facility or difficulty of reading the
faces of chronometers or watches. Sometimes this is done readily, at
other times with difficulty. In India in 1868, one observer stated that
it was impossible to recognise a person’s face three yards off, and
lamplight was needed for reading his chronometer. On the other hand in
Spain in 1860, it was noted that a thermometer, as well as the finest
hand-writing, could be read easily. The foregoing remarks apply to the
state of things in the open air. In 1860, it was stated that inside a
house in Spain the darkness was so great that people moving about had to
take great care lest they should run violently against the household
furniture.
Perhaps on the whole it may be said that the darkness of an ordinary
totality is decidedly greater than that of a full Moon night.
Many observers have noted during totality that even when there has not
been any very extreme amount of absolute darkness, yet the ruddy light
already mentioned as prevailing towards the horizon often gives rise to
weird unearthly effects, so that the faces of bystanders assume a
sickly livid hue not unlike that which results from the light of burning
salt.
METEOROLOGICAL AND OTHER EFFECTS.
It is very generally noticed that great changes take place in the
meteorological conditions of the atmosphere as an eclipse of the Sun
runs its course from partial phase to totality, and back again to
partial phase. It goes without saying that the obstruction of the solar
rays by the oncoming Moon would necessarily lead to a steady and
considerable diminution in the general temperature of the air. This has
often been made the matter of exact thermometric record, but it is not
equally obvious why marked changes in the wind should take place. As the
partial phase proceeds it is very usual for the wind to rise or blow in
gusts and to die away during totality, though there are many exceptions
to this, and it can hardly be called a rule.
The depression of temperature varies very much indeed according to the
locality where the eclipse is being observed and the local thermometric
conditions which usually prevail. The actual depression will often
amount to 10° or 20° and the deposit of dew is occasionally noticed.
In addition to the general effects of a total solar eclipse on men,
animals, and plants as summarised in the extract already made from Mrs.
Todd’s book a few additional particulars may be given culled from many
recorded observations. Flowers and leaves which ordinarily close at
night begin long before totality to show signs of closing up. Thus we
are told that in 1836 “the crocus, gentian and anemone partially closed
their flowers and reopened them as the phenomenon passed off: and a
delicate South African mimosa which we had reared from a seed entirely
folded its pinnate leaves until the Sun was uncovered.” In 1851 “the
night violet, which shortly before the beginning of the eclipse had
little of its agreeable scent about it, smelt strongly during the
totality.”
In the insect world ants have been noticed to go on working during
totality, whilst grasshoppers are stilled by the darkness, and
earth-worms come to the surface. Birds of all kinds seem always upset in
their habits, almost invariably going to roost as the darkness becomes
intensified before totality. In 1868 “a small cock which had beforehand
been actively employed in grubbing about in the sand went to sleep with
his head under his wing and slept for about 10 minutes, and on waking
uttered an expression of surprise, but did not crow.” In 1869 mention is
made of an unruly cow “accustomed to jump into a corn-field at night”
being found to have trespassed into the said corn-field during the total
phase.
The thrilling descriptions of the effects of the oncoming darkness of
totality, derived from the records of past total eclipses, are not
likely to be improved upon in the future, for we shall receive them more
and more from amateurs and less and less from astronomical experts.
Every additional total eclipse which happens testifies to the fact that
the time and thoughts of these latter classes of people will be to an
increasing degree dedicated to instrumental work rather than to simple
naked eye or even telescopic observation. The spectroscope and the
camera are steadily ousting the simple telescope of every sort and
unassisted eye observations from solar eclipse work.
Mrs. Todd has the following apt remarks by way of summary of the results
to an individual of observing a total eclipse of the Sun:—“I doubt if
the effect of witnessing a total eclipse ever quite passes away. The
impression is singularly vivid and quieting for days, and can never be
wholly lost. A startling nearness to the gigantic forces of Nature and
their inconceivable operation seems to have been established.
Personalities and towns and cities, and hates and jealousies, and even
mundane hopes, grow very small and very far away.”
FOOTNOTES:
[Footnote 13: _Month. Not._, R.A.S., vol. xviii. p. 251.]
[Footnote 14: See p. 36 (_ante_).]
[Footnote 15: Mrs. D. P. Todd, _Total Eclipses of the Sun_, p. 21.]
CHAPTER VI.
WHAT IS OBSERVED DURING THE TOTAL PHASE OF AN ECLIPSE OF THE SUN.
The central feature of every total eclipse of the Sun is undoubtedly the
Corona[16] and the phenomena connected with it; but immediately before
the extinction of the Sun’s light and incidental thereto there are some
minor features which must be briefly noticed.
[Illustration: FIG. 8.—BRUSHES OF LIGHT.]
The Corona first makes its appearance on the side of the dark Moon
opposite to the disappearing crescent, but brushes of light are
sometimes observed on the same side, along the convex limb of the
disappearing crescent. The appearance of the brushes will be
sufficiently realised by an inspection of the annexed engraving without
the necessity of any further verbal description. These brushes are
little, if at all, coloured, and must not be confused with the “Red
Flames” or “Prominences” hereafter to be described.
BAILY’S BEADS.
When the disc of the Moon has advanced so much over that of the Sun as
to have reduced the Sun almost to the narrowest possible crescent of
light, it is generally noticed that at a certain stage the crescent
suddenly breaks up into a succession of spots of light. These spots are
sometimes spoken of as “rounded” spots, but it is very doubtful whether
(certainly in view of their supposed cause) they could possibly be
deemed ever to possess an outline, which by any stretch, could be called
“rounded.” Collating the recorded descriptions, some such phrase as
“shapeless beads” of light would seem to be the most suitable
designation. These are observed to form before the total phase, and
often also after the total phase has passed. Under the latter
circumstances, the beads of light eventually run one into another, like
so many small drops of water merging into one big one. The commonly
received explanation of “Baily’s Beads” is that they are no more than
portions of the Sun’s disc, seen through valleys between mountains of
the Moon, the said mountains being the cause why the bright patches are
discontinuous. It is exceedingly doubtful whether this is the true
explanation. The whole question is involved in great uncertainty, and
well deserves careful study during future eclipses; but this it is not
likely to get, in view of the current fashion of every sufficiently
skilled observer concentrating his attention on matters connected with
the solar Corona (observed spectroscopically or otherwise), to the
exclusion of what may be called older subjects of study. I will dismiss
Baily’s Beads from our consideration with the remark that the first
photograph of them was obtained at Ottumwa, Illinois, U.S., during the
eclipse of 1869.
[Illustration: FIG. 9.—“BAILY’S BEADS,” FOUR STAGES, AT BRIEF INTERVALS.
MAY 15, 1836.]
“Baily’s Beads” received their name from Mr. Francis Baily, who, in
1836, for the first time exhaustively described them; but they were
probably seen and even mentioned long before his time. At the total
eclipse of the Sun, seen at Penobscot in North America, on October 27,
1780, they would seem to have been noticed, and perhaps even earlier
than that date.
Almost coincident with the appearance of Baily’s Beads, that is, either
just before or just after, and also just before or just after the
absolute totality (there seems no certain rule of time) jets of red
flame are seen to dart out from behind the disc of the Moon. It is now
quite recognised as a certain fact that these “Red Flames” belong to the
Sun and are outbursts of hydrogen gas. Moreover, they are now commonly
called “Prominences,” and with the improved methods of modern science
may be seen almost at any time when the Sun is suitably approached; and
they are not restricted in their appearance to the time when the Sun is
totally eclipsed as was long supposed.
I may have more to say about these Red Flames later on; but am at
present dealing only with the outward appearances of things.
Carrington’s description has been considered very apt. One which he saw
in 1851 he likened to “a mighty flame bursting through the roof of a
house and blown by a strong wind.”
Certain ambiguous phrases made use of in connection with eclipses of
ancient date may perhaps in reality have been allusions to the Red
Flames; otherwise the first account of them given with anything like
scientific precision seems to be due to a Captain Stannyan, who observed
them at Berne during the eclipse of 1706. His words are that the Sun at
“his getting out of his eclipse was preceded by a blood-red streak from
its left limb which continued not longer than six or seven seconds of
time; then part of the Sun’s disc appeared all of a sudden.”
Some subsequent observers spoke of the Red Flames as isolated jets of
red light appearing here and there; whilst others seem to have thought
they had seen an almost or quite continuous ring of red light around the
Sun. The last-named idea is now recognised as the more accurate
representation of the actual facts, the Red Flames being emanations
proceeding from a sort of shell enveloping the Sun, to which shell the
name of “Chromosphere” has now come to be applied.
As regards the Moon itself during the continuance of the total phase,
all that need be said is that our satellite usually exhibits a disc
which is simply black; but on occasions observers have called it purple
or purplish. Although during totality the Moon is illuminated by a full
allowance of Earth-shine (light reflected by the Earth into space), yet
from all accounts this is always insufficient to reveal any traces of
the irregularities of mountains and valleys, etc., which exist on the
Moon.
When during totality any of the brighter planets, such as Mercury,
Venus, Mars, Jupiter, or Saturn, happen to be in the vicinity of the Sun
they are generally recognised; but the stars seen are usually very few,
and they are only very bright ones of the 1st or 2nd magnitudes. Perhaps
an explanation of the paucity of stars noticed is to be found in the
fact that the minds of observers are usually too much concentrated on
the Sun and Moon for any thought to be given to other things or other
parts of the sky.
Perhaps this is a convenient place in which to recall the fact that
there has been much controversy in the astronomical world during the
last 50 years as to whether there exist any undiscovered planets
revolving round the Sun within the orbit of Mercury. Whilst there is
some evidence, though slight, that one or more such planets have been
seen, opponents of the idea base their scepticism on the fact that with
so many total eclipses as there have been since 1859 (when Lescarbault
claimed to have found a planet which has been called “Vulcan”), no
certain proof has been obtained of the existence of such a planet; and
what better occasion for finding one (if one exists of any size) than
the darkness of a total solar eclipse? At present it must be confessed
that the sceptics have the best of it.
THE CORONA.
We have now to consider what I have already called the central feature
of every total eclipse. It was long ago compared to the nimbus often
placed by painters around the heads of the Virgin Mary and other saints
of old; and as conveying a rough general idea the comparison may still
stand. It has been suggested that not a bad idea of it may be obtained
by looking at a Full Moon through a wire-gauze window-screen. The Corona
comes into view a short time (usually to be measured by seconds) before
the total extinction of the Sun’s rays, lasts during totality and
endures for a brief interval of seconds (or it might be a minute) after
the Sun has reappeared. It was long a matter of discussion whether the
Corona belonged to the Sun or the Moon. In the early days of telescopic
astronomy there was something to be said perhaps on both sides, but it
is now a matter of absolute certainty that it belongs to the Sun, and
that the Moon contributes nothing to the spectacle of a total eclipse of
the Sun, except its own solid body, which blocks out the Sun’s light,
and its shadow, which passes across the Earth.
Of the general appearance of the Corona some idea may be obtained from
Fig. 1 (see Frontispiece) which so far as it goes needs little or no
verbal description. Stress must however be laid on the word “general”
because every Corona may be said to differ from its immediate
predecessor and successor, although, as we shall see presently, there
is strong reason to believe that there is a periodicity in connection
with Coronas as with so many other things in the world of Astronomy. A
curious point may here be mentioned as apparently well established,
namely, that when long rays are noticed in the Corona they do not seem
to radiate from the Sun’s centre as the short rays more or less seem to
do. Though the aggregate brilliancy of the Corona varies somewhat yet it
may be taken to be much about equal on the whole to the Moon at its
full. The Corona is quite unlike the Moon as regards heat for its
radiant heat has been found to be very well marked.
There is another thing connected with the Sun’s Corona which needs to be
mentioned at the outset and which also furnishes a reason for treating
it in a somewhat special manner. The usual practice in writing about
science is to deal with it in the first instance descriptively, and then
if any historical information is to be given to exhibit that separately
and subsequently. But our knowledge of the Sun’s Corona has developed so
entirely by steps from a small beginning that it is neither easy nor
advantageous to keep the history separate or in the background and I
shall therefore not attempt to do so.
Astronomers are not agreed as to what is the first record of the Corona.
It is commonly associated with a total eclipse which occurred in the 1st
century A.D. and possibly in the year 96 A.D. Some details of the
discussion will be found in a later chapter,[17] and I will make no
further allusion to the matter here. Passing over the eclipses of 968
A.D. and 1030 A.D. the records of both of which possibly imply that the
Corona was noticed, we may find ourselves on thoroughly firm ground in
considering the eclipse of April 9, 1567. Clavius, a well-known writer
on chronology, undoubtedly saw then the Corona in the modern acceptation
of the word but thought it merely the uncovered rim of the Sun. In reply
to this Kepler showed by some computations of his own, based on the
relative apparent sizes of the Sun and Moon, that Clavius’s theory was
untenable. Kepler, however, put forth a theory of his own which was no
better, namely, that the Corona was due to the existence of an
atmosphere round the Moon and proved its existence. From this time
forwards we have statements, by various observers, applying to various
eclipses, of the Corona seeming to be endued with a rotatory motion. The
Spanish observer, Don A. Ulloa, in 1778, wrote thus respecting the
Corona seen in that year:—“After the immersion we began to observe round
the Moon a very brilliant circle of light which seemed to have a rapid
circular motion something similar to that of a rocket turning about its
centre.” Modern observations furnish no counterpart of these ideas of
motion in the Corona. Passing over many intervening eclipses we must
note that of 1836 (which gave us “Baily’s Beads”) as the first which set
men thinking that total eclipses of the Sun exhibited subsidiary
phenomena deserving of careful and patient attention. Such attention
was given on the occasion of the eclipses of 1842 and 1851, still
however without the Corona attracting that interest which it has gained
for itself more recently. It was noticed indeed that the Corona always
first showed itself on the side of the Moon farthest from the vanishing
crescent but the full significance of this fact was not at first
realised. Mrs. Todd well remarks:—“In the early observations of the
Corona it was regarded as a halo merely and so drawn. Its real structure
was neither known, depicted, nor investigated. The earliest pictures all
show this. Preconceived ideas prejudiced the observers, and their
sketches were mostly structureless.... It should not be forgotten that
the Coronal rays project outward into space from a spherical Sun and do
not lie in a plane as they appear to the eye in photographs and
drawings.” After remarking on the value of photographs of the Corona up
to a certain point because of their automatic accuracy Mrs. Todd very
sensibly says, “but pencil drawings, while ordinarily less trustworthy
because involving the uncertain element of personal equation are more
valuable in delineating the finest and faintest detail of which the
sensitive plate rarely takes note; the vast array of both, however,
shows marked differences in the structure and form of the Corona from
one eclipse to another though it has not yet revealed rapid changes
during any one observation. This last interesting feature can be studied
only by comparison of photographs near the beginning of an eclipse track
and its end, two or three hours of absolute time apart.” Concerted
efforts to accomplish this were made in 1871, 1887, and 1889, but they
broke down because the weather failed at one or other end of the chain
of observing stations and a succession of photographs not simultaneous
but separated by sufficient intervals of time could not be had. The
eclipse of 1893, however, yielded successful though negative results.
Photographs in South America compared with photographs in Africa two
hours later in time disclosed no appreciable difference in the structure
of the Corona and its streamers. The eclipse of May 28, 1900, will
furnish the next favourable opportunity for a repetition of this
experiment by reason of the fact that the line of totality begins in
North America, crosses Portugal and Spain and ceases in Africa. In other
words, traverses countries eminently calculated to facilitate the
establishment of photographic observing stations where observations can
be made not simultaneously but at successive intervals spread over
several hours.
Although of course the Corona had been observed long before the year
1851, as indeed we have already seen, yet the eclipse of 1851 is the
farthest back which we can safely take as a starting-point for gathering
up thoroughly precise details, because it was the first at which
photography was brought into use. Starting, therefore, with that eclipse
I want to lay before the reader some of the very interesting and
remarkable generalisations which (thanks especially to Mr. W. H.
Wesley’s skilful review of many of the photographic results) are now
gradually unfolding themselves to astronomers. To put the matter in the
fewest possible words there seems little or no doubt that according as
spots on the Sun are abundant or scarce so the Corona when visible
during an eclipse varies in appearance from one period of _eleven_ years
to another like period. Or, to put it in another way, given the date of
a coming total eclipse we can predict to a certain extent the probable
shape and character of the Corona if we know how the forthcoming date
stands as regards a Sun-spot maximum or minimum.
The most recent important eclipses up to date which have been observed,
namely those of April 16, 1893, Aug. 9, 1896, and Jan. 21, 1898, do not
add much to our useful records of the outward appearances presented by
the Corona. The 1896 Corona is described as intermediate between the two
Types respectively associated with years of maximum and minimum
Sun-spots, and this is as it should have been, albeit there was one
extension which reached to about two diameters of the Sun. The 1898
Corona yielded four long Coronal streamers reaching much farther from
the Sun than any previously seen, the two longest reaching to 4½ and 6
diameters of the Sun respectively. These dimensions are quite
unprecedented.
[Illustration: FIG. 10.—CORONA OF 1882. (SUN-SPOT MAXIMUM.)]
The application of the spectroscope to observations of eclipses of the
Sun demands a few words of notice in this place, but it would not be
consistent with the plan of this work to go into details. Though the
spectroscope has been applied under many different circumstances to
different parts of the Sun’s surroundings in connection with total
eclipses yet it is in regard to the Corona that most has been done and
most has been discovered. The substance of the discoveries made is that
the Corona shines with an intrinsic light of its own, that is to say,
that it is composed of constituents whose temperature is sufficiently
elevated to be self-luminous. These constituents are chiefly hydrogen;
the body which corresponds to the line D3 (of Fraunhofer’s scale), and
which has been named “Helium”; and the body which corresponds to the
bright green line 1474 of Kirchoff’s scale and which, since its
existence was first suspected and then assured, has been named
“Coronium.”
The reader will not be surprised to learn, from what has gone before,
that an immense mass of records have accumulated respecting the
appearance of the Corona. Correspondingly numerous and divergent are the
theories which have been launched to explain the observations made. One
thing is in the highest degree probable, namely, that electricity is
largely concerned.
Going back to the question of Sun-spots regarded in their possible or
probable association with the Corona, the present position of matters
appears to be this: that there is a real connection between the general
form of the Corona and disturbances on the Sun, taking Sun-spots as an
indication of solar activity. When Sun-spots are at or near their
maximum, the Corona has generally been somewhat symmetrical, with
synclinal groups of rays making angles of 45° with its general axis. On
the other hand, at the epochs of minimum Sun-spots, the Corona shows
polar rifts much more widely open, with synclinal zones making larger
angles with the axis, and being, therefore, more depressed towards the
equatorial regions, in which, moreover, there is usually a very marked
extension of Coronal matter in the form of elongated streamers reaching
to several diameters of the Sun.
[Illustration: FIG. 11.—CORONA OF 1867. (SUN-SPOT MINIMUM.)]
This generalisation is well borne out by the maximum-epoch Coronas of
1870 and 1871, and the minimum-epoch Coronas of 1867, 1874, 1875, 1878,
and perhaps 1887, and certainly 1889. On the other hand, the eclipses of
1883, 1885 and 1886 do not strikingly confirm this theory. The eclipse
of 1883 was at a time of rapidly decreasing solar activity, yet the
Corona had the features of a Sun-spot maximum. The same, though in a
somewhat less degree, may be said of the eclipses of 1885 and 1886. At
the times of both of these eclipses the solar activity was decreasing.
The forthcoming eclipse of 1900 will nearly coincide with a Sun-spot
minimum, and if the above conclusions are well founded the Corona in
1900 should resemble that of 1889, and be characterised by, amongst
other things, some very elongated groups of rays extending in nearly
opposite directions.
We are still a long way off from being able to state with perfect
confidence what the Corona is. It is certainly a complex phenomenon, and
the various streamers which we see are not, as was at one time imagined,
a simple manifestation of one radiant light. Mrs. Todd thus conveniently
summarises the present state of our knowledge:—“The true corona appears
to be a triple phenomenon. First, there are the polar rays, nearly
straight throughout their visible extent. Gradually, as these rays start
out from points on the solar disc farther and farther removed from the
poles, they acquire increasing curvature, and very probably extend into
the equatorial regions, but are with great difficulty traceable there,
because projected upon and confused with the filaments having their
origin remote from the poles. Then there is the inner equatorial corona,
apparently connected intimately with truly solar phenomena, quite like
the polar rays; while the third element in the composite is the outer
equatorial corona, made up of the long ecliptic streamers, for the most
part visible only to the naked eye, also existing as a solar appendage,
and possibly merging into the zodiacal light. The total eclipses of a
half century have cleared up a few obscurities, and added many
perplexities. There is little or no doubt about the substantial, if not
entire, reality of the corona as a truly solar phenomenon. The Moon, if
it has anything at all to do with the corona, aside from the fact of its
coming in conveniently between Sun and Earth, so as to allow a brief
glimpse of something startlingly beautiful which otherwise could never
have been known, is probably responsible for only a very narrow ring of
the inner radiance of pretty even breadth all round. This diffraction
effect is accepted; but the problem still remains how wide this annulus
may be, and whether it may vary in width from one eclipse to another.
These questions once settled, the spurious structure may then be
excerpted from the true. Indeed the coronal streamers, delicately
curving and interlacing, may tell the whole story of the Sun’s radiant
energy.”
FOOTNOTES:
[Footnote 16: There seems sufficient evidence to show that the
Corona may be seen even on occasions when the Sun is not totally
eclipsed, provided that the visible crescent of the Sun is
exceedingly narrow.]
[Footnote 17: See p. 130 (_post_).]
CHAPTER VII.
WHAT IS OBSERVED AFTER THE TOTAL PHASE
OF AN ECLIPSE OF THE SUN IS AT AN END.
In a certain sense, a description of the incidents which precede the
total disappearance of the Sun in connection with a total Eclipse will
apply more or less to the second half of the phenomenon; only, of
course, in the reverse order and on the opposite side of the compass.
The Corona having appeared first of all on the W. side of the Sun, then
having shown itself complete as surrounding the Sun, will begin to
disappear on the W. side, and will be last seen on the E. side. Baily’s
Beads may or may not come into view; the Sun will reappear first as a
very thin crescent, gradually widening; the quasi-nocturnal darkness
visible on the Earth will cease, and eventually the Moon will completely
pass away from off the Sun, and the Sun once again will exhibit a
perfect circle of light.
Whilst there is so much to look for and look at and think about, one
thing must be sought for instantly after totality, or it will be gone
for ever, and that is the Moon’s shadow on the Earth. We have already
seen in the last chapter the startling rapidity and solemnity with
which the shadow seems to rush forward to the observer from the horizon
on the western side of the Meridian. Passing over him, or even, so to
speak, through him, it travels onwards in an easterly direction and very
soon vanishes. Its visibility at all depends a good deal upon whether
the observer, who is looking for it, is sufficiently raised above the
adjacent country to be able to command at least a mile or two of ground.
If he is in a hollow, he will have but little chance of seeing the
shadow at all: on the other hand, if he is on the top of a considerable
hill (or high up on the side of a hill), commanding the horizon for a
distance of 10 or 20 miles, he will have a fair chance of seeing the
shadow. Sir G. B. Airy states, in 1851, “My eye was caught by a
duskiness in the S.E., and I immediately perceived that it was the
Eclipse-shadow in the air, travelling away in the direction of the
shadow’s path. For at least six seconds, this shadow remained in sight,
far more conspicuous to the eye than I had anticipated. I was once
caught in a very violent hail and thunder-storm on the Table-land of the
County of Sutherland called the “Moin,” and I at length saw the storm
travel away over the North Sea; and this view of the receding
Eclipse-shadow, though by no means so dark, reminded me strongly of the
receding storm. In ten or twelve seconds all appearance of the shadow
had passed away.”
Perhaps this may be a convenient place to make a note of what seems to
be a fact, partly established at any rate, even if not wholly
established, namely—that there seems some connection between eclipses
of the Sun and Earthquakes. A German physicist named Ginzel[18] has
found a score of coincidences between solar eclipses and earthquakes in
California in the years between 1850 and 1888 inclusive. Of course there
were eclipses without earthquakes and earthquakes without eclipses, but
twenty coincidences in thirty-eight years seems suggestive of something.
FOOTNOTES:
[Footnote 18: _Himmel und Erde_, vol. ii. pp. 255, 309; 1890.]
CHAPTER VIII.
ECLIPSES OF THE SUN MENTIONED IN HISTORY—CHINESE.
This is the first of several chapters which will be devoted to
historical eclipses. Of course the total eclipse of the Sun of August 9,
1896, observed in Norway and elsewhere, is, in a certain sense, an
eclipse mentioned in history, but that is not what is intended by the
title prefixed to these chapters. By the term “historical eclipses,” as
used here, I mean eclipses which have been recorded by ancient
historians and chroniclers who were not necessarily astronomers, and who
wrote before the invention of the telescope. The date of this may be
conveniently taken as a dividing line, so that I shall deal chiefly with
eclipses which occurred before, say, the year 1600. There is another
reason why some such date as this is a suitable one from which to take a
new departure. Without at all avowing that superstition ceased on the
Earth in the year 1600 (for there is far too large a residuum still
available now, 300 years later), it may yet be said that the Revival of
Letters did do a good deal to divest celestial phenomena of those
alarming and panic-causing attributes which undoubtedly attached to them
during the earlier ages of the world and during the “Dark Ages” in
Western Europe quite as much as during any other period of the world’s
history. No one can examine the writings of the ancient Greek and Roman
historians, and the chronicles kept in the monasteries of Western Europe
by their monkish occupiers, without being struck by the influence of
terror which such events as eclipses of the Sun and Moon and such
celestial visitors as Comets and Shooting Stars exercised far and wide.
And this influence overspread, not only the unlettered lower orders, but
many of those in far higher stations of life who, one might have hoped,
would have been exempt from such feelings of mental distress as they
often exhibited. Illustrations of this fact will be adduced in due
course.
It has always been supposed that the earliest recorded eclipse of the
Sun is one thus mentioned in an ancient Chinese classic—the _Chou-King_
(sometimes spelt _Shou-Ching_). The actual words used may be
translated:—“On the first day of the last month of Autumn the Sun and
Moon did not meet harmoniously in Fang.” To say the least of it, this is
a moderately ambiguous announcement, and Chinese scholars, both
astronomers and non-astronomers, have spent a good deal of time in
examining the various eclipses which might be thought to be represented
by the inharmonious meeting of the Sun and the Moon as above recorded.
To cut a long story short, it is generally agreed that we are here
considering one or other of two eclipses of the Sun which occurred in
the years 2136 or 2128 B.C. respectively, the Sun being then in the
sidereal division “Fang,” a locality determined by the stars β, δ, π,
and ρ Scorpii, and which includes a few small stars in Libra and
Ophiuchus to the N. and in Lupus to the S. How this simple and neat
conclusion, which I have stated with such apparent dogmatism, was
arrived at is quite another question, and it would hardly be consistent
with the purpose of this volume to attempt to work it out in detail, but
a few points presented in a summary form may be interesting.
In the first place, be it understood, that though it is fashionable to
cast ridicule on John Chinaman, especially by way of retaliation for his
calling us “Barbarians,” yet it is a sure and certain fact that not only
have the Chinese during many centuries been very attentive students of
Astronomy, but that we Westerns owe a good deal of our present knowledge
in certain departments to the information stored up by Chinese observers
during many centuries both before and after the Christian Era.
This, however, is a digression. The circumstances of this eclipse as
regards its identification having been carefully examined by Mr. R. W.
Rothman,[19] in 1839 were further reviewed by Professor S. M. Russell
in a paper published in the proceedings of the Pekin Oriental
Society.[20] The substance of the case is that in the reign of
Chung-K’ang, the fourth Emperor of the Hsia Dynasty, there occurred an
eclipse of the Sun, which is interesting not only for its antiquity, but
also for the dread fate of the two Astronomers Royal of the period, who
were taken by surprise at its occurrence, and were unprepared to perform
the customary rites. These rites were the shooting of arrows and the
beating of drums, gongs, etc., with the object of delivering the Sun
from the monster which threatened to devour it. The two astronomers by
virtue of their office should have superintended these rites. They were,
however, drunk and incapable of performing their duties, so that great
turmoil ensued, and it was considered that the land was exposed to the
anger of the gods. By way of appeasing the gods, and of suitably
punishing the two State officials for their neglect and personal
misconduct, they were forthwith put to death, a punishment which may be
said to have been somewhat excessive, in view of the fact that the
eclipse was not a total but only a partial one. An anonymous verse
runs:—
Here lie the bodies of Ho and Hi,
Whose fate though sad was visible—
Being hanged because they could not spy
Th’ eclipse which was invisible.
It appears beyond all reasonable doubt that the eclipse in question
occurred on October 22, 2136 B.C. The preliminary difficulties to be
got over in arriving at the date arose from the fact that there was an
uncertainty of 108 years in the date when the Emperor Chung-K’ang
ascended the throne; and within these limits of time there were 14
possible years in which an eclipse of the Sun in Fang could have
occurred. Then the number was further limited by the necessity of
finding an eclipse which could have been seen at the place which was the
Emperor’s capital. The site of this, again, was a matter of some
uncertainty. However, step by step, by a judicious process of
exhaustion, the year 2136 B.C. was arrived at as the alternative to the
previously received date of 2128 B.C. Considering that we are dealing
with a matter which happened full 4000 years ago, it may fairly be said
that this discrepancy is not perhaps much to be wondered at, seeing what
disputes often happen nowadays as to the precise date of events which
may have occurred but a few years or even a few months before the
controversy springs up.
Professor Russell says that:—“Some admirers of the Chinese cite this
eclipse as a proof of the early proficiency attained by the Chinese in
astronomical calculations. I find no ground for that belief in the text.
Indeed, for many centuries later, the Chinese were unable to predict the
position of the Sun accurately among the stars. They relied wholly on
observation to settle their calendar, year by year, and seem to have
drawn no conclusions or deductions from their observations. Their
calendar was continually falling into confusion. Even at the beginning
of this dynasty, when the Jesuits came to China, the Chinese
astronomers were unable to calculate accurately the length of the shadow
of the Sun at the equinoxes and solstices. It seems to me therefore very
improbable that they could have been able to calculate and predict
eclipses.”
I am not at all sure that this is quite a fair presentation of the case.
I do not remember ever to have seen the power to predict eclipses
ascribed to the Chinese, but it is a simple matter of fact that we owe
to them during many centuries unique records of a vast number of
celestial phenomena. Their observations of comets may be singled out as
having been of inestimable value to various 19th-century computers,
especially E. Biot and J. R. Hind.
The second recorded eclipse of the Sun would seem to be also due to the
Chinese. Confucius relates that during the reign of the Emperor Yew-Wang
an eclipse took place. This Emperor reigned between 781 B.C. and 771
B.C., and it has been generally thought that the eclipse of 775 B.C. is
the one referred to, but Johnson doubts this on the ground that this
eclipse was chiefly visible in the circumpolar regions, and if seen at
all in China must have been of very small dimensions. He leans to the
eclipse of June 4, 780 B.C. as the only large one which happened within
the limits of time stated above.
An ancient Chinese historical work, known as the _Chun-Tsew_, written by
Confucius, makes mention of a large number of solar eclipses which
occurred before the Christian Era. This work came under the notice of M.
Gaubil, one of the French Jesuit missionaries who laboured in China
some century and a half ago, and he first gave an account of it in his
_Traité de la Chronologie Chinoise_, published at Paris in 1770.[21]
The _Chun-Tsew_ is said to be the only work really written by
Kung-Foo-Tze, commonly known as Confucius, the other treatises
attributed to him having been compiled by disciples of his either during
his life-time or after his decease. The German chronologist, Ideler, was
acquainted with this work, and in a paper of his own, presented to the
Berlin Academy, remarked:—“What gives great interest to this work is the
account of 36 solar eclipses observed in China, the first of which was
on Feb. 22, 720 B.C., and the last on July 22, 495 B.C.”
In 1863 Mr. John Williams, then Assistant Secretary of the Royal
Astronomical Society, communicated to the Society in a condensed form
the particulars of these eclipses as related in Confucius’s book,
together with some remarks on the book itself. The _Chun-Tsew_ treats of
a part of the history of the confederated nations into which China was
divided during the Chow Dynasty, that is between 1122 B.C. and 255 B.C.
The particular period dealt with is that which extended from 722 B.C. to
479 B.C. It was during the latter part of this interval of about 242
years that Confucius flourished. But the book is not quite a general
history for it is more particularly devoted to the small State of Loo
of which Confucius was a native, where he passed a great portion of his
life, and where he was advanced to the highest honours. It contains the
history of twelve princes of this State with incidental notices of the
other confederated nations. The number of the years of each reign is
accurately determined, and the events are classed under the years in
which they occurred. Each year is divided into sections according to the
four seasons, Spring, Summer, Autumn, Winter, and the sections are
subdivided into months, and often the days are distinguished. The name
_Chun-Tsew_ is said to have been given to this work from its having been
commenced in Spring and finished in Autumn, but Williams thinks that the
name rather refers to the fact that its contents are divided into
seasons as stated. The style in which it is written is very concise,
being a bare mention of facts without comment, and although on this
account it might appear to us dry and uninteresting, it is much valued
by the Chinese as a model of the ancient style of writing. It forms one
of the _Woo-King_ or Five Classical Books, without a thorough knowledge
of which, and of the _Sze-Shoo_ or Four Books, no man can attain to any
post of importance in the Chinese Empire.
The account of each eclipse is but little more than a brief mention of
its occurrence at a certain time. The following is an example of the
entries:—“In the 58th year of the 32nd cycle in the 51st year of the
Emperor King-Wang, of the Chow Dynasty, the 3rd year of Yin-Kung, Prince
of Loo, in the spring, the second moon, on the day called Kea-Tsze,
there was an eclipse of the Sun.” This 58th year of the 32nd cycle
answers to 720 B.C. Mr. Williams in the year 1863 presented to the Royal
Astronomical Society a paper setting out the whole of the eclipses of
which I have cited but one example, converting, of course, the very
complicated Chinese dates into European dates.
These Chinese records of eclipses were in 1864 subjected to examination
by the late Sir G. B. Airy,[22] with results which were highly
noteworthy, and justify us in reposing much confidence in Chinese
astronomical work. Airy remarks:—“The period through which these
eclipses extend is included in the time through which calculations of
eclipses have been made in the French work entitled _L’Art de vérifier
les Dates_. I have several times had occasion to recalculate with great
accuracy eclipses which are noted in that work (edition of 1820), and I
have found that, to the limits of accuracy to which it pretends, and
which are abundantly sufficient for the present purpose, it is perfectly
trustworthy. I have therefore made a comparison of the _Chun-Tsew_
eclipses with those of _L’Art de vérifier les Dates_. The result is
interesting. Of the 36 eclipses, 32 agree with those of the _Art de
vérifier les Dates_, not only in the day, but also in the general track
of the eclipse as given in the _Art de vérifier_, which appears to show
sufficiently that the eclipse would be visible in that province of China
to which the _Chun-Tsew_ is referred.” Airy then proceeds to point out
that, with regard to the four eclipses which he could not confirm, there
cannot have been eclipses in April 645 B.C. or in June 592 B.C. It
appears, however, from a note by Williams, that the date attached to the
eclipse of 645 B.C. is, in reality, an erroneous repetition (in the
Chinese mode of expressing it) of that attached to the next following
one, and in the absence of correct date it must be rejected. In the
record of 592 B.C., June 16, no clerical error is found, and there must
be an error of a different class. The eclipses of 552 B.C., September
19, and 549 B.C., July 18, to which there is nothing corresponding in
the _Art de vérifier_, are in a different category. These occur in the
lunations immediately succeeding 552 B.C., August 20, and 549 B.C., June
19, respectively, and there is no doubt that those which agree with the
_Art de vérifier_ were real eclipses. Now there cannot be eclipses
visible at the same place in successive lunations, because the
difference of the Moon’s longitudes is about 29°, and the difference of
latitudes is therefore nearly 3°, which is greater than the sum of the
diameters of the Sun and Moon increased by any possible change of
parallax for the same place. These, therefore, were not real eclipses.
It seems probable that the nominal days were set down by the observer in
his memorandum book as days on which eclipses were to be looked for.
Airy conjectured that the eclipses of 552 B.C., August 20, and 549 B.C.,
June 19, were observed by one and the same person, and that he possessed
science enough to make him connect the solar eclipses with the change
of the Moon, but not enough to give him any idea of the limitations to
the visibility of an eclipse.
On a subsequent occasion Mr. Williams laid before the Society a further
list of solar eclipses observed in China, and extending from 481 B.C. to
the Christian Era. He collected these from a Chinese historical work,
entitled _Tung-Keen-Kang-Muh_. This work, which runs to 101 volumes,
contains a summary of Chinese history from the earliest times to the end
of the Yuen Dynasty, A.D. 1368, and was first published about 1473. The
copy in Mr. Williams’s possession was published in 1808. The text is
very briefly worded, and consists merely of an account of the accessions
and deaths of the emperors and of the rulers of the minor states, with
some of the more remarkable occurrences in each reign. The appointments
and deaths of various eminent personages are also noticed, together with
special calamities such as earthquakes, inundations, storms, etc. The
astronomical allusions include eclipses and comets. Amongst the eclipses
are also all, or most of those which are recorded in the _Chun-Tsew_ as
having occurred prior to 479 B.C. Though no particular expressions are
used to define the exact character of the eclipses, it is to be presumed
that some of them must have been total, because it is stated that the
stars were visible, albeit that seemingly in only one instance is a word
attached which specifically expresses the idea of totality. Here again
all the dates were expressed in Chinese style, but, as published by
Williams, were rendered, as before, in European style by aid of
chronological tables, published about 1860 in Japan. Mr. Williams, in
his second paper, from which I have been quoting, states that he brought
his published account down to the Christian Era only as a matter of
convenience, but that he had in hand a further selection of eclipses
from the _Tung-Keen-Kang-Muh_, the interval from the Christian Era to
the 4th century A.D. yielding nearly 100 additional eclipses. This
further transcript has not yet been published, but remains in MS. in the
Library of the Royal Astronomical Society. Mr. Williams died in 1874 at
the age of 77, one of the most experienced Chinese scholars of the
century.
It is remarkable that none of the Chinese annals to which reference has
been made include any mention of eclipses of the Moon; but the records
of Comets are exceedingly numerous and, as I have already stated, have
proved of the highest value to astronomers who have been called upon to
investigate the ancient history of Comets.
FOOTNOTES:
[Footnote 19: _Memoirs_, R.A.S., vol. xi. p. 47.]
[Footnote 20: Republished in the _Observatory_ Magazine, vol. xviii.
p. 323, _et seq._, 1895.]
[Footnote 21: A good deal of information respecting Chinese eclipse
records, so far as known up to the beginning of the 19th-century,
will be found in Delambre’s _Histoire de l’Astronomie Ancienne_.
Paris, 1817.]
[Footnote 22: _Month. Not._, R.A.S., vol. xxiv. p. 41.]
CHAPTER IX.
ARE ECLIPSES ALLUDED TO IN THE BIBLE?
An interesting question has been suggested: Are there any allusions to
eclipses to be found in Holy Scripture? It seems safe to assert that
there is at least one, and that there may be three or four.
In Amos viii. 9 we read:—“I will cause the Sun to go down at noon, and I
will darken the Earth in the clear day.” This language is so very
explicit and applies so precisely to the circumstances of a solar
eclipse that commentators are generally agreed that it can have but one
meaning;[23] and accordingly it is considered to refer without doubt to
one or other of the following eclipses:—791 B.C., 771 B.C., 770 B.C., or
763 B.C. Archbishop Usher,[24] the well-known chronologist, suggested
the first three more than two centuries ago, whilst the eclipse of 763
B.C. was suggested in recent times and is now generally accepted as the
one referred to. The circumstances connected with the discovery and
identification of the eclipse of 763 B.C. are very interesting.
The date when Amos wrote is set down in the margin of our Bibles as 787
B.C. and if this date is correct it follows that for his statement to
have been a prediction he must be alluding to some eclipse of later date
than 787 B.C. This obvious assumption not only shuts out the eclipse of
791 B.C., but opens the door to the acceptance of the eclipse of 763
B.C.
Apparently the first modern writer who looked into the matter after
Archbishop Usher was the German commentator Hitzig who suggested the
eclipse of Feb. 9, 784 B.C. Dr. Pusey was so far taken with this idea
that he thought it worth while to secure the co-operation of the Rev. R.
Main, F.R.A.S., the Radcliffe Observer at Oxford, for the purpose of a
full investigation. Mr. Main had the circumstances of that eclipse
calculated, with the result that though the eclipse was indeed total in
Africa and Hindostan, yet at Samaria it was only partial and of no
considerable magnitude. Dr. Pusey’s words, summing up the situation
are:—“The eclipse then would hardly have been noticeable at Samaria,
certainly very far indeed from being an eclipse of such magnitude, as
could in any degree correspond with the expression, ‘I will cause the
Sun to go down at noon.’” ... “Beforehand, one should not have expected
that an eclipse of the Sun, being itself a regular natural phenomenon,
and having no connection with the moral government of God, should have
been the subject of the prophet’s prediction. Still it had a religious
impressiveness then, above what it has now, on account of that
wide-prevailing idolatry of the Sun. It exhibited the object of their
false worship, shorn of its light, and passive.”
Dr. Pusey’s _Commentary_ from which the above quotation is made[25]
bears the date 1873, but he appears not to have been acquainted with the
important discovery announced no less than six years previously by the
distinguished Oriental scholar, Sir H. C. Rawlinson. The discovery to
which I allude is a contemporary record on an Assyrian tablet of a solar
eclipse which was seen at Nineveh about 24 years after the reputed date
of Amos’s prophecy. This tablet had been described by Dr. Hinckes in the
British Museum _Report_ for 1854 but its chronological importance had
not then been realised. Sir H. Rawlinson[26] speaks of the tablet as a
record of or register of the annual archons at Nineveh. He says:—“In the
eighteenth year before the accession of Tiglath-Pileser there is a
notice to the following effect—‘In the month Sivan an eclipse of the Sun
took place’ and to mark the great importance of the event a line is
drawn across the tablet although no interruption takes place in the
official order of the Eponymes. Here then we have notice of a solar
eclipse which was visible at Nineveh which occurred within 90 days of
the (vernal) equinox (taking that as the normal commencement of the
year) and which we may presume to have been total from the prominence
given to the record, and these are conditions which during a century
before and after the era of Nabonassar are alone fulfilled by the
eclipse which took place on June 15, 763.”
This record was submitted to Sir G. B. Airy and Mr. J. R. Hind, and the
circumstances of the eclipse were computed by the latter, by the aid of
Hansen’s Lunar Tables and Le Verrier’s Solar Tables. The result, when
plotted on a map, showed that the shadow line just missed the site of
Nineveh, but that a very slight and unimportant deviation from the
result of the Tables would bring the shadow over the city of Nineveh
where the eclipse was observed, and over Samaria where it was predicted.
The identification of this eclipse, both as regards its time and place,
has also proved a matter of importance in the revision of Scripture
chronology, by lowering, to the extent of 25 years, the reigns of the
kings of the Jewish monarchy. The need for this revision is further
confirmed, if we assume that the celebrated incident in the life of King
Hezekiah, described as the retrogradation of the Sun’s shadow on the
dial of Ahaz, is to be interpreted as connected with a partial eclipse
of the Sun.
We will now consider this event, and see what can be made out of it. One
Scripture record (2 Kings xx. 11) is as follows:—“And Isaiah the prophet
cried unto the Lord: and he brought the shadow ten degrees backward, by
which it had gone down in the dial of Ahaz.” This passage has greatly
exercised commentators of all creeds in different ages of the Church;
and the most divergent opinions have been expressed as to what happened.
This has been due to two causes jointly. Not only is the occurrence
incomprehensible, looked at on the surface of the words, but we are
entirely ignorant of the construction of the so-called “dial” of Ahaz,
and have little or no material directly available from outside sources
to enable us to come to a clear and safe conclusion. No doubt, however,
it was a sun-dial, or gnomon of some kind. Bishop Wordsworth lays stress
on the apparent assertion that the miracle was not wrought on any other
dial at Jerusalem except that of Ahaz, the father of Hezekiah, and he
treats as a confirmation of this the statement in 2 Chron. xxxii. 31,
that ambassadors came from Babylon to Jerusalem, being curious to learn
all about “the wonder that had been done in the land” (_i.e._ in the
land of Judah). But there is more taken for granted here than is
necessary, or, as we shall presently see, is justifiable. To begin with,
how do we know that there was any other dial at Jerusalem like that of
Ahaz? But, in point of fact, we must make a new departure altogether,
for it has been suggested (I know not exactly by whom, or when for the
first time) that an eclipse of the Sun, under certain circumstances,
would explain all that happened, and reconcile all that has to be
reconciled. What happened to Hezekiah is thought by many to imply
clearly a miracle, and it may be said that an eclipse of the Sun cannot
be held to be a miracle[27] by the ordinary definition of the word. But,
on the other hand, it certainly might count as such in the eyes of
ignorant spectators, who know nothing of the theory or practice of
eclipses, and who would regard such a thing as quite unforeseen,
unexpected, and alarming. Illustrations of this might be multiplied from
all parts of the world, in all ages of the world’s history.
Let us see now what the argument is, as it was worked out by the late
Mr. J. W. Bosanquet, F.R.A.S. Shortly before the invasion of Judæa by
Sennacherib—say in the beginning of the year 689 B.C.—Hezekiah was sick
unto death. In answer to his fervent prayer for recovery the prophet
Isaiah was sent to him with this message:—“Thus saith the Lord, the God
of David thy Father, I have heard thy prayer, I have seen thy tears;
behold, I will add unto thy days fifteen years ... and I will defend
this city, and this shall be a sign unto thee from the Lord, that the
Lord will do this thing that He hath spoken. Behold, I will bring again
the shadow of the degrees, which is gone down in the sun-dial of Ahaz
ten degrees backward. So the Sun returned ten degrees, by which degrees
it had gone down.” (Isaiah xxxviii. 5-8).
In these words we evidently have mention of some instrument erected in
Hezekiah’s palace, in the days of his father Ahaz, for showing the
change in the position of the shadow cast by the Sun from day to day.
This statement is confirmed by a profane writer, Glycas, who states:
“They say that Ahaz, by some contrivance, had erected in his palace
certain steps, which showed the hours of the day, and also measured the
course of the Sun.”
The idea involved in “bringing again,” through “ten degrees backward,”
“the shadow of the degrees” which had gone down, is very noteworthy. We
seem intended to learn from these words several things. For one thing
(to begin with) that the steps (as we must consider them to have been)
on this sun-dial of Ahaz, were turned away from the Sun. For only in
that position could they cast their shadow, or could the number of the
illuminated steps be varied, upwards or downwards, according to the
varying altitude of the sun. The only conceivable use of a fixed
instrument so placed would be to show the rise and fall of the shadow
from day to day, as the Sun on the meridian gradually rose higher
between mid-winter and mid-summer, or descended lower between mid-summer
and mid-winter, in passing of course through the winter and summer
solstices in turn. No simple motion of the Sun in its ordinary diurnal
progress would produce the effect described. On the other hand, it is
equally clear that the shadow cast by a gnomon properly adjusted at the
head of such a series of steps would travel upwards and downwards upon
the steps “with the Sun,” from winter to summer and from summer to
winter, indicating at each noon the meridian altitude of the Sun from
day to day, the latitude of Jerusalem being 31° 47′, and the Sun’s
altitude there on the shortest day being 34° 41′. If the gnomon were
raised above the topmost step so as to bring the tip of the gnomon or
any aperture in it so much above the step as would be the equivalent of
2° 54′ or slightly more, then the top of the shadow of the gnomon (or a
spot of light passing through a hole in it) would, on the shortest day
of the year, fall just beyond the lowermost step. An instrument
constructed on the principle just set forth was known to and used by the
Greek astronomers of antiquity under the name of a _Sciotheron_ or
shadow-taker. Sometimes, and perhaps more properly, it was called a
_Heliotropion_, that is, an instrument designed to indicate the turning
of the Sun at the Tropics.[28] This, be it remembered, was information
needed by the ancients for the correct regulation of the seasons of the
year, and of special service to the Jews whose greater festivals were
fixed in connection with the seasons. There is reason to believe that
instruments of this character were of early invention, going back
perhaps to the times of Homer, for we find a passage in the _Odyssey_,
(xv. 403) as follows:—
“Above Ortygia lies an isle of fame
Far hence remote, and Syria [Syros] is the name;
There curious eyes inscrib’d with wonder trace
The Sun’s diurnal and his summer race.”
Pope’s rendering of this passage fails, however, to bring out the
salient idea involved. Butcher and Lang translate the passage
thus:—“There is a certain isle called Syria, if haply thou hast heard
tell of it, over above Ortygia, and there are the turning-places of the
Sun.” Merry[29] calls these island names mere “inventions of the poet.”
It seems to me a great question whether Homer’s words really support the
statement I have made just before quoting it.
Diogenes Laërtius refers to this same instrument when he speaks of the
Heliotropion preserved in the Island of Syra.[30]
According to Laërtius, Anaximander[31] was the first Greek to use
gnomons, which he placed on the Sciothera of Lacedæmon, for the express
purpose of indicating the Tropics and Equinoxes. These Sciothera were
pyramidal in form.
An obelisk was the simplest, though an imperfect form of Heliotropion,
marking indistinctly the length of a shadow at different times of the
year, especially the extremes of length and shortness at mid-winter and
mid-summer. It is perhaps interesting to mention that travellers have
recorded, in various places, various devices for furnishing information
respecting these matters. For instance, in Milan Cathedral the meridian
line is marked on the pavement, and along this line, an image of the Sun
coming through an aperture in the southern wall travels backwards and
forwards during the year according to the seasons. Some Jesuit
missionaries who visited China about the middle of the last century,
noticed a device of this character in operation at the Observatory at
Pekin. A gnomon had been set up in a low room and one of the
missionaries, M. Le Comte, describes in the following words what they
saw in connection with this gnomon:—“The aperture through which the rays
of the Sun came was about 8 ft. above the floor; it is horizontal and
formed of two pieces of copper, which may be turned so as to be farther
from, or closer to, each other to enlarge or contract the aperture.
Lower was a table with a brass plate in the middle on which was traced a
meridian line 15 ft. long, divided by transverse lines which are neither
finished nor exact. All round the table there are small channels to
receive the water, whereby it is to be levelled.”[32]
All this may seem rather a digression, and so it is, but I am following
Mr. Bosanquet herein in order the better to justify the argument that
it was an eclipse of the Sun which marked the important incident in
Hezekiah’s life which has been handed down to us by the sacred writer.
It is evident that if a flight of steps were erected on the principles
which were set forth above, the steps sloping upwards and southwards
(for the Northern Hemisphere) from the lowest step to within a few
inches below an aperture in the gnomon suitably arranged, the ray or
image of the Sun, whichever it was, would travel day by day up and down
such steps between solstice and solstice. We may conclude, therefore,
that the instrument which Hezekiah gazed at, and which is called in
Scripture, the “Dial” of Ahaz, was what the Greeks would have termed a
Heliotropion.
The historian’s record is to the effect that on the day of Hezekiah’s
recovery an extraordinary motion of the shadow was observed on the
“Steps of Ahaz” by the rising of the shadow “ten steps” from the point
to which it had “gone down with the Sun.” This effect is spoken of not
as a miracle but as “a sign.” It should also be remembered that the cure
of Hezekiah was effected not by a miracle but by a simple application of
a lump of figs. The promise of his recovery was confirmed by the motion
of the shadow as already stated. We are justified, therefore, in looking
for some ordinary natural phenomenon by which to account for this
peculiar motion on the dial, and something miraculous is not essential.
Dean Milman once suggested that the effect might have been produced “by
a cloud refracting the light.” No doubt a dark cloud might produce an
apparent interference with the shadow, but it is well pointed out by
Bosanquet that such a cause as a cloud would have been so manifest to
everyone, and the effect so transient, that the phenomenon could hardly
have been referred to afterwards as it was in another place as “a wonder
that was done in the land.” (2 Chron. xxxii. 31).
It becomes, therefore, alike an obvious and a simple explanation that a
shadow caused by the Sun might be deflected downwards on such an
instrument with a regular and steady motion by the Moon passing slowly
over the upper part of the Sun’s disc, as Sun and Moon both approached
the meridian.
The critical question has now to be raised: “Can astronomers inform us
whether a considerable eclipse of the Sun occurred at the beginning of
the year 689 B.C. anywhere near noon and which was visible at
Jerusalem?” And the answer to this it is interesting to be able to say
is a plain and distinct affirmative. There was a large partial eclipse
of the Sun on January 11, 689 B.C., about 11.30 A.M., and it was the
upper limb which underwent eclipse.
This eclipse fulfils all the requirements of the case, both from the
historian’s and the astronomer’s point of view. It occurred about the
year fixed by Demetrius as that of Hezekiah’s illness: it occurred while
the Sun was approaching and actually passing the meridian; the
obscuration was on that part of the Sun’s disc (namely the upper part)
which would have had the effect of causing the point of light, which
would seem to emanate from the Sun, to appear to be depressed downwards;
and it was visible at Jerusalem. But there still remains for
consideration the final and most important question, “Would a deflection
of light proceeding from the Sun, regarded as a moving body, be capable
of affecting, to the extent of ‘ten steps,’ the shadow on such an
instrument as has been described?” And arising out of this, there is the
subordinate question, “Would January, being the month when this eclipse
certainly occurred, also be a month suitable for the exhibition of such
a phenomenon?”
It is ascertainable by calculation that the time occupied by the Moon in
passing over the Sun, in the way it did during this eclipse, was about
2½ hours. But from the time of central conjunction, when the
obscuration was the greatest and the point of light depressed the most,
to the time when the uppermost portion of the Sun’s disc was released by
the eastward motion of the Moon, and the light from that uppermost
portion was again manifest, was about 20 minutes, and this, therefore,
was the time during which the phenomenon of retrogression on the “steps”
would have been exhibited to the King’s eyes. Assuming then that the
time when the ascending shadow had travelled upwards to the tenth step
coincided, or nearly so, with the time when the Sun had reached its
highest altitude for the day, at noon, we infer that the time of central
conjunction during this eclipse was not later than from 20 to 15
minutes before noon. It could not have been much earlier, because the
phenomenon of the resting of the shadow for a time at its _apparently_
highest point for the day (which preceded the promise that it should
rise ten steps) has also to be accounted for, and this cessation of its
motion upwards could not have taken place till about 25 minutes before
noon, when the decreasing motion of the Sun in altitude (or its
slackening motion upwards as it approached mid-day) would have become
counteracted by the coming on of the eclipse. Now at 11.35 A.M. the
sun’s disc would have risen to the altitude of 35° 8′; and the highest
visible point of light would, owing to the eclipse, then have been about
35° 4′; and at 11.40 A.M., being the time of greatest obscuration, the
extreme cusps of light produced by the intervention of the Moon would
still have stood at about 35° 4′, just 23′ below the highest point of
light at noon (Fig. 12). _The whole disc of the sun had now risen above
the gnomon, yet no motion of the shadow on the steps had been observed
for fully five minutes. The time shown by the dial was seemingly
mid-day._
[Illustration: FIG. 12.—ECLIPSE OF THE SUN, JANUARY 11, 689 B.C., AT
JERUSALEM.]
Sun’s apparent semi-diameter 16′ 13″
Moon’s " " 15′ 13″
Moon’s relative hourly motion in declination 5′ 44″ northward.
Right ascension, 29′ 33″ eastward.
Corrected for Jerusalem, 19′ 42″ eastward.
Altitude of the Gnomon, 34° 41′ 13″.
SUN’S ALTITUDE BEFORE AND AT NOON.
[Illustration: Phase at 20 minutes before noon.]
[Illustration: Phase at noon.]
We have now to consider “to what extent would a staircase rising at an
angle of 31° 47′ towards the Sun, with a gnomon so placed at the top as
to cast a shadow to the foot of the lower step on the shortest day of
the year be affected by a movement in a perpendicular direction of the
point of light to the extent of 23′, or ⅓ of a degree”? The effect would
be widely different at different times of the year, being greatest at
mid-winter when the shadows are longest, and least at mid-summer when
the shadows are shortest. It follows from this that January 13 being a
day but three weeks removed from mid-winter day the normal shadow would
be not far from its longest possible length, and the effect of a
displacement of 23′ would be neither more nor less than 1/12th of the
whole range of the steps whatever that range might have been. This
extent of motion, then, is fully sufficient to satisfy the condition
prescribed by the Biblical narrative of there being such a deflection of
the Sun’s light as would affect the shadow to the extent implied by the
words “ten steps” or “ten degrees,” which is virtually the same idea.
The same extent of motion could not have been produced under the same
conditions either a few days earlier or a few days later; that may
certainly be taken for granted. And the only point in which we are
necessarily in doubt arises from the fact that we are ignorant of the
actual number and nature of the graduations of Ahaz’s so-called “Dial.”
If it were permissible to assume that there were 120 graduations on the
instrument, be they steps properly so-called on a structure erected in
the open air or be they lines on a flat surface on some instrument
standing in a room, or what not, then the problem is solved, for 1/12
(as above) of 120 is ten—the “ten degrees” stated in the history.
As to whether the “dial” of Ahaz was a device built up of masonry in the
open air or was an instrument for indoor use we know absolutely nothing,
and speculation is useless. There is something to be said on both sides.
Bosanquet, on abstract grounds, leans to the latter view; on the other
hand he calls attention to the present existence in India, at Delhi and
Benares, of ruined Hindoo observatories in the form of huge masonry
sun-dials many yards in length and breadth and height.[33]
Finally it may be pointed out that there is some incidental confirmation
to be found for this Hezekiah incident having happened in winter. That
the season of the year was winter seems to be suggested by the word used
in the original Hebrew in connection with the return of the shadow.
“Backward” in Isaiah xxxviii. 8 might also be translated, “From the
end.” It would be very natural to hold that this implied that the motion
of the shadow was upwards from the _lower_ end of the group of steps
towards which the shadow had gone down. Now the lower end of the steps
could only have been the place of the shadow in December or January at
or near the time of the winter solstice. Moreover the mention of the
“lump of figs” seems to suggest the winter season. A cake of figs means
dried figs, not newly gathered summer figs.
Putting all the facts together we may fairly conclude that the
astronomical event which happened in connection with Hezekiah’s illness
was an eclipse of the Sun, and that its date was January 11, 689 B.C.
A few other Scripture passages need a passing mention. In Isaiah xiii.
10 we read:—
“The Sun shall be darkened in his going forth, and the Moon shall not
cause her light to shine.” It has been thought by Johnson that this
passage is an allusion to an eclipse of the Sun, and so it might be; but
on the other hand, it may be no more than one of those highly figurative
phrases which abound in holy Scripture, and of which the well-known
passage, “The stars in their courses fought against Sisera” (Judges v.
20), is a familiar example.
In Jeremiah x. 2 we read:—
“Be not dismayed at the signs of heaven; for the heathen are dismayed at
them.” This is cited as an eclipse allusion by Johnson, who points out
that the utterance of this caution preceded by about fifteen years the
celebrated eclipse of Thales (585 B.C.). But surely this is far-fetched.
I shall be inclined to attach the same criticism to his next citation.
Ezekiel employs these expressions:—“When I shall put thee out, I will
cover the heaven, and make the stars thereof dark; I will cover the Sun
with a cloud, and the Moon shall not give her light” (xxxii. 7). This
language resembles, in no small degree, Isaiah’s, already quoted, and,
like that, _might_ apply to the phenomenon of a solar eclipse, but
whether that was actually the prophet’s intention is another matter. He
may have witnessed the eclipse of 585 B.C. on the banks of the river
Chebar, and that spectacle may have put this imagery into his head.
Further than this it seems hardly safe to go.
This seems an appropriate place to mention a very interesting matter, to
which attention has been called by Oriental scholars in recent times,
who have investigated Assyrian and Egyptian monuments, and other
monuments of the same type. The story would be a long and interesting
one if presented in detail, and would far exceed my limits of space. I
must, therefore, be content with such a summary as that which has been
worked out by Mr. E. W. Maunder. Briefly the facts are these. There are
to be found in many places carvings in stone, symbolic of the Sun-god
once worshipped in the East. The general design, with of course
variations, is a circle with striated wings extending right and left to
two diameters of the wing, more or less, with a lesser extension in a
downward direction. Allowing for the roughness of the art, and for the
fact that the material was stone, it does not require any very great
stretch of imagination to see in these carvings the disc of a
totally-eclipsed Sun with, right and left and below it, that form of
corona which we have come to associate with total eclipses occurring at
periods of Sun-spot minima.[34] This idea should not seem far-fetched if
we bear in mind the fact that the ancient Orientals worshipped the Sun,
Moon, and Planets; and one of the natural outcomes of this is submitted
for our consideration by Maunder in the words following[35]:—
“There can be little doubt that the Sun was regarded partly as a symbol,
partly as a manifestation of the unseen, unapproachable Divinity. Its
light and heat, its power of calling into active exercise the
mysterious forces of germination and ripening, the universality of its
influence, all seemed the fit expressions of the yet greater powers
which belonged to the Invisible. What happened in a total solar eclipse?
For a short time that which seemed so perfect a divine symbol was
completely hidden. The light and heat, the two great forms of solar
energy, were withdrawn, but something took their place. A mysterious
light of mysterious form, unlike any other light, unlike any other
single form, was seen in its place. Could they fail to see in this a
closer, a more intimate revelation, a more exalted symbolism of the
Divine Nature and Presence? Just as in the various Greek ‘mysteries’ the
student was gradually advanced from one set of symbols to another even
more abstruse and esoteric, so here, on the broad face of heaven itself,
vouchsafed for a brief space of time and at long intervals apart, the
Deity revealed Himself to the initiated by a higher and more difficult
symbol than ordinarily. The symbol would vary in shape. We may take it
for granted that the old Chaldeans, as modern astronomers to-day, had at
one time or another presented to them every type of Coronal structure.
But there would, no doubt, be a difficulty in grasping or remembering
the irregular details of the Corona as seen in most eclipses. It
occasionally happens, however, that the Corona shows itself under a form
of grand and striking simplicity. It is now widely recognised that the
typical Corona of the minimum of the Sun-spot cycle consists chiefly of
two great equatorial streamers.”
Maunder then goes on to cite certain American pictures by Trouvelot and
others of the eclipse of July 29, 1878, in which the great extension of
the Corona to the East and the West is specially shown. One drawing in
particular, by Miss K. E. Wolcott, exhibits the Sun with a perfect
bright ring round it from which the Coronal streamers emanate in the
directions mentioned. Maunder then remarks that he has a strong
conviction that it was a Corona of this type which was the origin of the
“Ring with Wings,” the symbol which on Assyrian monuments is always
shown as floating over the head of the ring which is designed to
indicate the presence and protection of the Deity. In the article cited
he gives illustrations of two forms under which the “Ring with Wings”
appears on Assyrian and Egyptian monuments respectively, remarking that
“Egyptians too were Astronomers and Sun-worshippers and were experts in
the language of symbols. Equally with the Chaldeans the Egyptian priests
should have regarded the Corona as a symbolical revelation of the Deity
whose usual manifestation they recognised in the Sun, and accordingly we
find them employing a symbol which is almost as perfect a representation
of the Corona of minimum as that which the Assyrians adopted.” Another
curious point commented upon by Maunder is that the Assyrians frequently
insert the figure of their Deity within the ring, and attach thereto a
kilt-like dress. Even when they show the ring without the figure the
“kilt,” as it may be called, is still there, indicating that it is not
simply a garment worn by the figure, but an integral part of the
symbol. This “kilt” is represented as pleated, and the resemblance of
the pleatings to the polar rays shown in Trouvelot’s drawing of the
Corona, is “practically perfect.” On this point Maunder adds:—“If this
be a mere chance coincidence, it seems to me a most extraordinary one.”
He concludes by saying that these symbols, so frequently met with, and
so clearly designed to indicate the presence of the Deity, “are, in
their origin, drawings of the solar Corona, as seen at the Sun-spot
minimum, and as such are the earliest eclipse representations which have
been preserved to us.”
I give these ideas for what they are worth; they are very ingeniously
worked out, and though the argument is not conclusive, yet I do think
that there is enough in it to be worth attention.
FOOTNOTES:
[Footnote 23: Less certain is the allusion in Amos v. 8:—“Seek him
that ... maketh the day dark with night.”]
[Footnote 24: _Annales_, A.M., 3213, p. 45. Folio Ed.]
[Footnote 25: _Minor Prophets_, p. 217.]
[Footnote 26: _Athenæum_, May 18, 1867.]
[Footnote 27: After all, do the circumstances necessarily presuppose
a “miracle”? Hezekiah had only asked for a “sign.” In 2 Chron.
xxxii. 31 the word “wonder” is applied to the event.]
[Footnote 28: Hence the word “Tropic,” from τρέπω (I turn).]
[Footnote 29: Homer, _Odyssey_, vol. ii. p. 255. Clarendon Press
Series.]
[Footnote 30: _Life of Pherecydes_, sec. 6.]
[Footnote 31: _Life of Anaximander_, sec. 3.]
[Footnote 32: Du Halde’s “_China_,” 3rd edition, 1741, vol. iii.
p. 86.]
[Footnote 33: Paper by W. Hunter in _Asiatic Researches_, vol. v.,
p. 190. The Benares Observatory is described by Sir R. Barker in
_Phil. Trans._, vol. lxvii., p. 598. 1777.]
[Footnote 34: See p. 70 (_ante_).]
[Footnote 35: _Knowledge_, vol. xx., p. 9, January 1897.]
CHAPTER X.
ECLIPSES OF THE SUN MENTIONED IN HISTORY—CLASSICAL.
In this chapter we shall, for the most part, be on firmer ground than
hitherto, because several of the most eminent Greek and Latin historians
have left on record full and circumstantial accounts of eclipses which
have come under their notice, and which have been more or less
completely verified by the computations and researches of astronomers in
modern times. But these remarks do not, however, quite apply to the
first eclipse which will be mentioned.
Plutarch, in his _Life of Romulus_, refers to some remarkable incident
connected, in point of time at any rate, with his death:—“The air on
that occasion was suddenly convulsed and altered in a wonderful manner,
for the light of the Sun failed, and they were involved in an
astonishing darkness, attended on every side with dreadful thunderings
and tempestuous winds.” This so-called darkness is considered to have
been the same as that mentioned by Cicero.[36] There is so much myth
about Romulus that it is not safe to write in confident language.
Nevertheless it is a fact, according to Johnson, that there was a very
large eclipse of the Sun visible at Rome in the afternoon of May 26, 715
B.C., and 715 B.C. is supposed to have been the year, or about the year,
of the death of Romulus. Plutarch is also responsible for the statement
that a great eclipse of the Sun took place sometime before the birth of
Romulus; and if there is anything in this statement Johnson thinks that
the annular eclipse of November 28, 771 B.C., might meet the
circumstances of the case, but too much romance attaches to the history
of Romulus for anyone to write with assurance respecting the
circumstances of his career. Much of it is generally considered to be
fabulous.
In one of the extant fragments of the Greek poet Archilochus (said to be
the first who introduced iambics into his verses), the following
sentence occurs:—“Zeus the father of the Olympic Gods turned mid-day
into night hiding the light of the dazzling sun; an overwhelming dread
fell upon men.” The poet’s language may evidently apply to a total
eclipse of the Sun; and investigations by Oppolzer and Millosevich make
it probable that the reference is to the total eclipse of the Sun which
happened on April 6, 648 B.C. This was total at about 10 a.m. at Thasos
and in the northern part of the Ægean Sea. The acceptance of this date
displaces by about half a century the date commonly assigned for the
poet’s career, but this is not thought to be of much account having
regard to the hazy character of Grecian chronology before the Persian
wars.[37]
On May 28, 585 B.C. there occurred an eclipse the surrounding
circumstances of which present several features of particular interest.
One of the most celebrated of the astronomers of antiquity was Thales of
Miletus, and his astronomical labours were said to have included a
prediction of this eclipse, which moreover has the further interest to
us that it has assisted chronologists and historians in fixing the
precise date of an important event in ancient history. Herodotus[38]
describing a war which had been going on for some years between the
Lydians and the Medes gives the following account of the circumstances
which led to its premature termination:—“As the balance had not inclined
in favour of either nation, another engagement took place in the sixth
year of the war, in the course of which, just as the battle was growing
warm, day was suddenly turned into night. This event had been foretold
to the Ionians by Thales of Miletus, who predicted for it the very year
in which it actually took place. When the Lydians and Medes observed the
change they ceased fighting, and were alike anxious to conclude peace.”
Peace was accordingly agreed upon and cemented by a twofold marriage.
“For (says the historian) without some strong bond, there is little
security to be found in men’s covenants.” The exact date of this eclipse
was long a matter of discussion, and eclipses which occurred in 610 B.C.
and 593 B.C. were each thought at one time or another to have been the
one referred to. The question was finally settled by the late Sir G. B.
Airy, after an exhaustive inquiry, in favour of the eclipse of 585 B.C.
This date has the further advantage of harmonising certain statements
made by Cicero and Pliny as to its having happened in the 4th year of
the 48th Olympiad.
Another word or two may be interesting as regards the share which Thales
is supposed to have had in predicting this eclipse, the more so, that
very high authorities in the domains of astronomy, and chronology, and
antiquities take opposite sides in the matter. Sir G. C. Lewis, Bart.,
M.P., may be cited first as one of the unbelievers. He says[39] that
Thales is “reported to have predicted it to the _Ionians_. If he had
predicted it to the Lydians, in whose country the eclipse was to be
total, his conduct would be intelligible, but it seems strange that he
should have predicted it to the Ionians who had no direct interest in
the event.” Bosanquet replies to this by pointing out that Miletus, in
_Ionia_, was the birthplace of Thales, and also that a shadow, covering
two degrees of latitude, passing through Ionia, would also necessarily
cover Lydia.
Another dissentient is Sir H. C. Rawlinson,[40] who, remembering that
Thales is said to have predicted a good olive crop, and Anaxagoras the
fall of an aërolite, says:—“The prediction of this eclipse by Thales may
fairly be classed with the prediction of a good olive crop, or the fall
of an aërolite. Thales, indeed, could only have obtained the requisite
knowledge for predicting eclipses from the Chaldeans; and that the
science of these astronomers, although sufficient for the investigation
of lunar eclipses, did not enable them to calculate solar
eclipses—dependent as such a calculation is, not only on the
determination of the period of recurrence, but on the true projection
also of the track of the Sun’s shadow along a particular line over the
surface of the earth—may be inferred from our finding that in the
astronomical canon of Ptolemy, which was compiled from the Chaldean
registers, the observations of the Moon’s eclipse are alone entered.”
Airy[41] replied to these observations as follows:—“I think it not at
all improbable that the eclipse was so predicted, and there is one easy
way, and only one of predicting it—namely, by the _Saros_, or period of
18 years, 10 days, 8 hours nearly. By use of this period an evening
eclipse may be predicted from a morning eclipse but a morning eclipse
can rarely be predicted from an evening eclipse (as the interval of
eight hours after an evening eclipse will generally throw the eclipse at
the end of the _Saros_ into the hours of night). The evening eclipse,
therefore, of B.C. 585, May 28, which I adopt as being most certainly
the eclipse of Thales, might be predicted from the morning eclipse of
B.C. 603, May 17.... No other of the eclipses discussed by Baily and
Oltmanns present the same facility for prediction.”
Xenophon[42] mentions an eclipse as having led to the capture by the
Persians of the Median city Larissa. In the retreat of the Greeks on the
eastern side of the Tigris, they crossed the river Zapetes and also a
ravine, and then reached the Tigris. According to Xenophon, they found
at this place a large deserted city formerly inhabited by the Medes. Its
wall was 25 feet thick and 100 feet high; its circumference 2 parasangs
[= 7½ miles]. It was built of burnt brick on an under structure of
stone 20 feet in height. Xenophon then proceeds to say that “when the
Persians obtained the Empire from the Medes, the King of the Persians
besieged the city but was unable by any means to take it till a cloud
having covered the Sun and caused it to disappear completely, the
inhabitants withdrew in alarm, and thus the city was captured. Close to
this city was a pyramid of stone, one plethrum in breadth, two plethra
in height.... Thence the Greeks proceeded six parasangs to a great
deserted castle by a city called Mespila formerly inhabited by the
Medes; the substructure of its wall was of squared stone abounding in
shells ... the King of the Persians besieged it but could not take it;
Zeus terrified the inhabitants with thunderbolts, and so the city was
taken.”
The minute description here given by Xenophon enabled Sir A. H. Layard,
Captain Felix Jones, and others, to identify Larissa with the modern
Nimrud and Mespila with Mosul. A suspicion is thrown out in some
editions of the _Anabasis_ that the language cited might refer to an
eclipse of the Sun. It is to be noted, however, that it is not included
by Ricciolus in the list of eclipses mentioned in ancient writers which
he gives in his _Almagestum Novum_. Sir G. B. Airy, having had his
attention called to the matter, examined roughly all the eclipses which
occurred during a period of 40 years, covering the supposed date implied
by Xenophon. Having selected two, he computed them accurately but found
them inapplicable. He then tried another (May 19, 557 B.C.) which he had
previously passed over because he doubted its totality, and he had the
great satisfaction of finding that the eclipse, though giving a small
shadow, had been total, and that it had passed so near to Nimrud that
there could be no doubt of its being the eclipse sought.
Sir G. B. Airy was such a very careful worker and investigator of
eclipses that his conclusions in this matter have met with general
acceptance. It must, however, in fairness be stated that a very
competent American astronomer, Professor Newcomb, has expressed doubts
as to whether after all Xenophon’s allusion is to an eclipse, but,
judging by his closing words, the learned American does not seem quite
satisfied with his own scepticism, for he says—“Notwithstanding my want
of confidence, I conceive the possibility of a real eclipse to be
greater than in the eclipse of Thales, while we have the great
advantages that the point of occurrence is well defined, the shadow
narrow, and, if it was an eclipse at all, the circumstance of totality
placed beyond serious doubt.”[43]
In the same year as that in which, according to the common account, the
battle of Salamis was fought (480 B.C.), there occurred a phenomenon
which is thus adverted to by Herodotus[44]—“At the first approach of
Spring the army quitted Sardis and marched towards Abydos; at the moment
of its departure the Sun suddenly quitted its place in the heavens and
disappeared though there were no clouds in sight and the day was quite
clear; day was thus turned into night.” We are told[45] that “As the
king was going against Greece, and had come into the region of the
Hellespont, there happened an eclipse of the Sun in the East; this sign
portended to him his defeat, for the Sun was eclipsed in the region of
its rising, and Xerxes was also marching from that quarter.” So far as
words go these accounts admirably befit a total eclipse of the Sun, but
regarded as such it has given great trouble to chronologers, and the
identification of the eclipse is still uncertain. Hind’s theory is that
the allusion is to an eclipse and in particular to the eclipse of
February 17, 478 B.C. Though not total at Sardis yet the eclipse was
very large, 94/100ths of the Sun being covered. If we accept this, it
follows that the usually recognised date for the battle of Salamis must
be altered by two years. Airy thought it “extremely probable” that the
narrative related to the total eclipse of the _Moon_, which happened on
March 13, 479 B.C., but this is difficult to accept, especially as
Plutarch, in his _Life of Pelopidas_, says—“An army was soon got ready,
but as the general was on the point of marching, the Sun began to be
eclipsed, and the city was covered with darkness in the daytime.” This
seems explicit enough, assuming the record to be true and that the same
incident is referred to by Plutarch as by Herodotus and Aristides.
Since the time when Airy and Hind examined this question, all the known
facts have been again reviewed by Mr. W. T. Lynn, who pronounces, but
with some hesitation, in favour of the eclipse of October 2, 480 B.C.,
as the one associated with the battle of Salamis. He does this by
refusing to see in the above quotations from Herodotus any allusion to a
solar eclipse at all, but invites us to consider a later statement in
Herodotus[46] as relating to an eclipse though the historian only calls
it a prodigy.
After the battle of Thermopylæ the Peloponnesian Greeks commenced to
fortify the isthmus of Corinth with the view of defending it with their
small army against the invading host of Xerxes. The Spartan troops were
under the command of Cleombrotus, the brother of Leonidas, the hero of
Thermopylæ. He had been consulting the oracles at Sparta, and Herodotus
states that “while he was offering sacrifice to know if he should march
out against the Persian, the Sun was suddenly darkened in mid-sky.” This
occurrence so frightened Cleombrotus that he drew off his forces and
returned home. It is uncertain from the narrative of Herodotus whether
Cleombrotus returned to Sparta in the autumn of the year of the battle
of Salamis, or in the spring of the next following year which was that
in which the battle of Platæa was fought. Bishop Thirlwall[47] thinks
that it was the latter, but Lynn pronounces for the former, adding that
the date may well have been in October, and the solar eclipse of October
2, 480 B.C. may have been the phenomenon which attracted notice,
particularly as the Sun would have been high in the heavens, the
greatest phase (6/10ths) occurring, according to Hind, at 50 minutes
past noon. Here I must leave the matter, merely remarking that this
alternative explanation obviates the necessity for disturbing the
commonly received date of the battle of Salamis.
Thucydides states that during the Peloponnesian war “things formerly
repeated on hearsay, but very rarely confirmed by facts, became not
incredible, both about earthquakes and eclipses of the Sun which came to
pass more frequently than had been remembered in former times.” One such
eclipse he assigns to the first year of the war and says[48] that “in
the same summer, at the beginning of a new lunar month (at which time
alone the phenomenon seems possible) the Sun was eclipsed after mid-day,
and became full again after it had assumed a crescent form and after
some of the stars had shone out.” Aug. 3, 431 B.C. is generally
recognised as the date of this event. The eclipse was not total only
three-fourths of the Sun’s disc being obscured. Venus was 20° and
Jupiter 43° distant from the Sun, so probably these were the “stars”
that were seen. This eclipse nearly prevented the Athenian expedition
against the Lacedæmonians. The sailors were frightened by it, but a
happy thought occurred to Pericles, the commander of the Athenian
forces. Plutarch, in his _Life of Pericles_, says:—“The whole fleet was
in readiness, and Pericles on board his own galley, when there happened
an eclipse of the Sun. The sudden darkness was looked upon as an
unfavourable omen, and threw the sailors into the greatest
consternation. Pericles observing that the pilot was much astonished and
perplexed, took his cloak, and having covered his eyes with it, asked
him if he found anything terrible in that, or considered it as a bad
presage? Upon his answering in the negative, he said, ‘Where is the
difference, then between this and the other, except that something
bigger than my cloak causes the eclipse?’”
Another eclipse is mentioned by Thucydides[49] in connection with an
expedition of the Athenians against Cythera. He says:—“At the very
commencement of the following summer there was an eclipse of the Sun at
the time of a new moon, and in the early part of the same month an
earthquake.” This has been identified with the annular eclipse of March
21, 424 B.C., the central line of which passed across Northern Europe.
It is not quite clear whether the historian wishes to insinuate that the
eclipse caused the earthquake or the earthquake the eclipse.
An eclipse known as that of Ennius is another of the eclipses antecedent
to the Christian Era which has been the subject of full modern
investigation, and the circumstances of which are such that, in the
language of Professor Hansen, “it may be reckoned as one of the most
certain and well-established eclipses of antiquity.” The record of it
has only been brought to light in modern times by the discovery of
Cicero’s Treatise, _De Republicâ_. According to Cicero,[50] Ennius the
great Roman poet, who lived in the second century B.C., and who died of
gout contracted, it is said, by frequent intoxication, recorded an
interesting event in the following words:—_Nonis Junii soli luna
obstetit et nox_, “On the Nones of June the Moon was in opposition to
the Sun and night.” This singular phrase has long been assumed to allude
to an eclipse of the Sun, but the precise interpretation of the words
was not for a long time realised. In Cicero’s time the Nones of June
fell on the 5th, but in the time of Ennius, who lived a century and a
half before Cicero, the Nones of June fell between June 5 and July 4 on
account of the lunar years and the intercalary month of the Roman
Calendar. The date of this eclipse is distinctly known to be June 21,
400 B.C., but the hour was long in dispute. Professor Zech found that
the Sun set at Rome eclipsed, and that the maximum phase took place
after sun-set. Hansen, however, with his better Tables, found that the
eclipse was total at Rome, and that the totality ended at 7.33 p.m., the
Sun setting almost immediately afterwards at 7.36. This fact, Hansen
considers, explains the otherwise unintelligible passage of Ennius
quoted above: instead of saying _et nox_, he should have said _et simul
nox_, “and immediately it was night.” Newcomb questions the totality of
this eclipse, but assigns no clear reasons for his doubts.[51]
On August 14, 394 B.C., there was a large eclipse of the Sun visible in
the Mediterranean. It occurred in the forenoon, and is mentioned by
Xenophon[52] in connection with a naval engagement in which the Persians
were defeated by Conon.
Plutarch, in his _Life of Pelopidas_, relates how one, Alexander of
Pheræ, had devastated several cities of Thessaly, and that as soon as
the oppressed inhabitants had learned that Pelopidas had come back from
an embassy on which he had been to the King of Persia, they sent
deputies to him to Thebes to beg the favour of armed assistance, with
Pelopidas as general. “The Thebans willingly granted their request, and
an army was soon got ready, but as the general was on the point of
marching, the Sun began to be eclipsed, and the city was covered with
darkness in the day-time.” This eclipse is generally identified with
that of July 13, 364 B.C. If this is correct, Plutarch’s language must
be incorrect, or at least greatly exaggerated, for no more than about
three-fourths of the Sun was obscured.
On February 29, 357 B.C., there happened an eclipse, also visible in or
near the Mediterranean. This is supposed to have been the eclipse for
the prediction of which Helicon, a friend of Plato, received from
Dionysius, King of Syracuse, payment in the shape of a talent.
We have now to consider another ancient eclipse which has a history of
peculiar interest as regards the investigations to which it has been
subjected. It is commonly known as the “Eclipse of Agathocles,” and is
recorded by two historians of antiquity in the words following. Diodorus
Siculus[53] says:—
“Agathocles also, though closely pursued by the enemy, by the advantage
of the night coming on (beyond all hope), got safe off from them. The
next day there was such an eclipse of the Sun, that the stars appeared
everywhere in the firmament, and the day was turned into night, upon
which Agathocles’s soldiers (conceiving that God thereby did foretell
their destruction) fell into great perplexities and discontents
concerning what was like to befall them.”
Justin says[54]:—
“By the harangue the hearts of the soldiers were somewhat elevated, but
an eclipse of the Sun that had happened during their voyage still
possessed them with superstitious fears of a bad omen. The king was at
no less pain to satisfy them about this affair than about the war, and
therefore he told them that he should have thought this sign an ill
presage for them, if it had happened before they set out, but having
happened afterwards he could not but think it presaged ill to those
against whom they marched. Besides, eclipses of the luminaries always
signify a change of affairs, and therefore some change was certainly
signified, either to Carthage, which was in such a flourishing
condition, or to them whose affairs were in a very ruinous state.”
The substance of these statements is that in the year 310 B.C.
Agathocles, Tyrant of Syracuse, while conducting his fleet from Syracuse
to the Coast of Africa, found himself enveloped in the shadow of an
eclipse, which evidently, from the accounts, was total. His fleet had
been chased by the Carthaginians on leaving Syracuse the preceding day,
but got away under the cover of night. On the following morning about 8
or 9 a.m. a sudden darkness came on which greatly alarmed the sailors.
So considerable was the darkness, that numerous stars appeared. It is
not at the first easy to localise the position of the fleet, except that
we may infer that it could hardly have got more than 80 or at the most
100 miles away from the harbour of Syracuse where it had been closely
blockaded by a Carthaginian fleet. Agathocles would not have got away at
all but for the fact that a relieving fleet was expected, and the
Carthaginians were obliged to relax their blockade in order to go in
search of the relieving fleet. Thus it came about not only that
Agathocles set himself free, but was able to retaliate on his enemies by
landing on the coast of Africa at a point near the modern Cape Bon, and
devastating the Carthaginian territories. The voyage thither occupied
six days, and the eclipse occurred on the second day. Though we are not
informed of the route followed by Agathocles, that is to say whether he
passed round the North or the South side of the island of Sicily, yet it
has been made clear by astronomers that the southern side was that
taken.
Baily, who was the first modern astronomer to investigate the
circumstances of this eclipse, found that there was an irreconcilable
difference between the path of the shadow found by himself and the
historical statement, a gap of about 180 geographical miles seeming to
intervene between the most southerly position which could be assigned to
the fleet of Agathocles, and the most northerly possible limit of the
path of the eclipse shadow. This was the condition of the problem when
Sir G. B. Airy took it up in 1853.[55] He, however, was able to throw an
entirely new light upon the matter. The tables used by Baily were
distinctly inferior to those now in use, and Sir G. B. Airy thought
himself justified in saying that to obviate the discordance of 180 miles
just referred to “it is only necessary to suppose an error of 3′ in the
computed distances of the Sun and Moon at conjunction, a very
inconsiderable correction for a date anterior to the epoch of the tables
by more than twenty-one centuries.”
It deserves to be mentioned, though the point cannot here be dwelt upon
at much length, that these ancient eclipses all hang together in such a
way that it is not sufficient for the man of Astronomy and the man of
Chronology to agree on one eclipse, unless they can harmonise the facts
of several.
For instance, the eclipse of Thales, the date of which was long and much
disputed, has a material bearing on the eclipse of Agathocles, the date
of which admits of no dispute; and one of the problems which had to be
solved half a century ago was how best to use the eclipse of Agathocles
to determine the date of that of Thales. If 610 B.C. were accepted for
the Thales eclipse, so as to throw the zone of total darkness anywhere
over Asia Minor (where for the sake of history it was essential to put
it) the consequence would be that the shadow of the eclipse of 310 B.C.
would have been thrown so far on to land, in Africa, as to make it out
of the question for Agathocles and his fleet to have been in it, yet we
know for a certainty that he was in it in that year, and no other year.
Conversely, if 603 B.C. were accepted for the Thales eclipse, then to
raise northwards the position of the shadow in that year from the line
of the Red Sea and the Persian Gulf, that it might pass through Asia
Minor, would so raise the position of the shadow in 310 B.C. as to throw
it far too much to the N. of Sicily for Agathocles, who we know must
have gone southwards to Africa, to have entered it. But if we assume 585
B.C. as the date of the eclipse of Thales, we obtain a perfect
reconciliation of everything that needs to be reconciled; the shadow of
the eclipse of 585 B.C. will be found to have passed where ancient
history tells us it did pass—namely, through Ionia, and therefore
through the centre of Asia Minor, and on the direct route from Lydia to
Media; whilst we also find that the shadow of the 310 B.C. eclipse, that
is the one in the time of Agathocles, passed within 100 miles of
Syracuse, a fact which is stated almost in those very words by the two
historians who have recorded the doings of Agathocles and his fleet in
those years.
This is where the matter was left by Airy in 1853. Four years later the
new solar and lunar tables of the German astronomer Hansen were
published, and having been applied to the eclipse of 585 B.C., the
conclusions just stated were amply confirmed. As if to make assurance
doubly sure, Airy went over his ground again, testing his former
conclusions with regard to the eclipse of Thales by the eclipse of
Larissa, in 557 B.C. already referred to, and bringing in the eclipse
of Stiklastad in 1030 A.D., to be referred to presently. And as the
final result, it may be stated that all the foregoing dates are now
known to an absolute certainty, especially confirmed as they were in all
essential points by a computer of the eminence of the late Mr. J. R.
Hind.
On a date which corresponds to February 11, 218 or 217 B.C., an eclipse
of the Sun, which was partial in Italy, is mentioned by Livy.[56]
Newcomb found that the central line passed a long way from Italy, to
wit, “far down in Africa.”
An eclipse of the Sun is mentioned by Dion Cassius[57] as having
happened when Cæsar crossed the Rubicon, a celebrated event made use of
by speakers, political and otherwise, on endless occasions in modern
history. There seems no doubt that the passage of the Rubicon took place
in 51 B.C., and that the eclipse must have been that of March 7, 51 B.C.
The circumstances of this eclipse have been investigated by Hind, who
found that the eclipse was an annular one, the annular phase lasting 6½
minutes in Northern Italy.
Arago associates the death of Julius Cæsar in 44 B.C. with an annular
eclipse of the Sun, but seemingly without sufficient warrant. The actual
record is to the effect that about the time of the great warrior’s death
there was an extraordinary dimness of the Sun. Whatever it was that was
noticed, clearly it could not have been an annular eclipse, because no
such eclipse then happened. Johnson suggests that Arago confused the
record of some meteorological interference with the Sun’s light with the
annular eclipse that happened seven years previously when Cæsar passed
the Rubicon, to which eclipse allusion has already been made. That there
was for a long while a great deficiency of sunshine in Italy about the
time of Cæsar’s death seems clear from remarks made by Pliny, Plutarch,
and Tibullus, and the words of Suetonius seem to imply something of a
meteorological character. I should not have mentioned this matter at
all, but for Arago’s high repute as an astronomer. According to
Seneca[58] during an eclipse a comet was also seen.
It is an interesting question to inquire whether any allusions to
eclipses are to be found in Homer, and no very certain answer can be
given. In the _Iliad_ (book xvii., lines 366-8) the following passage
will be found:—“Nor would you say that the Sun was safe, or the Moon,
for they were wrapt in dark haze in the course of the combat.”
In the _Odyssey_ (book xx., lines 356-7) we find:—“And the Sun has
utterly perished from heaven and an evil gloom is overspread.” This was
considered by old commentators to be an allusion to an eclipse, and in
the opinion of W. W. Merry[59] “this is not impossible, as they were
celebrating the Festival of the New Moon.”
Certainly this language has somewhat the savour of a total eclipse of
the Sun, but it is difficult to say whether the allusion is historic,
as of a fact that had happened, or only a vague generality. Perhaps the
latter is the most justifiable surmise.
I have in the many preceding pages been citing ancient eclipses, for the
reason, more or less plainly expressed, that they are of value to
astronomers as assisting to define the theory of the Moon’s motions in
its orbit, and this they should do; but it is not unreasonable to bring
this chapter to a close by giving the views of an eminent American
astronomer as to the objections to placing too much reliance on ancient
accounts of eclipses. Says Prof. S. Newcomb[60]:—“The first difficulty
is to be reasonably sure that a total eclipse was really the phenomenon
observed. Many of the statements supposed to refer to total eclipses are
so vague that they may be referred to other less rare phenomena. It must
never be forgotten that we are dealing with an age when accurate
observations and descriptions of natural phenomena were unknown, and
when mankind was subject to be imposed upon by imaginary wonders and
prodigies. The circumstance which we should regard as most unequivocally
marking a total eclipse is the visibility of the stars during the
darkness. But even this can scarcely be regarded as conclusive, because
Venus may be seen when there is no eclipse, and may be quite conspicuous
in an annular or a considerable partial eclipse. The exaggeration of a
single object into a plural is in general very easy. Another difficulty
is to be sure of the locality where the eclipse was total. It is
commonly assumed that the description necessarily refers to something
seen where the writer flourished, or where he locates his story. It
seems to me that this cannot be safely done unless the statement is made
in connection with some battle or military movement, in which case we
may presume the phenomena to have been seen by the army.”
FOOTNOTES:
[Footnote 36: _De Republicâ_, Lib. vi., cap. 22.]
[Footnote 37: E. Millosevich, _Memorie della Societa Spettroscopisti
Italiani_, vol. xxii. p. 70. 1893.]
[Footnote 38: _Herodotus_, Book i., chap. 74. This eclipse is also
mentioned by Pliny (_Nat. Hist._, Book ii., chap. 9) and by Cicero
(_De Divinatione_, cap. 49).]
[Footnote 39: _Astronomy of the Ancients_, p. 88.]
[Footnote 40: _Herodotus_, edited by Rev. G. Rawlinson, vol. i. p.
212.]
[Footnote 41: _Month. Not._, R.A.S., vol. xviii. p. 148; March
1858.]
[Footnote 42: _Anabasis_, Lib. iii., cap. 4, sec. 7.]
[Footnote 43: _Washington Observations_, 1875, Appendix II., p. 31.]
[Footnote 44: Book vii., chap. 37. See Rawlinson’s _Herodotus_, vol.
iv. p. 39.]
[Footnote 45: _Scholia, in Aristidis Orationes_, Ed. Frommel, p.
222.]
[Footnote 46: Book ix., chap. 10. See Rawlinson’s _Herodotus_, 3rd
ed. vol. iv. p. 379.]
[Footnote 47: _History of Greece_, vol. ii. p. 330.]
[Footnote 48: Book ii., chap. 28.]
[Footnote 49: Book iv., chap. 52.]
[Footnote 50: _De Republicâ_, Lib. i. c. 16.]
[Footnote 51: _Washington Observations_, 1875, Appendix II., p. 33.]
[Footnote 52: _Hellenics_, Book iv., chap. 3, sec. 10.]
[Footnote 53: _Bibliothecæ Historicæ_, Lib. xx., cap. 1, sec. 5.]
[Footnote 54: _Historia_, Lib. xxii., cap. 6.]
[Footnote 55: _Phil. Trans._, vol. cxliii. pp. 187-91, 1853.]
[Footnote 56: _Hist. Rom._, Lib. xxii., cap. 1.]
[Footnote 57: _Hist. Rome_, Book xli., chap. 14.]
[Footnote 58: _Naturalium Questionum_, Lib. vii.]
[Footnote 59: Homer, _Odyssey_, vol. ii. p. 328. Clarendon Press
Series.]
[Footnote 60: _Washington Observations_, 1875, Appendix II., p. 18.]
CHAPTER XI.
ECLIPSES OF THE SUN MENTIONED IN HISTORY.—
THE CHRISTIAN ERA TO THE NORMAN CONQUEST.
The Christian Era is, for several reasons, a suitable point of time from
which to take a new departure in speaking of historical eclipses,
although the First Century, at least, might obviously be regarded as
belonging to classical history—but let that pass.
Dion Cassius[61] relates that on a date corresponding to March 28, A.D.
5, the Sun was partly eclipsed. Johnston says that the central line
passed over Norway and Sweden. It seems, perhaps, a little strange that
a writer who lived in Bithynia in the 3rd Century of the Christian Era
should have picked up any information about something that happened in
the extreme North of Europe two centuries previously. But probably the
eclipse must have been seen in Italy.
On November 24, A.D. 29, there happened an eclipse of the Sun which is
sometimes spoken of as the “eclipse of Phlegon.” Eusebius, the
ecclesiastical historian, records Phlegon’s testimony. Phlegon was a
native of Tralles in Lydia, and one of the Emperor Adrian’s freedmen.
The eclipse in question happened at noon, and the stars were seen. It
was total, and the line of totality, according to Hind,[62] passed
across the Black Sea from near Odessa to Sinope, thence near the site of
Nineveh to the Persian Gulf. A partial eclipse with four-fifths of the
Sun’s diameter covered was visible at Jerusalem. This is the only solar
eclipse which was visible at Jerusalem during the period usually fixed
for Christ’s public ministry. This eclipse was for a long time, and by
various writers, associated with the darkness which prevailed at
Jerusalem on the day of our Lord’s Crucifixion, but there seems no
warrant whatever for associating the two events. The Crucifixion
darkness was assuredly a supernatural phenomenon, and there is nothing
supernatural in a total eclipse of the Sun. To this it may be added that
both Tertullian at the beginning of the 3rd century and Lucian, the
martyr of Nicomedia, who died in 312, appealed to the testimony of
national archives then in existence, as witnessing to the fact that a
supernatural darkness had prevailed at the time of Christ’s death.
Moreover, the generally recorded date of the Crucifixion, namely, April
3, A.D. 33, would coincide with a full Moon. As it happened, that full
Moon suffered eclipse, but she emerged from the Earth’s shadow about a
quarter of an hour before she rose at Jerusalem (6 h. 36 m. p.m.): the
penumbra continued upon her disc for an hour afterwards.
Speaking of the Emperor Claudius, Dion Cassius[63] says:—“There was
going to be an eclipse on his birthday. Claudius feared some
disturbance, as there had been other prodigies, so he put forth a public
notice, not only that the obscuration would take place and about the
time and magnitude of it, but also about the causes which produce such
events.” This is an interesting statement, especially in view of what I
have said on a previous page about the indifference of the Romans to
Astronomy. It would, likewise, be interesting to know how Claudius
acquired his knowledge, and who coached him up in the matter. This
eclipse occurred on August 1, A.D. 45. Barely half the Sun’s diameter
was covered.
Philostratus[64] states that “about this time while he was pursuing his
studies in Greece such an omen was observable in the heavens. A crown
resembling Iris surrounded the disc of the Sun and darkened its rays.”
“About this time” is to be understood as referring to some date shortly
preceding the death of the Emperor Domitian which occurred on September
18, A.D. 96. This has usually been regarded as the earliest allusion to
what we now call the Sun’s “Corona”; or, as an alternative idea, that
the allusion is simply to an annular eclipse of the Sun. But both these
theories have been called in question; by Johnston because he cannot
find an eclipse which in his view of things will respond as regards date
to the statement of Philostratus, and by Lynn on the same ground and on
other grounds, _more suo_. The question of identification requires
looking into more fully. There was a total eclipse on May 21, A.D. 95,
but it was only visible as a partial eclipse in Western Asia and not
visible at all in Greece. This is given as the conclusion arrived at by
the German astronomer Ginzel. But it does not seem to me sufficient to
overthrow, without further investigation, the fairly plain language of
Philostratus, which is possibly confirmed by a passage in Plutarch[65]
in which he discusses certain eclipse phenomena in the light of a recent
eclipse. The date of Plutarch’s “recent” eclipse is somewhat uncertain,
but that fact does not necessarily militate against his testimony
respecting the Corona or what is regarded to have been such. The
statement of Philostratus, treated as a mention of a total solar
eclipse, is accepted as sufficiently conclusive by Sir W. Huggins and
the late Professor R. Grant. Johnston, to meet the supposed difficulty
of finding an eclipse to accord with the assertion of the historian,
suggests that “perhaps some peculiar solar halo or mock Sun, or other
meteorological formation” is referred to. But Stockwell has advanced
very good reasons for the opinion that the eclipse of Sept. 3, A.D. 118,
fully meets the circumstances of the case. Grant’s opinion is given in
these emphatic words:—“It appears to me that the words here quoted
[from Apollonius] refer beyond all doubt to a total eclipse of the Sun,
and thus the phenomenon seen encompassing the Sun’s disc was, really as
well as verbally, identical with the modern Corona.”[66]
With the end of the first century of the Christian Era we may be said to
quit the realms of classical history and to pass on to eclipse records
of a different character, and, so far as regards European observations,
of comparatively small scientific value or usefulness. Our information
is largely derived from ecclesiastical historians and, later on, from
monkish chronicles, which as a rule are meagre in a surprising degree.
Perhaps I ought not to say “surprising,” because after the times of the
Greek astronomers (who in their way may almost be regarded as
professionals), and after the epoch of the famous Ptolemy, Astronomy
well-nigh ceased to exist for many centuries in Europe, until, say, the
15th century, barring the labours of the Arabians and their kinsmen the
Moors in Spain in the 9th and following centuries.
In examining therefore the records of eclipses which have been handed
down to us from A.D. 100 forwards through more than 1000 years, I shall
not offer my readers a long dry statement of eclipse dates, but only
pick out here and there such particular eclipses as seem to present
details of interest for some or other reason.
On April 12, 237 A.D., there was, according to Julius Capitolinus, an
eclipse of the Sun, so great “that people thought it was night, and
nothing could be done without lights.” Ricciolus remarked that this
eclipse happened about the time of the Sixth Persecution of the
Christians, and when the younger Gordian was proclaimed Emperor, after
his father had declined the proffered dignity, being 80 years of age.
The line of totality crossed Italy about 5 p.m. in the afternoon, to the
N. of Rome, and embraced Bologna.
Calvisius records, on the authority of Cedrenus, an eclipse of the Sun
on August 6, 324 A.D., which was sufficiently great for the stars to be
seen at mid-day. The eclipse was associated with an earthquake, which
shattered thirteen cities in Campania. Johnston remarks that no more
than three-fourths of the Sun’s disc would have been covered, as seen in
Campania, but that elsewhere in Italy, at about 3 p.m., the eclipse was
much larger, and perhaps one or two of the planets might have been
visible.
On July 17, 334 A.D., there was an eclipse, which seems to have been
total in Sicily, if we may judge from the description given by Julius
Firmicus.[67]
Ammianus Marcellinus[68] describes an eclipse, to which the date of
August 28, 360 A.D., has been assigned. Humboldt, quoting this
historian, says that the description is quite that of a solar eclipse,
but its stated long duration (daybreak to noon), and the word _caligo_
(fog or mist) are awkward factors. Moreover, the historian associates it
with events which happened in the eastern provinces of the Roman
Empire; but Johnston seems in effect to challenge Marcellinus’s
statement when he says, “It is true that there was an annular eclipse of
the Sun in the early morning on the above date, but it could only be
seen in countries E. of the Persian Gulf.”
About the time that Alaric, King of the Visigoths appeared before Rome,
there was a gloom so great that the stars appeared in the daytime. This
narrative is considered to apply to an eclipse of the Sun, which
occurred on June 18, 410 A.D. The eclipse was an annular one, but as the
central line must have crossed far S. of Rome, the stars must have been
seen not at Rome but somewhere else.
An eclipse occurred on July 19, 418 A.D., which is remarkable for a
twofold reason. People had an opportunity not only of seeing an eclipse,
but also a comet. We owe the account of the circumstances to
Philostorgius,[69] who tells us that—“On July 19, towards the 8th hour
of the day, the Sun was so eclipsed, that even the stars were visible.
But at the same time that the Sun was thus hid, a light, in the form of
a cone was seen in the sky; some ignorant people called it a comet, but
in this light we saw nothing that announced a comet, for it was not
terminated by a tail; it resembled the flame of a torch, subsisting by
itself, without any star for its base. Its movement too was very
different from that of a comet. It was first seen to the E. of the
equinoxes; after that, having passed through the last star in the Bear’s
tail, it continued slowly its journey towards the W. Having thus
traversed the heavens, it at length disappeared, having lasted more than
four months. It first appeared about the middle of the summer, and
remained visible until nearly the end of autumn.”
Boillot, a French writer, has suggested that this description is that of
the zodiacal light, but this seems out of the question in view of the
details given by the Chinese of a comet having been visible in the
autumn of this year for 11 weeks, and having passed through the square
of Ursa Major. Reverting to the eclipse—Johnston finds that the greatest
phase at Constantinople, which was probably the place of observation,
occurred at about half an hour after noon, when a thin crescent of light
might have been seen on the northern limb of the Sun. From this it would
appear that the central line of eclipse must have passed somewhat to the
south of Constantinople. To the same effect Hind, who found that
95/100ths of the Sun’s diameter was covered at Constantinople.
An eclipse of the Sun seems to be referred to by Gregorius Turonensis,
when he says[70] that:—“Then even the Sun appeared hideous, so that
scarcely a third part of it gave light, I believe on account of such
deeds of wickedness and shedding of innocent blood.” This would seem to
have been the eclipse which occurred on February 24, 453 A.D., when
Attila and the Huns were ravaging Italy, and to them it was doubtless
that the writer alluded. At Rome three-fourths of the Sun’s disc would
have been eclipsed at sunset, a finding which tallies fairly with the
statement of Gregorius.
It is not till far into the 6th century that we come upon a native
English record of an eclipse of the Sun as having been observed in
England. This deficiency in our national annals is thus judiciously
explained and commented on by our clever and talented American
authoress.[71] Speaking of the eclipse of February 15, 538 A.D., she
says:—“The accounts, however, are greatly confused and uncertain, as
would perhaps be natural fully 60 years before the advent of St.
Augustine, and when Britain was helplessly harassed with its continual
struggle in the fierce hands of West Saxons and East Saxons, of Picts
and conquering Angles. Men have little time to record celestial
happenings clearly, much less to indulge in scientific comment and
theorising upon natural phenomena, when the history of a nation sways to
and fro with the tide of battle, and what is gained to-day may be
fatally lost to-morrow. And so there is little said about this eclipse,
and that little is more vague and uncertain even than the monotonous
plaints of Gildas—the one writer whom Britain has left us, in his meagre
accounts of the conquest of Kent, and the forsaken walls and violated
shrines of this early epoch.”
The well-known _Anglo-Saxon Chronicle_[72] is our authority for this
eclipse having been noted in England, but the record is bare
indeed:—“In this year the Sun was eclipsed 14 days before the Calends of
March from early morning till 9 a.m.” Tycho Brahe, borrowing from
Calvisius, who borrowed from somebody else, says that the eclipse
happened “in the 5th year of Henry, King of the West Saxons, at the 1st
hour of the day till nearly the 3rd, or immediately after sunrise.”
Johnson finds that at London nearly three-fourths of the Sun’s disc was
covered at 7.43 a.m.
The next eclipse recorded in the _Anglo-Saxon Chronicle_ is somewhat
difficult to explain. It is said that in 540 A.D. “The Sun was eclipsed
on the 12th of the Calends of July [= June 20], and the stars appeared
full nigh half an hour after 9 a.m.” Johnson’s calculations make the
middle of the eclipse to have occurred at about 7.37 a.m. at London,
two-thirds of the Sun’s diameter being covered. He notes that the Moon’s
semi-diameter was nearly at its maximum whilst the Sun’s semi-diameter
was nearly at its minimum—a favourable combination for a long totality.
The visibility of the stars seems difficult to explain in connection
with this eclipse, and therefore he suggests that the annalist has made
a mistake of four years and meant to refer to the eclipse of September
1, 536 A.D., but this does not seem a satisfactory theory.
The year after Pope Martin held a Synod to condemn the Monothelite
heresy, an eclipse of the Sun took place. It is mentioned by Tycho Brahe
in his catalogue of eclipses as having been seen in England. Johnson
gives the date as February 6, 650 A.D., and finds that the Sun was
three-fourths obscured at London at 3.30 p.m.
The _Anglo-Saxon Chronicle_ tells us under the year A.D. 664 that, “In
this year the Sun was eclipsed on the 5th of the Nones of May; and
Earcenbryht, King of the Kentish people died and Ecgbryht his son
succeeded to the Kingdom.” Kepler thought this eclipse had been total in
England, and Johnson calculating for London found that on May 1, at 5
p.m., there would only have been a very thin crescent of the Sun left
uncovered on the southern limb, so that the line of totality would have
passed across the country some distance to the N. of London.
The eclipse of Dec. 7, A.D. 671, seems to be associated with a comic
tragedy. The Caliph Moawiyah had a fancy to remove Mahomet’s pulpit from
Medina to his own residence at Damascus. “He said that the walking-stick
and pulpit of the Apostle of God should not remain in the hands of the
murderers of Othman. Great search was made for the walking-stick, and at
last they found it. Then they went in obedience to his commands to
remove the pulpit, when immediately, to their great surprise and
astonishment, the Sun was eclipsed to that degree that the stars
appeared.”[73] Once again the question of visible stars is in some sense
a source of difficulty. Hind found that the eclipse was annular on the
central line. At Medina the greatest phase occurred at 10h. 43m. a.m.
when 85/100ths of the Sun’s diameter was obscured. Hind suggests that in
the clear skies of that part of the world such a degree of eclipse might
be sufficient to bring out the brighter planets or stars. At any rate no
larger eclipse visible at Medina occurred about this epoch. Prof. Ockley
seems to refer to this eclipse in making, on the authority of several
Arabian writers, the mention he does of an eclipse in the quotation just
given.
Perhaps this will be a convenient place to bring in some remarks on
certain Arabian observations of eclipses only made known to the
scientific world in modern times. That the Arabians were very capable
practical astronomers has long been recognised as a well-established
fact, and if it had not been for them there would have been a tremendous
blank in the history of astronomy during at least six centuries from
about the year A.D. 700 onwards. In the year 1804 there was published at
Paris a French translation of an Arabian manuscript preserved at the
University of Leyden of which little was known until near the end of the
last century. The manuscript was then sent to Paris on loan to the
French Government which caused a translation to be made by “Citizen”
Caussin, and this was published under the title of _Le Livre de la
grande Table Hakénate_.[74] Caussin was Professor of Arabic at the
College of France. Newcomb considers this to contain the earliest exact
astronomical observations of eclipses which have reached us. He remarks
that some of the data left us by Ptolemy, Theon, Albategnius and others
may be the results of actual observations, but in no case, so far as is
known, have the figures of the actual observations been handed down. For
example, we cannot regard “midnight” nor “the middle of an eclipse” as
moments capable of direct observation without instruments of precision;
but in the Arabian work under consideration we find definite statements
of the altitudes of the heavenly bodies at the moments of the beginning
and ending of eclipses—data not likely to be tampered with in order to
agree with the results of calculation. The eclipses recorded are 28 in
number and usually the beginning and end of them were observed. The
altitudes are given sometimes only in whole degrees, sometimes in coarse
fractions of a degree. The most serious source of error to be confronted
in turning these observations to account arises from the uncertainty as
to how long after the first contact the eclipse was perceived and the
altitude taken; and how long before the true end was the eclipse lost
sight of. Making the best use he could of the records available Newcomb
found that they could safely be employed in his investigations into the
theory of the Moon.
The observations were taken, some at Bagdad and the remainder at Cairo.
I do not propose to occupy space by transcribing the accounts in detail,
but one extract may be offered as a sample of the rest—“Eclipse of the
Sun observed at Bagdad, August 18, 928 A.D. The Sun rose about
one-fourth eclipsed. We looked at the Sun on a surface of water and saw
it distinctly. At the end when we found no part of the Sun was any
longer eclipsed, and that its disc appeared in the water as a complete
circle, its altitude was 12° in the E., less the one-third of a division
of the instrument, which itself was divided to thirds of a degree. One
must therefore reduce the stated altitude by one-ninth of a degree,
leaving, therefore, the true altitude as 11° 53′ 20″.” The skill and
care shown in this record shows that the Arab who observed this eclipse
nearly a thousand years ago must have been a man of a different type
from an ordinary resident at Bagdad in the year 1899. No description is
given of the instrument used, but presumably it was some kind of a
quadrant. It does not appear why some of the observations were made at
Bagdad and some at Cairo. The Bagdad observations commence with an
eclipse of the Sun on November 30, 829, and end with an eclipse of the
Moon on November 5, 933. The Cairo observations begin with an eclipse of
the Sun on December 12, 977, and end with an eclipse of the Sun on
January 24, 1004. These statements apply to the 25 observations which
Newcomb considered were trustworthy enough to be employed in his
researches, but he rejected three as imperfect.
I have broken away from the strict thread of chronological sequence in
order to keep together the notes respecting Arabian observations of
eclipses. Let us now revert to the European eclipses.
Under the date of A.D. 733, the _Anglo-Saxon Chronicle_ tells us that,
“In this year Æthelbald captured Somerton; and the Sun was eclipsed, and
all the Sun’s disc was like a black shield; and Acca was driven from his
bishopric.” Johnston suggests that the reference is to an annular
eclipse which he finds occurred on August 14, at about 8¼ h. in the
morning. In Schnurrer’s _Chronik der Seuchen_ (pt. i., § 113, p. 164),
it is stated that, “One year after the Arabs had been driven back across
the Pyrenees after the battle of Tours, the Sun was so much darkened on
the 19th of August as to excite universal terror.” It may be that the
English eclipse is here referred to, and a date wrong by five days
assigned to it by Schnurrer. Humboldt (_Cosmos_, vol. iv. p. 384, Bohn’s
ed.) reports this eclipse in an enumeration he gives of instances of the
Sun having been darkened.
On May 5, A.D. 840, there happened an eclipse of the Sun which, amongst
other effects, is said to have so greatly frightened Louis Le Debonnaire
(Charlemagne’s son) that it contributed to his death. The Emperor was
taken ill at Worms, and having been removed to Ingelheim, an island in
the Rhine, near Mayence, died there on June 20. Hind[75] found that this
was a total eclipse, and that the northern limit of totality passed
about 100 miles south of Worms. The middle of the eclipse occurred at
1h. 15m. p.m. with the Sun at an altitude of 57°. The duration of the
eclipse was unusually long, namely about 5½ minutes. With the Sun so
high and the obscuration lasting so long, this eclipse must have been
an unusually imposing one, and well calculated to inspire special alarm.
On Oct. 29, 878, in the reign of King Alfred, there was a total eclipse
visible at London. The mention of it in the _Anglo-Saxon Chronicle_ is
as follows:—“The Sun was eclipsed at 1 hour of the day.” No month is
given, and the year is said to have been 879, which is undoubtedly
wrong. Hind found that the central line of the eclipse passed about 20
miles N. of London, and that the totality lasted 1m. 51s. Tycho Brahe in
his _Historia Cœlestis_ quotes from the _Annales Fuldenses_ a statement
that the Sun was so much darkened after the 9th hour that the stars
appeared in the heavens.
Thorpe in his edition of the _Anglo-Saxon Chronicle_ quotes from Mr.
Richard Price a note which assigns the date of March 14, 880, to this
eclipse, and cites in confirmation a passage from the _Chronicle of
Florence of Worcester_, anno 879. The 880 eclipse is mentioned by Asser
in his _De Vitâ et Rebus gestis Alfredi_ in the words following:—“In the
same year [879] an eclipse of the Sun took place between three o’clock
and the evening, but nearer three o’clock.” The confusion of dates is
remarkable.
In the _Chronicon Scotorum_, under the date of 885, we find:—“An eclipse
of the Sun; and stars were seen in the heavens.” The reference appears
to be to the total eclipse of June 16, A.D. 885. The totality lasted
more than four minutes, and as the stars are said to have been visible
in the North of Ireland, doubtless that part of Ireland came within the
eclipse limits.
On Dec. 22, 968, there was an eclipse of the Sun, which was almost total
at London at about 8h. 33m. a.m., or soon after sunrise. The central
line passed across the S.-W. of England, and thence through France to
the Mediterranean. One Leon, a deacon at Corfu, observed this eclipse,
and has left behind what probably is the first perfectly explicit
mention of the Corona.[76]
On Aug. 30, 1030, there happened an eclipse visible in Norway, which has
already been alluded to on a previous page under the name of the
“eclipse of Stiklastad.” This was one of those eclipses, the
circumstances of which were examined many years ago in detail by Sir
G. B. Airy,[77] because he thought that information of value might be
obtained therefrom with respect to the motions of the Moon. Its
availability for that purpose has, however, been seriously questioned by
Professor Newcomb. Stiklastad is a place where a battle was fought, at
which Olav, King of Norway, is said to have been killed. While the
battle was in progress the Sun was totally eclipsed, and a red light
appeared around it. This is regarded as an early record of the Corona,
though not the first.[78] Johnston found that the eclipse was nearly
total at about 2h. 21m. p.m.
In 1033 there happened on June 29 an eclipse of the Sun, which
evidently had many observers, because it is mentioned by many
contemporary writers. For instance, the French historian, Glaber,[79]
says that “on the 3rd of the Calends of July there was an eclipse from
the sixth to the eighth hour of the day exceedingly terrible. For the
Sun became of a sapphire colour; in its upper part having the likeness
of a fourth part of the Moon.” This sufficiently harmonises with
Johnston’s calculations that about four-fifths of the Sun on the lower
side was covered at 10h. 50m. in the morning.
FOOTNOTES:
[Footnote 61: _Hist. Rome_, Book lv., chap. 22.]
[Footnote 62: Letter in the _Times_, July 19, 1872.]
[Footnote 63: _Hist. Rome_, Book lx., chap. 26.]
[Footnote 64: _Life of Apollonius of Tyana_, Book viii., c. 23.]
[Footnote 65: Plut. _Opera Mor. et Phil._, vol. xix. p. 682 Ed.
Lipsiæ, 1778.]
[Footnote 66: _Ast. Nach_, No. 1838, vol. lxxvii. p. 223: March 31,
1871.]
[Footnote 67: _Matheseos_, Lib. i., cap. 2, p. 5, Basileæ. 1533.]
[Footnote 68: _Historiæ_, Lib. xx., cap. 3, sec. 1.]
[Footnote 69: _Epitome Historiæ Ecclesiasticæ_, Lib. xii., cap. 8.]
[Footnote 70: _Historia Francorum_, Lib. ii., cap. 3 (_ad fin._).]
[Footnote 71: Mrs. D. P. Todd, _Total Eclipses of the Sun_, p. 101.]
[Footnote 72: _The Anglo-Saxon Chronicle_, vol. ii. p. 14. Ed. B.
Thorpe, 1861.]
[Footnote 73: Prof. S. Ockley, _History of the Saracens_, vol ii. p.
110. Camb. 1757.]
[Footnote 74: It should be stated that prior to the publication of
the work in a book form the greater part of the eclipse observations
had been published in the _Mémoires de l’Institut National des
Sciences et Arts: Sciences Mathématiques et Physiques_, tome ii.]
[Footnote 75: Letter in the _Times_, July 19, 1872.]
[Footnote 76: J. F. J. Schmidt, _Ast. Nach._, vol. lxxvii. p. 127,
Feb. 1, 1871.]
[Footnote 77: _Memoirs_, R.A.S., vol. xxvi. p. 131, 1858.]
[Footnote 78: J. L. E. Dreyer, _Nature_, vol. xvi. p. 549, Oct. 25,
1877.]
CHAPTER XII.
ECLIPSES OF THE SUN MENTIONED IN HISTORY.—
MEDIÆVAL AND MODERN.
One of the most celebrated eclipses of mediæval times was that of August
2, 1133, visible as a total eclipse in Scotland. It was considered a
presage of misfortune to Henry I. and was thus referred to by William of
Malmesbury[80]:—
“The elements manifested their sorrow at this great man’s last departure
from England. For the Sun on that day at the 6th hour shrouded his
glorious face, as the poets say, in hideous darkness agitating the
hearts of men by an eclipse; and on the 6th day of the week early in the
morning there was so great an earthquake that the ground appeared
absolutely to sink down; an horrid noise being first heard beneath the
surface.”
This eclipse is also alluded to in the _Anglo-Saxon Chronicle_ though
the year is wrongly given as 1135 instead of 1133 as it certainly was.
The _Chronicle_ says:—“In this year King Henry went over sea at Lammas,
and the second day as he lay and slept on the ship the day darkened over
all lands; and the Sun became as it were a three-night-old Moon, and the
stars about it at mid-day. Men were greatly wonder-stricken and
affrighted, and said that a great thing should come hereafter. So it
did, for the same year the king died on the following day after St.
Andrew’s Mass day, Dec. 2, in Normandy.” The king did die in 1135, but
there was no eclipse of the August new Moon, and without doubt the
writer has muddled up the year of the eclipse and of the king’s
departure from England (to which he never returned) and the year of his
death. Calvisius states that this eclipse was observed in Flanders and
that the stars appeared.
Respecting the above-mentioned discrepancy Mrs. Todd aptly remarks:—“So
Henry must have died in 1133, which he _did not_; or else there must
have been an eclipse in 1135, which there _was not_. But this is not the
only labyrinth into which chronology and old eclipses, imagination, and
computation, lead the unwary searcher.” Professor Freeman’s explanation
fairly clears up the difficulty:—“The fact that he never came back to
England, together with the circumstances of his voyage, seems to have
made a deep impression on men’s minds. In popular belief the signs and
wonders which marked his last voyage were transferred to the Lammas-tide
before his death two years later.”[81] The central line of this eclipse
traversed Scotland from Ross to Forfar and the eclipse was of course
large in every part of the country. The totality lasted 4m. 20s. in
Forfarshire.
Hind has furnished some further information respecting this eclipse. It
appears that during the existence of the Kingdom of Jerusalem created by
the Crusaders an eclipse occurred which would appear to have been total
at Jerusalem or in its immediate neighbourhood. No date is given and a
date can only be guessed, and Hind guessed that the eclipse of 1133 was
the one referred to. He found that after leaving Scotland and crossing
Europe the central line of the 1133 eclipse entered Palestine near Jaffa
and passed over Jerusalem where the Sun was hidden for 4¼ minutes at
about 3h. p.m. From Nablous on the N. to Ascalon on the S. the country
was in darkness for nearly the same period of time. The alternative
eclipses to this one would be those of Sept. 4, 1187, magnitude at
Jerusalem 9/10ths of the Sun’s diameter; or June 23, 1191, magnitude at
the same place about 7/10ths; but these do not seem to harmonise so well
with the accounts handed down to us as does the eclipse of 1133.
In 1140, on March 20, there happened a total eclipse of the Sun visible
in England which is thus referred to by William of Malmesbury[82]:—
“During this year, in Lent, on the 13th of the Calends of April, at the
9th hour of the 4th day of the week, there was an eclipse, throughout
England, as I have heard. With us, indeed, and with all our neighbours,
the obscuration of the Sun also was so remarkable, that persons sitting
at table, as it then happened almost everywhere, for it was Lent, at
first feared that Chaos was come again: afterwards, learning the cause,
they went out and beheld the stars around the Sun. It was thought and
said by many, not untruly, that the King [Stephen] would not continue a
year in the government.”
The same eclipse is also thus mentioned in the _Anglo-Saxon
Chronicle_:—“Afterwards in Lent the Sun and the day darkened about the
noontide of the day, when men were eating, and they lighted candles to
eat by; and that was the 13th of the Calends of April, March 20. Men
were greatly wonder-stricken.” The greatest obscuration at London took
place at 2h. 36m. p.m., but it is not quite clear whether the line of
totality did actually pass over London.
It was long supposed that this eclipse was total at London, an idea
which seems to have arisen from Halley having told the Royal Society
anent the total eclipse of May 3, 1715, that he could not find that any
total eclipse had been visible at London since March 20, 1140. In
consequence of this statement of Halley’s, Hind carefully investigated
the circumstances of this eclipse, and found that it had _not_ been
total at London. The central line entered our island at Aberystwith, and
passing near Shrewsbury, Stafford, Derby, Nottingham, and Lincoln,
reached the German Ocean, 10 miles S. of Saltfleet. The southern limit
of the zone of totality passed through the South Midland counties, and
the nearest point of approach to London was a point on the borders of
Northamptonshire and Bedfordshire. For a position on the central line
near Stafford, Hind found that the totality began at 2h. 36m. p.m. local
mean time, the duration being 3m. 26s., and the Sun’s altitude being
more than 30°. The stars seen were probably the planets Mercury and
Venus, then within a degree of each other, and 10° W. of the Sun, and
perhaps the stars forming the well-known “Square of Pegasus.” Mars and
Saturn were also, at that time, within a degree of each other, but very
near the western horizon. It is therefore necessary to look further back
than 1140 to find a total solar eclipse visible in London.[83]
A solar eclipse seems to have been alluded to by certain historians as
having happened in A.D. 1153. We have the obscure statement that
“something singular happened to the Sun the day after the Conversion of
St. Paul.” A somewhat large eclipse having been visible at Augsburg in
Germany, on January 26, this may have been the “something” referred to.
It would seem that about 11/12ths of the Sun’s diameter was covered.
On May 14, A.D. 1230, there happened a great eclipse of the Sun, thus
described by Roger of Wendover[84]:—“On the 14th of May, which was the
Tuesday in Rogation Week, an unusual eclipse of the Sun took place very
early in the morning, immediately after sunrise; and it became so dark
that the labourers, who had commenced their morning’s work, were obliged
to leave it, and returned again to their beds to sleep; but in about an
hour’s time, to the astonishment of many, the Sun regained its usual
brightness.” This eclipse, as regards its total phase, is said by
Johnston to have begun in the horizon, a little to the N. of London, in
the early morning.
On June 3, A.D. 1239, and October 6, 1241, there occurred total eclipses
of the Sun, which have been very carefully discussed by Professor
Celoria of Milan, with the view of using them in investigations into the
Moon’s mean motion.[85] The second of these eclipses is mentioned by
Tycho Brahe.[86] He states that “a few stars appeared about noonday, and
the Sun was hidden from sight in a clear sky.” The eclipse was total in
Eastern Europe.
Dr. Lingard,[87] the well-known Roman Catholic historian, speaking of
the battle of Cressy, which was fought on August 26, 1346, says:—“Never,
perhaps, were preparations for battle made under circumstances so truly
awful. On that very day the Sun suffered a partial eclipse: birds in
clouds, precursors of a storm, flew screaming over the two armies; and
the rain fell in torrents, accompanied with incessant thunder and
lightning. About 5 in the afternoon, the weather cleared up, the Sun in
full splendour darted his rays in the eyes of the enemy; and the
Genoese, setting up their shouts, discharged their quarrels.” This was
not an eclipse, for none was due to take place; and the phenomenon could
only have been meteorological—dense clouds or something of that sort in
the sky.
On June 16, 1406, there was a large eclipse of the Sun, 9/10ths of its
diameter being covered at London; but on the Continent it seems to have
been total. It is stated that the darkness was such that people could
hardly recognise one another.
One of the most celebrated eclipses during the Middle Ages was
undoubtedly that of June 17, 1433. This was long remembered in Scotland
as the “Black Hour,” and its circumstances were fully investigated some
years ago by Hind. It was a remarkable eclipse in that the Moon was
within 13° of perigee and the Sun only 2° from apogee. The central line
traversed Scotland in a south-easterly direction from Ross to Forfar,
passing near Inverness and Dundee. Maclaurin[88] who lived in the early
part of the last century mentions that in his time a manuscript account
of this eclipse was preserved in the library of the University of
Edinburgh wherein the darkness is said to have come on at about 3 p.m.,
and to have been very profound. The duration of the totality at
Inverness was 4m. 32s.; at Edinburgh 3m. 41s. The central line passed
from Britain to the N. of Frankfort-on-the-Maine, through Bavaria, to
the Dardanelles, to the S. of Aleppo and thence nearly parallel to the
river Euphrates to the N.-E. border of Arabia. In Turkey, according to
Calvisius, “near evening the light of the Sun was so overpowered that
darkness covered the land.”
In 1544, on Jan. 24, there occurred an eclipse of the Sun which was
nearly but not quite total. The chief interest arises from the fact that
it was one of the first observed by professed astronomers: Gemma Frisius
saw it at Louvain.
Kepler says[89] that the day became dark like the twilight of evening
and that the birds which from the break of day had been singing became
mute. The middle of the eclipse was at about 9 a.m.
In 1560 an eclipse of the Sun took place which was total in Spain and
Portugal. Clavius who observed it at Coimbra says[90] that “the Sun
remained obscured for no little time: there was darkness greater than
that of night, no one could see where he trod and the stars shone very
brightly in the sky: the birds moreover, wonderful to say, fell down to
the ground in fright at such startling darkness.” Kepler is responsible
for the statement that Tycho Brahe did not believe this, and wrote to
Clavius to that effect 40 years afterwards.
In 1567 there was an annular eclipse visible at Rome on April 9. Clavius
says[91] that “the whole Sun was not eclipsed but that there was left a
bright circle all round.” This in set terms is a description of an
annular eclipse, but Johnston who calculated that at Rome the greatest
obscuration took place at 20m. past noon points out that the
augmentation of the Moon’s semi-diameter would almost have produced
totality. Tycho tells us that he saw this eclipse on the shores of the
Baltic when a young man about 20 years of age.
The total eclipse of February 25, 1598, long left a special mark on the
memories of the people of Scotland. The day was spoken of as “Black
Saturday.” Maclaurin states[92]:—“There is a tradition that some persons
in the North lost their way in the time of this eclipse, and perished in
the snow”—a statement which Hind discredits. The central line passed
from near Stranraer, over Dalkeith, and therefore Edinburgh was within
the zone of totality. Totality came on at Edinburgh at 10h. 15m. and
lasted 1m. 30s. From the rapid motion of the Moon in declination, the
course of the central line was a quickly ascending one in latitude on
the Earth’s surface, the totality passing off within the Arctic circle.
Kepler in his account of the new star in the constellation Ophiuchus[93]
refers to the total eclipse of the Sun of October 12, 1605, as having
been observed at Naples, and that the “Red Flames” were visible as a rim
of red light round the Sun’s disc: at least this seems to be the
construction which may fairly be put upon the Latin of the original
description.
The partial eclipse of the Sun of May 30, 1612, is recorded to have been
seen “through a tube.” No doubt this is an allusion to the
newly-invented instrument which we now call the telescope. Seemingly
this is the first eclipse of the Sun so observed, but it is on record
that an eclipse of the Moon had been previously observed through a
telescope. This was the lunar eclipse of July 6, 1610, though the
observer’s name has not been handed down to us.
The eclipse of April 8, 1652, is another of those Scotch eclipses, as we
may call them, which left their mark on the people of that country.
Maclaurin[94] speaks of it in his time (he died in 1746) as one of the
two central eclipses which are “still famous among the populace in this
country” [Scotland], and “known amongst them by the appellation of Mirk
Monday.” The central line passed over the S.E. of Ireland, near Wexford
and Wicklow, and reaching Scotland near Burrow Head in Wigtownshire, and
passing not far from Edinburgh, Montrose and Aberdeen, quitted Scotland
at Peterhead. Greenock and Elgin were near the northern limit of the
zone of totality, and the Cheviots and Berwick upon the southern limit.
The eclipse was observed at Carrickfergus by Dr. Wyberd.[95] Hind found
that its duration there was but 44s. This short duration, he suggested,
may partly explain the curious remark of Dr. Wyberd that when the Sun
was reduced to “a very slender crescent of light, the Moon all at once
threw herself within the margin of the solar disc with such agility that
she seemed to revolve like an upper millstone, affording a pleasant
spectacle of rotatory motion.” Wyberd’s further description clearly
applies to the Corona. A Scotch account says that “the country people
tilling, loosed their ploughs. The birds dropped to the ground.”
The eclipse of November 4, 1668, visible as a partial one in England,
was of no particular interest in itself but deserves notice as having
been observed by Flamsteed,[96] who gives a few diagrams of his
observations at Derby. He states that the eclipse came on much earlier
than had been predicted. It was well known at this time that the tables
of the Sun and Moon then in use were very defective, and it was a
recognition of this fact which eventually led to the foundation of the
Greenwich Observatory in 1675.
On September 23, 1699, an eclipse of the Sun occurred which was total to
the N. of Caithness for the very brief space of 10-15 secs. At
Edinburgh, about 11/12ths of the Sun’s diameter was obscured. In the
Appendix to Pepys’s _Diary_[97] there is a letter from Dr. Wallis
mentioning that his daughter’s attention was called to it by noticing
“the light of the Sun look somewhat dim” at about 9 a.m., whilst she
was writing a letter, she knowing nothing of the eclipse.
An eclipse of the Sun occurred on May 12, 1706, which was visible as a
partial eclipse in England and was total on the Continent, especially in
Switzerland. A certain Captain Stannyan who made observations at Berne,
writes thus to Flamsteed[98]:—“That the Sun was totally darkened there
for four and a half minutes of time; that a fixed star and a planet
appeared very bright; _and that his getting out of his eclipse was
preceded by a blood-red streak of light from its left limb, which
continued not longer than six or seven seconds of time_; then part of
the Sun’s disc appeared all of a sudden as bright as Venus was ever seen
in the night; nay, brighter; and in that very instant gave a light and
shadow to things as strong as the Moon uses to do.”
On this communication Flamsteed remarks:—“The Captain is the first man I
ever heard of that took notice of a red streak preceding the emersion of
the Sun’s body from a total eclipse, and I take notice of it to you [the
Royal Society], because it infers that the Moon has an atmosphere; and
its short continuance, if only six or seven seconds’ time, tells us that
its height was not more than five or six hundredths part of her
diameter.”
On the whole, perhaps, the most celebrated eclipse of the Sun ever
recorded in England was that of May 3, 1715. The line of totality passed
right across England from Cornwall to Norfolk, and the phenomenon was
carefully observed and described by the most experienced astronomer of
the time, Dr. Edmund Halley. The line of totality passed over London
amongst other places, and as the maximum phase took place soon after 9
a.m. on a fine spring morning, the inhabitants of the Metropolis saw a
sight which their successors will not see again till many generations
have come and gone. Halley has left behind him an exceedingly
interesting account of this event, some allusions to which have already
been made.
He seems to have seen what we call the Corona, described by him however
as a “luminous ring,” “of a pale whiteness, or rather pearl colour, a
little tinged with the colours of the Iris, and concentric with the
Moon.” He speaks also of a dusky but strong red light which seemed to
colour the dark edge of the Moon just before the Sun emerged from
totality. Jupiter, Mercury, Venus, and the stars Capella and Aldebaran
were seen in London, whilst N. of London, more directly under the
central line, as many as twenty stars were seen.
The inhabitants of England who lived in the reign of George I. were
singularly fortunate in their chances of seeing total eclipses of the
Sun, for only nine years after[99] the one just described, namely, on
May 22, 1724, another total eclipse occurred. The central line crossed
some of the southern countries, and the phenomenon was well seen and
reported on by Dr. Stukeley,[100] who stationed himself on Haraden Hill,
near Salisbury. The Doctor says of the darkness that he seemed to “feel
it, as it were, drop upon us ... like a great dark mantle,” and that
during the totality the spectacle presented to his view “was beyond all
that he had ever seen or could picture to his imagination the most
solemn.” He could with difficulty discern the faces of his companions
which had a ghastly startling appearance. When the totality was ending
there appeared a small lucid spot, and from it ran a rim of faint
brightness. In about 3½ minutes from this appearance the hill-tops
changed from black to blue, the horizon gave out the grey streaks
previous to morning dawn, and the birds sprang joyously into the air.
This eclipse seems to have had royal observers. It was watched at
Kensington apparently by the King or some of the royal family of
England, and at Trianon (Paris) by the King of France,[101] under the
competent guidance of Maraldi, Cassini and De Louville. It was the last
which was visible as a total one in any part of England.
On May 2, 1733, there was an eclipse of the Sun, which was total in
Sweden and partial in England. In Sweden the total obscuration lasted
more than 3 minutes. Jupiter, the stars in Ursa Major, Capella, and
several other stars were visible to the naked eye, as also was a
luminous ring round the Sun. Three or four spots of reddish colour were
also perceived near the limb of the Moon, but not in immediate contact
with it. These so-called red “spots” were doubtless the Red Flames of
the present century, and the luminous ring the Corona.
On March 1, 1737, a good annular eclipse was observed at Edinburgh by
Maclaurin.[102] In his account he says:—“A little before the annulus was
complete a remarkable point or speck of pale light appeared near the
middle of the part of the Moon’s circumference that was not yet come
upon the disc of the Sun.... During the appearance of the annulus the
direct light of the Sun was still very considerable, but the places that
were shaded from his light appeared gloomy. There was a dusk in the
atmosphere, especially towards the N. and E. In those chambers which had
not their lights westwards the obscurity was considerable. Venus
appeared plainly, and continued visible long after the annulus was
dissolved, and I am told that other stars were seen by some.” Lord
Aberdour mentions a narrow streak of dusky red light on the dark edge of
the Moon immediately before the ring was completed, and after it was
dissolved. No doubt this is a record of the “Red Flames.”
In 1748 Scotland was again favoured with a central eclipse, but it was
only annular. The Earl of Morton[103] and James Short, the optician, who
observed the phenomenon at Aberdour Castle, 10 miles N.-W. of Edinburgh,
just outside the line of annularity, saw a brown coloured light
stretching along the circumference of the Moon from each of the cusps.
A “star” (probably the planet Venus) was seen to the E. of the Sun.
The annular eclipse of April 1, 1764, visible as such in North Kent, was
the subject of the following quaint letter by the Rev. Dr. Stukeley:—
“To the Printer of _Whitehall Evening Post_,—
“In regard to the approaching solar eclipse of Sunday, April 1, I
think it advisable to remark that, it happening in the time of
divine service, it is desired you would insert this caution in your
public paper. The eclipse begins soon after 9, the middle a little
before 11, the end a little after 12. There will be no total
darkness in the very middle, observable in this metropolis, but as
people’s curiositys will not be over with the middle of the
eclipse, if the church service be ordered to begin a little before
12, it will properly be morning prayer, and an uniformity preserved
in our duty to the Supreme Being, the author of these amazing
celestial movements,—
Yours,
RECTOR OF ST. GEO., Q.S.”[104]
The year 1766 furnishes the somewhat rare case of a total eclipse of the
Sun observed on board ship on the high seas. The observers were officers
of the French man-of-war the _Comte d’Artois_. Though the total
obscuration lasted only 53 secs., there was seen a luminous ring about
the Moon which had four remarkable expansions, situate at a distance of
90° from each other.[105] These expansions are doubtless those rays
which we now speak of as “streamers” from the Corona.
Curiously enough the next important total eclipse deserving of notice
was also observed at sea. This was the eclipse of June 24, 1778. The
observer was the Spanish Admiral, Don Antonio Ulloa, who was passing
from the Azores to Cape St. Vincent. The total obscuration lasted 4
minutes. The luminous ring presented a very beautiful appearance: out of
it there issued forth rays of light which reached to the distance of a
diameter of the Moon. Before it became very conspicuous stars of the 1st
and 2nd magnitudes were distinctly visible, but when it attained its
greatest brilliancy, only stars of the 1st magnitude could be perceived.
“The darkness was such that persons who were asleep and happened to
wake, thought that they had slept the whole evening and only waked when
the night was pretty far advanced. The fowls, birds, and other animals
on board took their usual position for sleeping, as if it had been
night.”[106]
On Sept. 5, 1793, there happened an eclipse which, annular to the N. of
Scotland, was seen and observed in England by Sir W. Herschel[107] as a
partial eclipse. He made some important observations on the Moon on this
occasion measuring the height of several of the lunar mountains.
Considerations respecting the shape of one of the Moon’s horns led him
to form an opinion adverse to the idea that there the Moon had an
atmosphere.
FOOTNOTES:
[Footnote 79: _Historiarum Sui Temporis_, Lib. iv., cap. 9.]
[Footnote 80: _Historia Novella_, Lib. i., sec. 8.]
[Footnote 81: _Norman Conquest_, vol. v. p. 239.]
[Footnote 82: _Historia Novella_, Lib. ii., sec. 35.]
[Footnote 83: Letter in the _Times_, July 28, 1871.]
[Footnote 84: Rogerus de Wendover, _Flores Historiarum_, vol. ii. p.
535, Bohn’s ed.]
[Footnote 85: _Sugli Eclissi Solari Totali del 3 Giugno 1239, e del
6 Ottobre 1241_ in the _Memorie del R. Istituto Lombardo di Scienze
e Littere_, vol. xiii. p. 275.]
[Footnote 86: _Historia Cœlestis_, vol. i. p. 38.]
[Footnote 87: _Hist. Engl._, vol. iii. chap. xviii. p. 50, 4to. ed.]
[Footnote 88: _Phil. Trans._, vol. xl. p. 194, 1737.]
[Footnote 89: _Astronomiæ Pars Optica_, c. viii. sec. 3; _Opera
Omnia_, vol. ii. p. 315. Ed. Frisch, 1859.]
[Footnote 90: Quoted by Kepler, as above, at p. 315.]
[Footnote 91: _Commentarius in Sacroboscum_, cap. iv.; quoted in
Kepler’s _Astronomiæ Pars Optica_, c. viii. sec. 3; _Opera Omnia_,
vol ii. p. 316. Ed. Frisch, 1859.]
[Footnote 92: _Phil. Trans._, vol. xl. p. 193; 1737.]
[Footnote 93: _De Stellâ Novâ in Pede Serpentarii_, p. 115; Pragæ,
1606.]
[Footnote 94: _Phil. Trans._, vol. xl. p. 193; 1737.]
[Footnote 95: V. Wing, _Astronomia Britannica_, p. 355.]
[Footnote 96: _Historia Cœlestis_, vol. i. pp. 7 and 21.]
[Footnote 97: _Diary of Samuel Pepys_, vol. vi. p. 208; Ed. M.
Bright, 1879.]
[Footnote 98: _Phil. Trans._, vol. xxv. p. 2240; 1706.]
[Footnote 99: Being half a _Saros_ period (see p. 20, _ante_).]
[Footnote 100: _Itinerarium Curiosum_, 2nd ed., vol. i. p. 180.]
[Footnote 101: _Mem. de Mathématique et de Physique de l’Acad. des
Sciences_, 1724, p. 259.]
[Footnote 102: _Phil. Trans._, vol. xl. pp. 181, 184. 1737.]
[Footnote 103: _Phil. Trans._, vol. xlv. p. 586. 1750. This is the
man who under the designation of “Lord Aberdour” observed the
eclipse of 1737 (_ante_).]
[Footnote 104: Rev. W. Stukeley, Rector of St. George’s, Queen’s
Square, London, _Diary_, vol. xx. p. 44, ed. “Surtees Soc.,” vol.
lxxvi. p. 384.]
[Footnote 105: Le Gentil, _Voyage dans les Mers de l’Inde_, vol. ii.
p. 16. Paris, 1769.]
[Footnote 106: _Phil. Trans._, vol. lxix. p. 105. 1779.]
[Footnote 107: _Phil. Trans._, vol. lxxxiv. p. 39. 1794.]
CHAPTER XIII.
ECLIPSES OF THE SUN DURING THE NINETEENTH CENTURY.
Observations of total solar eclipses during the 19th century have been,
for the most part, carried on under circumstances so essentially
different from everything that has gone before, that not only does a new
chapter seem desirable but also new form of treatment. Up to the
beginning of the 18th century the observations (even the best of them)
may be said to have been made and recorded with but few exceptions by
unskilled observers with no clear ideas as to what they should look for
and what they might expect to see. Things improved a little during the
18th century and the observations by Halley, Maclaurin, Bradley, Don
Antonio Ulloa, Sir W. Herschel, and others in particular rose to a much
higher standard than any which had preceded them. However, it has only
been during the 19th century, and especially during the latter half of
it, that total eclipses of the Sun have been observed under
circumstances calculated to extract from them large and solid extensions
of scientific knowledge. Inasmuch as it has been deemed convenient to
sort out and classify our knowledge under particular heads in previous
chapters, I shall in this chapter speak only of the leading facts of
each eclipse in such an outline form as will avoid as far as possible
unnecessary repetition.
In 1806 a total eclipse of the Sun occurred, visible in N. America.
Observations made in the United States have been handed down to us. Don
Joachin Ferrer, a Spanish astronomer, observed the eclipse at Kinderhook
in the State of New York. The totality lasted more than 4½ m.—a somewhat
unusual length of time. One or two planets and a few 1st magnitude stars
were seen. During the totality there was a slight fall of dew.
On Nov. 19, 1816, there occurred the first total eclipse of the Sun in
the 19th century, the central line of which passed over Europe. There is
only one known observation of the total phase, and this was by Hagen at
Culm in Bohemia, but he appears to have seen only the beginning of the
totality and not the whole of it.
A partial eclipse of the Sun visible as such in England but which was
annular in the Shetland Isles took place on Sept. 7, 1820. The only
reason why this is worth mention is for its political associations. The
trial of Queen Caroline was going on in the House of Lords, and the
House suspended its sitting for a short time for the sake of the
eclipse.
On May 15, 1836, there occurred an annular eclipse of the Sun, which
though it was nowhere total, may be looked upon as the first of the
modern eclipses the observations of which have taken such a great
development during recent years. The annularity of this eclipse was
observed in the N. of England and in the S. of Scotland; and it was at
Jedburgh in Roxburghshire that Mr. Francis Baily[108] observed that
feature of eclipses of the Sun now universally known as “Baily’s Beads.”
Some indications of the Red Flames were also obtained at places where
the eclipse was annular.
Probably it was the recognition of Baily’s Beads as a regular
concomitant of eclipses of the Sun, which helped to pave the way for the
extensive preparations made in France, Italy, Austria, and Russia for
observing the total eclipse of July 8, 1842. Many of the most eminent
astronomers of Europe repaired to different stations on the central line
in order to see the phenomenon. Amongst these may be named Arago, Valz,
Airy, Carlini, Santini, and O. Struve. The eclipse was witnessed under
favourable circumstances at all the various stations on the central line
across Europe, from Perpignan in France in the West to Lipesk in Russia
in the East.
Arago wrote[109] such an exceedingly graphic account of this eclipse
from what may be termed the standpoint of the general public, that I
will quote it at some length, because, with an alteration of date, it
might be re-written and applied to every total eclipse visible in much
populated tracts of country.
“At Perpignan persons who were seriously unwell alone remained within
doors. As soon as day began to break the population covered the terraces
and battlements of the town, as well as all the little eminences in the
neighbourhood, in hopes of obtaining a view of the Sun as he ascended
above the horizon. At the citadel we had under our eyes, besides
numerous groups of citizens established on the slopes, a body of
soldiers about to be reviewed.
“The hour of the commencement of the eclipse drew nigh. More than twenty
thousand persons, with smoked glasses in their hands, were examining the
radiant globe projected upon an azure sky. Although armed with our
powerful telescopes, we had hardly begun to discern the small notch on
the western limb of the Sun, when an immense exclamation, formed by the
blending together of twenty thousand different voices, announced to us
that we had anticipated by only a few seconds the observation made with
the unaided eye by twenty thousand astronomers equipped for the
occasion, whose first essay this was. A lively curiosity, a spirit of
emulation, the desire of not being outdone, had the privilege of giving
to the natural vision an unusual power of penetration. During the
interval that elapsed between this moment and the almost total
disappearance of the Sun we remarked nothing worthy of relation in the
countenances of so many spectators. But when the Sun, reduced to a very
narrow filament, began to throw upon the horizon only a very feeble
light, a sort of uneasiness seized upon all; every person felt a desire
to communicate his impressions to those around him. Hence arose a deep
murmur, resembling that sent forth by the distant ocean after a tempest.
The hum of voices increased in intensity as the solar crescent grew more
slender; at length the crescent disappeared, darkness suddenly succeeded
light, and an absolute silence marked this phase of the eclipse with as
great precision as did the pendulum of our astronomical clock. The
phenomenon in its magnificence had triumphed over the petulance of
youth, over the levity which certain persons assume as a sign of
superiority, over the noisy indifference of which soldiers usually make
profession. A profound stillness also reigned in the air; the birds had
ceased to sing. After an interval of solemn expectation, which lasted
about two minutes, transports of joy, shouts of enthusiastic applause,
saluted with the same accord, the same spontaneous feeling, the first
reappearance of the rays of the Sun. To a condition of melancholy
produced by sentiments of an indefinable nature there succeeded a lively
and intelligible feeling of satisfaction which no one sought to escape
from or moderate the impulses of. To the majority of the public the
phenomenon had arrived at its term. The other phases of the eclipse had
few attentive spectators beyond the persons devoted especially to
astronomical pursuits.”
The total eclipse of July 28, 1851, may be said to have been the first
which was the subject of an “Eclipse Expedition,” a phrase which of late
years has become exceedingly familiar. The total phase was visible in
Norway and Sweden, and great numbers of astronomers from all parts of
Europe flocked to those countries. Amongst those who went from England
were Sir G. B. Airy, the Astronomer Royal (then Mr. Airy), Mr. J. R.
Hind and Mr. Lassell. The Red Flames were very much in evidence, and the
fact that they belonged to the Sun and not to the Moon was clearly
established. Hind mentions that “the aspect of Nature during the total
eclipse was grand beyond description.” This feature is dwelt upon with
more than usual emphasis in many of the published accounts. I have never
seen it suggested that the mountainous character of the country may have
had something to do with it, but that idea would seem not improbable.
In the year 1858, two central eclipses of the Sun occurred, both
presenting some features of interest. That of March 15 was annular, the
central line passing across England from Lyme Regis in Dorsetshire to
the Wash, traversing portions of Somersetshire, Wiltshire, Berkshire,
Oxfordshire, Northamptonshire, Lincolnshire, and Norfolk. The weather
generally was unfavourable and the annular phase was only observed at a
few places, but important meteorological observations were made and
yielded results, as regards the diminution of temperature, which were
very definite. All over the country rooks and pigeons were seen
returning home during the greatest obscuration; starlings in many places
took flight; at Oxford a thrush commenced its evening song; at Ventnor a
fish in an aquarium, ordinarily visible in the evening only, was in full
activity about the time of greatest gloom; and generally, it was noted
that the birds stopped singing and flew low from bush to bush. The
darkness, though nowhere intense, was everywhere very appreciable and
decided. The second central eclipse of 1858 took place on September 7
and was observed in Peru by Lieutenant Gilliss of the U.S. Navy. The
totality only lasted one minute, and the general features of a total
eclipse do not appear to have been very conspicuously visible. Gilliss
remarks[110]:—“Two citizens of Olmos stood within a few feet of me,
watching in silence, and with anxious countenances, the rapid and
fearful decrease of light. They were wholly ignorant that any sudden
effect would follow the total obscuration of the Sun. At that instant
one exclaimed in terror “_La Gloria_,” and both, I believe, fell to
their knees, filled with awe. They appreciated the resemblance of the
Corona to the halos with which the old masters have encircled their
ideals of the heads of our Saviour and the Madonna, and devoutly
regarded this as a manifestation of the Divine Presence.”
The year 1860 saw the departure from England of the first great Ship
Expedition to see an eclipse. One was due to happen on July 18, and a
large party went out from England to Spain in H.M.S. _Himalaya_. Mr. De
La Rue took a very well-equipped photographic detachment, and his
photographs were eminently successful. This eclipse settled for ever the
doubt as to whether the Red Flames belonged to the Sun or the Moon, and
in favour of the former view.
The years 1868, 1869, and 1870 were each marked by total eclipses,
which were observed to a greater or less extent. In the first-named year
the eclipse occurred on August 18, the central line passing across
India. The weather was not everywhere favourable, but several
expeditions were dispatched to the East Indies. The spectroscope was
largely brought into play with the immediate result of showing that the
Corona was to be deemed a sort of atmosphere of the Sun, not
self-luminous, but shining by reflected light. The eclipse of 1869 was
observed by several well-equipped parties in the United States, and a
very complete series of excellent photographs was obtained.
To view the eclipse of December 22, 1870, several expeditions were
dispatched, the central line passing over some very accessible places in
Spain, Sicily, and North Africa. The English observers went chiefly in
H.M.S. _Urgent_, though some of them travelled overland to Sicily. The
expenses, both of the sea and land parties, were to a large extent
defrayed by Her Majesty’s Government. It deserves to be noted that so
great was the anxiety of the French astronomer Janssen to see this
eclipse, that he determined to try and escape in a balloon from Paris
(then besieged by the Germans) and succeeded, carrying his instruments
with him. The weather seriously interfered with the work of all the
observers who went out to see this eclipse, which was the more to be
regretted because the preparations had been on a very extensive and
costly scale. The chief result was that it was ascertained that the Red
Flames (hence forward generally called “Prominences”) are composed of
hydrogen gas in an incandescent state.
The year 1871 saw, on December 12, another Indian eclipse, noteworthy
for the numerous and excellent photographs which were obtained of the
Corona, of the rifts in it, and of the general details, which were well
recorded on the plates.
There was an eclipse visible in South Africa on April 16, 1874. Some
useful naked eye views were obtained and recorded, but as no
photographic work was done, this eclipse cannot be said to come into
line with those which preceded or followed it.
In the following year, that is to say on April 6, 1875, there was a
total eclipse of the Sun, visible in the far East, especially Siam; but
the distance from England, coupled with the very generally unfavourable
weather, prevented this from being anything more than a second-class
total eclipse, so to speak, although extensive preparations had been
made, and the sum of £1000 had been granted by the British Government
towards the expenses. A certain number of photographs were obtained, but
none of any very great value.
Perhaps of the next eclipse which we have to consider, it may be said
that the circumstances were more varied than those of any other during
the second half of the 19th century. The eclipse in question occurred on
July 29, 1878.
Several favourable circumstances concurred to make it a notable event.
In the first place, the central line passed entirely across the United
States; in other words, across a long stretch of inhabited and civilised
territory, accessible from both sides to a nation well provided with the
requisite scientific skill and material resources of every kind. But
there was another special and rare facility available: the central line
crossed the chain of the Rocky Mountains, an elevated locality, which an
American writer speaks of as overhung by “skies of such limpid
clearness, that on several evenings Jupiter’s satellites were seen with
the naked eye.” On the summit of a certain peak, known as Pike’s Peak, a
party of skilled observers, headed by Professor Langley, observed the
wonderful developments of the Corona, mentioned on a previous page. The
fact that such a display came under the eyes of man was no doubt mainly
due to the superbly clear atmosphere through which the observations were
made. That this is not a mere supposition may be inferred from the fact
that at the lower elevation of only 8000 feet, instead of 14,000 feet,
the Coronal streamers were seen by Professor Newcomb’s party, far less
extended than Langley saw them. Perhaps the best proof of the importance
of a diaphanous sky is to be found in the fact that on the summit of
Pike’s Peak, the Corona remained visible for fully 4 minutes after the
total phase had come to an end. A comparison of the descriptions shows
that even at the elevation of 10,200 ft. the observers placed there,
whilst they were better off than those at 8000 ft., assuredly did not
see so much or so well as those at 14,000 ft.
There occurred a total eclipse on July 11, 1880, visible in California,
but as the totality lasted only 32 secs. and the Sun’s elevation was
only 11°, not much was got out of this eclipse notwithstanding that it
was observed in a cloudless sky at a station 6000 ft. above the sea.
The eclipse of May 17, 1882, yielded several interesting and important
features although the totality was short—only about 1¼ minutes. Here
again favourable local circumstances helped astronomers in more ways
than one. It was in Egypt that the eclipse was visible, and Egypt is a
country which it is exceedingly easy for travellers to reach, and it is
also noted for its clear skies. These were doubtless two of the reasons
which combined to inspire the elaborate preparations which were made for
photographic and spectroscopic observations. The former resulted in a
very unprecedented success. One of Dr. Schuster’s photographs of the
totality showed not only the expected Corona, but an unexpected comet.
Though on more than one previous occasion in history the darkness which
is a special accompaniment of a total eclipse had caused a comet to be
seen, yet the 1882 eclipse was the first at which a comet had thrust
itself upon the notice of astronomers by means of a photographic plate.
It will be remembered that the political circumstances of Egypt in 1882
were of a somewhat strained character and probably this contributed to
the development of an unusual amount of astronomical competition in
connection with this eclipse. Not only did the Egyptian Government grant
special facilities, but strong parties went out representing England,
France, and Italy, although not perhaps in set terms at the direct
instigation of their respective Governments.
The next eclipse, that of May 6, 1883, had some dramatic features about
it. To begin with its duration was unusually long—nearly 5½ minutes, and
Mrs. Todd in her genial American style remarks:—“After the frequent
manner of its kind, the path lay where it would be least useful—across
the wind-swept wastes of the Pacific. But fortunately one of a small
group of coral islands lay quite in its line, and, nothing daunted, the
brave scientific men set their faces toward this friendly cluster, in
cheerful faith that they could locate there. Directed to take up their
abode somewhere on a diminutive island about which nothing could be
ascertained beforehand, save the bare fact of its existence at a known
spot in mid-ocean, the American observers were absent from the United
States more than three months, most of which time was spent in
travelling, 15,000 miles in all, with ten full weeks at sea. Their tiny
foothold in the Pacific was Caroline Island, a coral atoll on the
outskirts of the Marquesas group.”
In spite of the unattractive, not to say forbidding, character of the
place to which they would have to go, parties of astronomers went out
from England, France, Austria, and Italy, and although rain fell on the
morning of the day the sky became quite clear by the time of totality
and the observations were completely successful. One of the pictures of
the Corona obtained by Trouvelot, an observer of French descent, but
belonging to the American party, has been often reproduced in books and
exhibited the Corona in a striking form. How few were the attractions of
Caroline Island as an eclipse station may be judged from the fact that
the inhabitants consisted of only four native men, one woman, and two
children who lived in three houses and two sheds.
On September 8, 1885, there occurred a total eclipse, which was seen as
such in New Zealand, but the observations were few, and with one
exception, unimportant and uninteresting. A certain Mr. Graydon,
however, made a sketch which showed at one point a complete break in the
Corona so that from the very edge of the Moon outwards into space, there
was a long and narrow black space showing nothing but a vacuity. If this
was really the condition of things, such a break in the Corona is
apparently quite unprecedented.
In 1886, on August 29, there occurred a total eclipse, visible in the
West Indies, which yielded various important results. It was unfortunate
that for the greater part of its length, the zone of totality covered
ocean and not land, the only land being the Island of Grenada and some
adjacent parts of South America. The resulting restriction as regards
choice of observing stations was the more to be regretted because the
duration of the totality was so unusually long, and therefore
favourable, being more than 6½ minutes in the middle of the Atlantic
Ocean. Parties of English, American, and Italian astronomers assembled,
however, at Grenada, and though the weather was not the best possible,
some interesting photographs were obtained which exhibited an unusual
development of hydrogen protuberances. The central line in this eclipse
not only stretched right across the Atlantic, but entered Africa on the
West Coast where a missionary saw the eclipse as a mere spectator, and
afterwards expressed his regret that no astronomers were within reach
with instruments to record the remarkable Corona which was displayed to
his gaze.
Though the unusual opportunities which, so far as the Sun and the Moon
were concerned, were afforded by the eclipse of 1886 were lost,
astronomers looked out hopefully for August 19, 1887, when another
eclipse was due to happen which, weather permitting, would be observable
over a very long stretch of land, from Berlin through Russia and Siberia
to Japan. Unusually extensive preparations were made in Russia at one
end and in Japan at the other, but clouds prevailed very generally, and
the pictures of the Corona which were obtained fell far short in number
and quality from what had been hoped for, having regard to the number
and importance of the stations chosen, and of the astronomers who made
their preparations thereat. An enthusiastic Russian, in the hopes of
emancipating himself from the risks of terrestrial weather at the
Earth’s surface, went up in a balloon to an elevation of more than two
miles. His enthusiasm was so far rewarded that he had a very clear view
of a magnificent Corona; but as, owing to some mischance, the balloon
rose, conveying only the astronomer and leaving behind his assistant who
was to have managed the balloon, all his time was engrossed by the
management of the balloon, and he could do very little in the way of
purely astronomical work.
The year 1889 afforded two total eclipses of the Sun for which the usual
preparations were made. The first occurred on New Year’s Day, and the
path of the shadow crossed the North American Continent from California
to Manitoba. The weather was nearly everywhere very favourable, and an
enormous number of observers and instruments were assembled along the
central line. The consequence was that a very large number of
photographs were obtained. It may be said generally of this eclipse,
that as it coincided with a Sun-spot minimum, it left us in a position
to learn very distinctly what are the characteristic features of a solar
Corona at a period which is one of rest and repose on the Sun, at least,
so far as regards visible Sun-spots.
The second eclipse of 1889 occurred on December 22, and should have been
visible off the northern coast of South America and on the West Coast of
Africa. Attempts were made to utilise the South American chances by
English and American parties, whilst a small expedition comprising
astronomers of both nations went to Cape Ledo in West Africa. The
African efforts failed entirely owing to clouds, but the South American
parties at Cayenne were successful. One very deplorable result, however,
arising out of the expedition to Cayenne was the illness and subsequent
death of the Rev. S. J. Perry, S.J., who was struck down by malaria and
died at sea on the return journey. None who knew Mr. Perry personally
could fail to realise what a loss he was both to astronomy generally and
to his own circle of friends particularly.
On April 16, 1893, there happened a total eclipse of the Sun, which was
successfully watched by a large number of skilled observers throughout
its entire length. Indeed it is believed that only one party was
unsuccessful. The line of totality started on the coast of Chili, passed
over the highlands of that country, across the borders of Argentina and
Paraguay, and over the vast plains and forests of Central Brazil,
emerging at about noon of local time at a short distance to the N.-W. of
Ceara on the North Atlantic seaboard. Crossing the Atlantic nearly at
its narrowest part, it struck the coast of Africa N. of the river
Gambia, and finally disappeared somewhere in the Sahara. The South
American observations were the most extensive and successful, the latter
fact being due to the circumstance that the sky at many of the principal
stations was pre-eminently favourable, owing to the clearness and
dryness of the atmosphere.
On Sept. 29, 1894, there was a total eclipse of the Sun, but as its
duration was brief and the zone of totality lay chiefly over the Indian
Ocean, practically nothing came of it.
Things seemed, however, much more promising for the total eclipse of
Aug. 9, 1896, and a very large number of observers went out to the North
of Norway hoping to catch the shadow at its European end, whilst a
yacht party went to Nova Zembla in the Arctic Ocean, and a few observers
travelled as far as Japan. So far as the very large number of would-be
observers who went from England to Norway were concerned, the eclipse
was a profound disappointment, for owing to bad weather practically
nothing was seen in Norway except on the West coast near Bodö, where the
weather was beautifully fine, but where no adequate preparations had
been made, because nobody believed that the coast would be free from
fog. Exceptionally fine weather prevailed at Nova Zembla, and the small
but select party who were kindly taken there by the late Sir G. B.
Powell, M.P., in his yacht, were very fortunate, and an excellent series
of photographs was secured. One important result obtained at Nova Zembla
was a full confirmation by Mr. Shackleton of Prof. Young’s discovery in
1870 of the “Reversing Layer,” a discovery which was long and vehemently
disputed by Sir Norman Lockyer. Fairly successful observations were made
of this eclipse in Siberia and Japan.
The last total eclipse of the Sun which has to be noticed as an
accomplished fact was the “Indian Eclipse” of Jan. 22, 1898, which was
very successfully seen by large numbers of people who went to India from
all parts of the world. As usual in all total eclipses of the Sun
nowadays, the photographers were very much to the front, and the
photographs of the inner Corona, taken by the Astronomer Royal, are
thought to have been probably the best that have yet been done. Amongst
the miscellaneous observations made, it may be mentioned that more stars
were seen during the second partial phases than during totality (a
circumstance which had been noticed by Don A. Ulloa as far back as
1778). It is stated also that a mysterious object was seen between Mars
and Venus by two officers of H.M.S. _Melpomene_, which was not put down
on the published chart as a star to be looked for. The identity of this
object has not been ascertained.
FOOTNOTES:
[Footnote 108: _Memoirs_, R.A.S., vol. x. p. 5.]
[Footnote 109: _L’Annuaire_, 1846, p. 303.]
[Footnote 110: _Month. Not._, R.A.S., vol. xx. p. 301; May 1860.]
CHAPTER XIV.
THE ELECTRIC TELEGRAPH AS APPLIED TO ECLIPSES OF THE SUN.
Amongst the auxiliary agencies which have been brought into use in
recent years, to enable astronomers the better to carry out systematic
observations of eclipses of the Sun, the electric telegraph occupies a
place which may hereafter become prominent. As it is not likely that
this little book will fall into the hands of any persons who would be
able to make much use of telegraphy in connection with eclipse
observations, it will not be necessary to give much space to the matter,
but a few outlines will certainly be interesting. When the idea of
utilising the telegraph wire first came into men’s minds, it was with
the object of enabling observers who saw the commencement of an eclipse
at one end of the line of totality, to give cautionary notices to
observers farther on, or towards the far end, of special points which
had been seen at the beginning of the totality, and as to which
confirmatory observations, at a later hour, were evidently very
desirable. It is obvious that a scheme of this kind depends for its
success upon each end (or something like it) of the line of totality
being in telegraphic communication with the other end, and this involves
a combination of favourable circumstances not likely to exist at every
occurrence of a total eclipse, and in general only likely to prevail in
the case of eclipses visible over inhabited territory, such as the two
Americas, Europe, and parts of Asia. This use of the telegraph was, I
think, first proposed as far back as 1878, by an American astronomer, in
connection with the total eclipse of that year. His proposal fell upon
sympathetic ears, with the result that arrangements were concluded with
the Western Union Telegraph Company of North America for the expeditious
forwarding of messages from northern stations on the eclipse line to
southern stations. Some attention was being given at that time to the
question of Intra-Mercurial planets, and it was thought that if by good
fortune any such objects were unexpectedly found at the northern
station, and observers at a southern station could be advised of the
fact, there might be a better chance of procuring an accurate and
precise record of the discovery. As it happened, nothing came of it on
that occasion, but the idea of utilising the telegraph having once taken
possession of men’s minds, it was soon seen what important possibilities
were opened up.
The want of telegraph organisation curiously made itself felt in the
Egyptian eclipse of 1882. It is stated in another chapter of this work
that during the total phase a comet was unexpectedly discovered. Now
comets sometimes move very rapidly (especially when they are near the
Sun), and had it been possible to have warned some observer to the E. of
Egypt to look out for this comet, and had he seen it even only a couple
of hours after it had been found in Egypt, some data respecting its
position might have been obtained which would have permitted a rough
estimate being formed of its movement through the heavens. Such an
estimate might have enabled astronomers to have hunted up the comet at
sunset or sunrise on the days immediately following the eclipse. As it
happened, however, the comet was not seen again in 1882, and, so far as
we know, may never be seen again.
It was not till 1889 that a complete organisation of a telegraph service
in connection with an eclipse was accomplished. The eclipse of January 1
of that year began in the Pacific and the line of totality touched land
in California, passing across North America to Manitoba. The first
Californian station was at Willows, and was occupied by a party from
Harvard College Observatory, who were supplied with an unusually
complete equipment of photographic apparatus, together with a large
camera for charting all the stars in the neighbourhood of the Sun, so as
to detect an Intra-Mercurial planet if one existed. The telegraph scheme
which had to be worked out was somewhat complicated, and one of the
chief actors in the scene has furnished a fairly full account of what
was done. First of all, a complete list of the instruments and of the
work proposed to be done by them had to be prepared. The weather
probabilities being everywhere very unsatisfactory, there was a
possibility of all degrees of success or failure, and one thing which
had to be prearranged for each station was a cypher code which should be
available for all the likely combinations of instruments, weather and
results. It was found that about one hundred words would suffice for the
necessary code, including words which would indicate in a sufficiently
precise manner the position of any new planet which a photograph might
disclose.
The following, being a part of the code prescribed for use at Willows,
will serve to indicate the nature of the whole scheme:—
_Africa_, Perfectly clear throughout the whole eclipse.
_Alaska_, Perfectly clear during totality.
_Belgium_, Clear sky for the partial phases, but cloudy for totality.
_Bolivia_, Entirely cloudy throughout the whole eclipse.
_Brazil_, Observed all the contacts.
_Bremen_, Observed three of the contacts.
_Ceylon_, Made observations on the shadow-bands.
_Chili_, Observed lines of the reversing layer visually.
_China_, The Corona showed great detail.
_Cork_, Obtained 40-50 negatives during totality.
_Corsica_, Obtained 50-60 negatives during totality.
_Crimea_, Obtained 60-70 negatives during totality.
_Cuba_, Observed a comet.
Upwards of twenty codes were prepared for the like number of stations,
and the observers were to report their results at the earliest possible
moment. On a rehearsal of the programme the thought occurred that the
sending and reception of so many cypher messages in the ordinary course
of business might lead to delays which would be productive of serious
inconvenience, and that the success of the whole scheme could be only
well assured if a special wire, in direct circuit from New York to the
eclipse stations in turn, could be dedicated to the work. Thanks to the
liberality of the Western Union Telegraph Company this privilege was
secured, and a branch wire was led across from the Company’s New York
office to the office of the _New York Herald_, which journal had
undertaken to be responsible for the non-astronomical part of the
business.
Mrs. Todd gives the following account of the final arrangements, and of
how they began to work when the moment for action arrived:—“From San
Francisco every California observer was within easy telegraphic reach,
and the wire thus extended by direct circuit to each eclipse station in
turn. From the editorial rooms of the _Herald_ Professor Todd was in
immediate communication with any observers whom he chose to call. As
previously intimated, arrangements had been made with the Harvard
astronomers at Willows to receive their message first and with the
utmost despatch, in order to test the feasibility of outstripping the
Moon. Shortly before 5 o’clock in the afternoon despatches began to come
in. Of course a slight delay was unavoidable, as the observers at the
various stations were some rods distant from the local telegraph
offices, and it would take a few minutes after the eclipse was over to
prepare the suitable message from the cypher code. On the astronomer’s
table in the _Herald_ office were a large map and a chronometer. The
latter indicated exact Greenwich time, and the former showed the correct
position of the Moon’s shadow at the beginning of every minute by the
chronometer. In this way it was possible to follow readily the precise
phase of the eclipse at every station. About the rooms and accessible
for immediate use were arranged the cypher codes pertaining to the
several stations and other papers necessary in preparing the reports for
the press. Everything being, as was supposed, in working order, New York
about a quarter of an hour before totality commenced inquired of Willows
the state of the weather. The answer was that the sky was getting dark,
and that there were no clouds anywhere near the Sun. At that time the
Moon’s shadow was travelling across the open waters of the Pacific. It
rapidly rushed along; totality came and went at Willows; a two minutes’
glimpse of the Corona was had, and the Corona swept rapidly eastwards.
After a brief interval Professor Pickering sent off from Willows a
telegram which began—“_Alaska_, _China_, _Corsica_,” and then the
connection failed. The break was located somewhere between California
and Utah, and more than half an hour elapsed ere the circuit was
re-established, and the rest of the message received. The remainder of
the thrilling incidents of that eventful day cannot possibly be better
told than in Mrs. Todd’s crisp and striking language[111]:—
“During this interval the lunar shadow, advancing over Montana and
Dakota, had left the Earth entirely, sweeping off again into space.
Still, however, the prospect that the telegraph might win the race was
hopeful. Had New York been located in the eclipse path as well as
Willows, with both stations symmetrically placed, the total eclipse
would have become visible at New York about an hour and a quarter after
the shadow had left California. Thus there was time to spare. Having
recovered the wire, Professor Pickering’s message was completed at
10h. 36m. [G.M.T.], the cypher translated, and the stenographer’s notes
were written out and despatched to the composing-room six minutes later.
The “copy” was quickly put in type, and the hurried proof handed to
Professor Todd at 10h. 50m., exactly an hour of absolute time after the
observations were concluded. Had the Moon’s shadow been advancing from
California toward New York, there was still a margin of several minutes
before the eclipse could become total at the latter place. In point of
fact, while the proof sheet of the first message was being read, the
lunar shadow would have been loitering among the Alleghanies. Man’s
messenger had thus outrun the Moon. The telegraphic reports of the other
astronomers were gradually gathered and put in type, and the forms of
the _Herald_ were ready for the stereotyper at the proper time, some
two hours after midnight. At 3 o’clock a.m. the European mails closed,
and the pouches put on board the steamship _Aller_ carried the usual
copies for the foreign circulation. Within twenty-four hours after the
observations of the eclipse were made near the Pacific coast, the
results had been telegraphed to the Atlantic seaboard, collected and
printed, and the papers were well out on their journey to European
readers.”
The foregoing narrative will make amply clear the future possibilities
of telegraphy as a coadjutor of Astronomy in the observation of total
eclipses of the Sun. And if the will and the funds are forthcoming, the
eclipse of May 28, 1900, will afford an excellent opportunity of again
putting to the test the excellent ideas of which our American friends
worked out so successfully ten years ago. The zone of totality in that
eclipse passing as it will through so many of the densely populated
Southern States of North America, and then through Portugal, Spain, and
Algiers, great facilities will present themselves for telegraphic
combinations, if political and financial difficulties do not interfere.
FOOTNOTES:
[Footnote 111: There is a want of uniformity in Mrs. Todd’s
references to times which I have not thought it necessary to put
straight. “Greenwich Mean Time,” “Eastern U.S. Standard Time,” and
“Pacific Time,” are all severally quoted in happy-go-lucky
confusion.]
CHAPTER XV.
ECLIPSES OF THE MOON—GENERAL PRINCIPLES.
In dealing with eclipses generally, but with more especial reference to
eclipses of the Sun, in a previous chapter, it was unavoidable to mix
up in some degree eclipses of the Moon with those of the Sun. There
are, however, distinctions between the two phenomena which make it
convenient to separate them as much as possible. Eclipses of the Moon
are, like those of the Sun, divisible into “partial” and “total”
eclipses, but those words have a different application in regard to
eclipses of the Moon from what they have when eclipses of the Sun are in
question. A little thought will soon make it clear why this should be
the case. A partial eclipse of the Sun results from the visible body of
the Sun being in part concealed from us by the solid body of the Moon,
and so in a total eclipse there is total concealment of the one object
by the other.
But when we come to deal with partial and total eclipses of the Moon,
the situation, is materially different. The Moon becomes invisible by
passing into the dark shadow cast by the Earth into space.
[Illustration: FIG. 13.—THEORY OF AN ECLIPSE OF THE MOON.]
Fig. 13 will make this clear without the necessity of much verbal
explanation. S represents the Sun, E the Earth, and _mn_ the orbit of
the Moon. It is obvious that whilst the Moon is moving from _m_ to _n_
it becomes immersed in the Earth’s shadow. But before actually reaching
the shadow the Moon passes through a point in its orbit at which it
begins to lose the full light of the Sun. This is the entrance into the
“penumbra” (or “Partial shade”). Similarly, after the eclipse, when the
Moon has emerged from the full shadow it does not all at once come into
full sunshine, but again passes through the stage of penumbral
illumination,[112] and under such circumstances (to speak in the style
of Old “Oireland”) the invisible Moon is very often not invisible, and
the part partially eclipsed is often not eclipsed, and when the Moon is
totally eclipsed it is frequently still visible. Of course the general
idea involved in all cases of a body passing into the shadow of another
body is that the body which so passes disappears, because all direct
light is cut off from it. In the case, however, of a lunar eclipse this
state of things is not always literally accomplished, and very often
some residual light reaches the Moon (of course from the Sun) with the
result that traces of the Moon may often be discerned. The laws which
govern this matter are very ill-understood. The fact remains that if we
examine a series of reports of observed eclipses of the Moon extending
over many centuries (and records exist which enable us to do this) we
shall find that in some instances when the Moon was “totally” eclipsed
in the technical sense of that word, it was still perfectly visible,
whilst during other eclipses it absolutely and entirely disappeared from
view. Such eclipses are sometimes spoken of as “black” eclipses of the
Moon, but the phrase is not a happy one. Many instances of both kinds
will be found mentioned in the chapter on historical lunar
eclipses.[113]
[Illustration: FIG. 14.—CONDITIONS OF ECLIPSES OF THE MOON.]
The different conditions of eclipses of the Moon are illustrated by Fig.
14 which must be studied with the aid of the remarks made in a former
chapter concerning the apparent movements of the Sun and Moon and their
nodal passages. Suffice it to state here that in Fig. 14 AB represents
the ecliptic, and CD the Moon’s path. The three black circles are
imaginary sections of the Earth’s shadow as cast when the Earth is in
three successive positions in the ecliptic. If when the Earth’s shadow
is near A the Moon should be at E, and in Conjunction with the Earth
the Moon will escape eclipse; if the Conjunction takes place with both
the Earth’s shadow and the Moon a little further forward, say at F, the
Moon will be partially obscured; but if the Moon is at or very near its
node, as at G, it will be wholly involved in the Earth’s shadow and a
total eclipse will be the result. In the case contemplated at G in the
diagram, the Moon is concentrically placed with respect to the shadow,
but the eclipse will equally be total even though the two bodies are not
concentrically disposed, so long as the Moon is wholly within the cone
of the Earth’s shadow.[114]
Just as in the case of the Sun so with the Moon there are certain limits
on the ecliptic within which eclipses of the Moon _may_ take place,
other (narrower) limits within which they _must_ take place, and again
other limits beyond which they _cannot_ take place. Reverting to what
has been said on a previous page[115] with respect to these matters when
an eclipse of the Sun is in question it is only necessary to substitute
for the word “Conjunction,” the word “Opposition”; and for 18½° and 15¼°
of longitude the figures 12½° and 9¼°. The limits in latitude will be
1° 3′ and 0° 52′ instead of 1° 34′ and 1° 23′. These substitutions
made, the general ideas and facts stated with regard to the conditions
of an eclipse of the Sun will apply also to the one of the Moon.
It is to be noted that whereas eclipses of the Sun always begin on the
W. side of the Sun, eclipses of the Moon begin on the E. side of the
Moon. This difference arises from the fact that the Sun’s movement in
the ecliptic is only apparent (it being the Earth which really moves),
whilst the Moon’s movement is real.
Eclipses of the Moon, though more often and more widely visible than
eclipses of the Sun, do not offer by any means the same variety of
interesting or striking phenomena to the mere star-gazer, and it was
long thought that they were in a certain sense of no use to science.
Now, however, astronomers are inclined to utilise them for determining
the diameter of the Moon by noting occultations[116] of stars by the
Moon, the duration of a star’s invisibility behind an eclipsed Moon
being a measure of the lunar diameter when such an observation is
properly transformed and “reduced.” Observations of the heat radiated
(or rather reflected) by an eclipsed Moon have also been made with the
interesting result of showing that during an eclipse the Moon’s power to
reflect solar heat to the Earth sensibly declines.
The duration of an eclipse of the Moon is dependent on its magnitude.
Where the eclipse is total the darkness, or what counts for such, may
last for nearly 4 hours, though this is an extreme limit rarely
attained. An eclipse of from 6 to 12 digits (to use the old-fashioned
nomenclature which has been already explained) will continue from 2½ to
3½ hours. An eclipse of 3 to 6 digits will last 2 or 3 hours, and a
smaller eclipse only 1 or 2 hours. The visual observations to be made in
connection with partial or total eclipses of the Moon chiefly relate to
the appearances presented by our satellite when immersed in the Earth’s
shadow. On such occasions, as has been already stated, it frequently
happens that the Moon does not wholly disappear, but may be detected
either with a telescope or even without one. It may exhibit either a
dull grey appearance, or more commonly a pinkish-red hue to which the
designation “coppery” is generally applied. Perhaps the most remarkable
instance of this was the eclipse of March 19, 1848.
Mr. Forster who observed the phenomenon at Bruges thus describes[117]
what he saw:—“I wish to call your attention to the fact which I have
clearly ascertained, that during the whole of the late eclipse of March
19 the shaded surface presented a luminosity quite unusual, probably
about three times the intensity of the mean illumination of the eclipsed
lunar disc. The light was of a deep red colour. During the totality of
the eclipse the light and dark places on the face of the Moon could be
almost as well made out as on an ordinary dull moonlight night, and the
deep red colour where the sky was clearer was very remarkable from the
contrasted whiteness of the stars. My observations were made with
different telescopes, but all presented the same appearance, and the
remarkable luminosity struck everyone. The British Consul at Ghent, _who
did not know there was an eclipse_, wrote to me for an explanation of
the blood-red colour[118] of the Moon at 9 o’clock.”
In striking contrast to this stands the total eclipse of Oct. 4, 1884,
which is described by Mr. E. J. Stone[119] as “much the darkest that I
have ever seen, and just before the instant of totality it appeared as
if the Moon’s surface would be invisible to the naked eye during
totality; but such was not the case, for with the last appearance of the
bright reflected sunlight there appeared a dim circle of light around
the Moon’s disc, and the whole surface became faintly visible, and
continued so until the end of totality.”
A total eclipse of the Moon which happened on January 28, 1888, was
observed in many places under exceptionally favourable circumstances as
regards weather. The familiar copper colour is spoken of by many
observers. The Rev. S. J. Perry makes mention[120] of patches of colour
even as bright as “brick red, almost orange in the brighter parts,” and
this, 20 minutes before the total phase began. Mr. Perry conducted on
this occasion spectroscopic observations for the first time on an
eclipsed Moon, but no special results were obtained.
Various explanations have been offered for these diversities of
appearance. Undoubtedly they depend upon differences in the condition of
the Earth’s atmosphere, such as the unusual presence or unusual absence
of aqueous vapour; but it cannot be said that the laws which control
these diversities are by any means capable of being plainly enunciated,
notwithstanding that the explanation generally in vogue dates from as
far back as the time of Kepler. He suggested that the coppery hue was a
result of the refraction of the Earth’s atmosphere which had the effect
of bending the solar rays passing through it, so that they impinged upon
the Moon even when the Earth was actually interposed between the Sun and
the Moon. That the outstanding rays which became visible are red may be
considered due to the fact that the blue rays are absorbed in passing
through the terrestrial atmosphere, just as both the eastern and western
skies are frequently seen to assume a ruddy hue when illuminated in the
morning or evening by the solar rays at or near sunrise or sunset.
Owing to the variable meteorological condition of our atmosphere, the
actual quantity of light transmitted through it is liable to
considerable fluctuations, and no wonder therefore that variations occur
in the appearances presented by the Moon during her immersion in the
Earth’s shadow.
It has been suggested that if the portion of the Earth’s atmosphere
through which the Sun’s rays have to pass is tolerably free from aqueous
vapour, the red rays will be almost wholly absorbed, but not the blue
rays; and the resulting illumination will either only render the Moon’s
surface visible with a greyish blue tinge, or not visible at all. This
will yield the “black eclipse”—to recall the phrase quoted elsewhere.
If, on the other hand, the region of the Earth’s atmosphere through
which the Sun’s rays pass be highly saturated, it will be the blue rays
which suffer absorption, whilst the red rays will be transmitted and
will impart a ruddy hue to the Moon. Finally, if the Earth’s atmosphere
is in a different condition in different places, saturated in some parts
and not in others, a piebald sort of effect will be the result, and some
portions of the Moon’s disc will be invisible, whilst others will be
more or less illuminated. Further illustrations of all these three
alternatives will be found amongst the eclipses of the Moon recorded in
the chapter[121] devoted to historical matters.
A few instances are on record of a curious spectacle connected with
eclipses of the Moon which must have a word of mention. I refer to the
simultaneous visibility of the Sun and the Moon above the horizon, the
Moon at the time being eclipsed. At the first blush of the thing this
would seem to be an impossibility, remembering that it is a cardinal
principle of eclipses, both of the Sun and of the Moon, that the three
bodies must be in the same straight line in order to constitute an
eclipse. The anomalous spectacle just referred to is simply the result
of the refraction exercised by the Earth’s atmosphere. The setting Sun
which has actually set has apparently not done so, but is displaced
upwards by refraction. On the other hand, the rising Moon which has not
actually risen is displaced upwards by refraction and so becomes, as it
were, prematurely visible. In other words, refraction retards the
apparent setting of one body, the Sun, and accelerates the apparent
rising of the other body, the Moon. The effect of these two
displacements will be to bring the two bodies closer by more than 1° of
a great circle than they really are, this being the conjoint amount of
the double displacements due to refraction.
Amateur observers of eclipses of the Moon will find some pleasure, and
profit as well, in having before them on the occasion of an eclipse a
picture of the Moon’s surface in diagrammatic form with a few of the
principal mountains marked thereon; and then watching from time to time
(say by quarters of an hour) the successive encroachments of the Earth’s
shadow on the Moon’s surface and the gradual covering up of the larger
mountains as the shadow moves forward. The curved lines represent the
gradual progress of the shadow during the eclipse named. This diagram,
ignoring the curved lines actually marked on it, may be used over and
over again for any number of eclipses, simply noting from the _Nautical
Almanac_ or other suitable ephemerides the points on the Moon’s disc at
which the shadow first touches the disc as it comes on, and last touches
the disc as it goes off. The _Almanac_ indicates these points by
stating that the eclipse begins, or ends, as the case may be, at a point
which is so many degrees from the N. point of the Moon measured round
the Moon’s circumference by the E. or by the W. as the case may be.
One other point and we have disposed of eclipses of the Moon. The shadow
which we see creeping over the Moon during an eclipse is, as we know,
the shadow cast by the Earth. If we notice it attentively we shall see
that its outline is curved, and that it is in fact a complete segment of
a circle. Moreover that the circularity of this shadow is maintained
from first to last so far as we are able to follow it. What is this,
then, but a proof of the rotundity of the earth? This shape of the
Earth’s shadow on the Moon during a lunar eclipse was suggested as a
proof of the rotundity of the Earth by two old Greek astronomers,
Manilius and Cleomedes, who lived about 2000 years ago, and is one more
illustration of the great powers of observation and the general
acuteness of the natural philosophers of antiquity.
FOOTNOTES:
[Footnote 112: The time occupied by the Moon in passing through the
penumbra, before and after a lunar eclipse, will generally run to
about an hour for each passage. It will occasionally happen that the
Moon gets immersed in a penumbra but escapes the dark shadow. Such
an event will not be announced in the almanacs under the head of
“Eclipses.”]
[Footnote 113: See p. 197 (_post_).]
[Footnote 114: The shadow is spoken of as being in the form of a
cone because it is necessarily such on account of the light-giving
disc of the Sun being so enormously larger in diameter than the
light-receiving sphere of the Moon. This idea can be pursued by any
reader with the aid of a lamp enclosed in a glass globe and an
opaque sphere such as a cricket ball.]
[Footnote 115: See p. 19 (_ante_).]
[Footnote 116: As to occultations see chap. xxi. (_post_).]
[Footnote 117: _Month. Not._, R.A.S., vol. viii. p. 132. March,
1848.]
[Footnote 118: A very striking chromolithograph of the lunar
eclipses of Oct. 4, 1884, and Jan. 28, 1888, showing the contrast
of—(1) an almost invisible grey Moon, and (2) a reddish-pink Moon,
will be found in the German astronomical monthly, _Sirius_, vol.
xxi. p. 241. Nov. 1888.]
[Footnote 119: _Month. Not._, R.A.S., vol. xlv. p. 35.]
[Footnote 120: _Month. Not._, R.A.S., vol. xlviii. p. 227. March
1888.]
[Footnote 121: p. 197 (_post_).]
CHAPTER XVI.
ECLIPSES OF THE MOON MENTIONED IN HISTORY.
We saw in a previous chapter that we owe to the Chinese the first record
of an eclipse of the Sun. It must now be stated that the same remark
applies to the first recorded eclipse of the Moon, and Prof. S. M.
Russell is again our authority. He refers to a book called the
_Chou-Shu_ or book of the Chou Dynasty, said to have been found in 280
A.D. in the tomb of an Emperor who lived many centuries previously. In
this book it is stated that in the 35th year of Wen-Wang on the day
Ping-Tzu there was an eclipse of the Moon. Russell finds that this event
may be assigned to January 29, 1136 B.C., and that the eclipse was
total.
Next after this Chinese eclipse, in point of time, come several eclipses
recorded by Ptolemy, on the authority of records collected or examined
by himself. The three earliest of these came from Chaldæan sources.
The first of these eclipses was observed at Babylon, in the 27th year of
the era of Nabonassar, the 1st of the reign of Mardokempadius, on the
29th of the Egyptian month Thoth, answering to March 19, 721 B.C. The
eclipse began before moonrise, and the middle of the totality appears to
have occurred at 9h. 30m. p.m. The other two eclipses, also observed at
Babylon, occurred on March 8, 720 B.C., and September 1, in the same
year, respectively.
Three other lunar eclipses, recorded by Ptolemy, assisted Sir I. Newton
in fixing the _Terminus a quo_ from which the “70 weeks” of years were
to run which the prophet Daniel[122] predicted were to elapse before the
death of Christ. This _Terminus a quo_ dates from the Restoration of the
Jews under Artaxerxes, 457 B.C. The three eclipses which Newton made
use of were those of July 16, 523, November 19, 502, and April 25, 491
B.C.
Aristophanes, in “The Clouds” (lines 561-66), makes an allusion to which
has been supposed (but probably without adequate warrant, in Spanheim’s
opinion), to refer to an eclipse of the Moon. The eclipse, October 9,
425 B.C., has, moreover, been suggested as that referred to, but the
whole idea seems to me too shadowy.
An eclipse of the Moon took place in the 4th year of the 91st Olympiad,
answering to August 27, 413 B.C., which produced very disastrous
consequences to an Athenian army, owing to the ignorance and incapacity
of Nicias, the commander. The army was in Sicily, confronted by a
Syracusan army, and having failed, more or less, and sickness having
broken out, it was decided that the Athenians should embark and quit the
island. Plutarch, in his _Life of Nicias_, says:—“Everything accordingly
was prepared for embarkation, and the enemy paid no attention to these
movements, because they did not expect them. But in the night there
happened an eclipse of the Moon, at which Nicias and all the rest were
struck with a great panic, either through ignorance or superstition. As
for an eclipse of the Sun, which happens at the Conjunction, even the
common people had some idea of its being caused by the interposition of
the Moon; but they could not easily form a conception, by the
interposition of what body the Moon, when at the full, should suddenly
lose her light, and assume such a variety of colours. They looked upon
it therefore as a strange and preternatural phenomenon, a sign by which
the gods announced some great calamity.” And the calamity came to pass,
but only indirectly was it caused by the Moon!
Plutarch and Pliny both mention that eleven days before the victory of
Alexander over Darius, at Arbela in Assyria, there was an eclipse of the
Moon. Plutarch’s words (_Life of Alexander_) are, that “there happened
an eclipse of the Moon, about the beginning of the festival of the great
mysteries at Athens. The eleventh night after that eclipse, the two
armies being in view of each other, Darius kept his men under arms, and
took a general review of his troops by torch-light.” This seems to have
led to a great deal of disorderly tumult in the Assyrian camp, a fact
which was noticed by Alexander. Several of his friends urged him to make
a night attack on the enemy’s camp, but he preferred that his
Macedonians should have a good night’s rest, and it was then that he
uttered the celebrated answer, “I will not steal a victory.” Plutarch
enters upon some rather interesting moral reflections connected with
this answer, but which of course are foreign to the subject of this
volume. This eclipse happened on September 20, 331 B.C., and was total,
the middle of the eclipse being at about 8.15 p.m. It follows therefore,
that the celebrated battle of Arbela was fought on October 1, 331 B.C.
In 219 B.C. an eclipse of the Moon was seen in Mysia, according to
Polybius.[123] The date of September 1 has been assigned for this
eclipse which is said to have so greatly alarmed some Gaulish Mercenary
troops in the service of Attalus, King of Pergamos, that he had to get
rid of them as soon as he could—make terms with them to go home.
On the eve of the battle of Pydna when Perseus, King of Macedonia, was
conquered by Paulus Æmilius, there happened an eclipse of the Moon.
Plutarch in his _Life of Paulus Æmilius_, speaking of his army having
settled down in a camp, says:—“When they had supped and were thinking of
nothing but going to rest, on a sudden the Moon, which was then at full
and very high, began to be darkened, and after changing into various
colours, was at last totally eclipsed. The Romans, according to their
custom, made a great noise by striking upon vessels of brass and held up
lighted faggots and torches in the air in order to recall her light; but
the Macedonians did no such thing; horror and astonishment seized their
whole camp, and a whisper passed among the multitude that this
appearance portended the fall of the king. As for Æmilius, he was not
entirely unacquainted with this matter; he had heard of the ecliptic
inequalities which bring the Moon at certain periods under the shadow of
the Earth and darken her till she has passed that quarter of obscurity
and receives light from the Sun again. Nevertheless, as he was wont to
ascribe most events to the Deity, was a religious observer of sacrifices
and of the art of divination, he offered up to the Moon 11 heifers as
soon as he saw her regain her former lustre. At break of day he also
sacrificed oxen to Hercules to the number of 20 without any auspicious
sign, but in the twenty-first the desired tokens appeared and he
announced victory to his troops, provided they stood upon the
defensive.”
The astronomical knowledge ascribed in this account to Paulus Æmilius,
constitutes a very interesting feature in this record because the Romans
though they were good at most things, were by no means adepts at the
science of Astronomy. Livy[124] tells us that Sulpicius Gallus, one of
the Roman tribunes, foretold this eclipse, first to the Consul and then,
with his leave, to the army, whereby that terror which eclipses were
wont to breed in ignorant minds was entirely taken off and the soldiers
more and more disposed to confide in officers of so great wisdom and of
such general knowledge. This eclipse is often identified with that of
June 21, 168 B.C., but Johnson gives reasons why this cannot be the case
and that the eclipse in question was that which happened on the night of
June 10-11, 167 B.C., and commenced about midnight, whereas the eclipse
of 168 B.C. was nearly over when the Moon was above the horizon at Rome.
Stockwell, however, fixes on the eclipse of September 3, 172 B.C. as
that which was connected with the Battle of Pydna.
Josephus[125] speaking of the barbarous acts of Herod, says:—“And that
very night there was an eclipse of the Moon.” There has been some
controversy respecting the identification of this eclipse (the only one
mentioned by Josephus) which also is associated with Herod’s last
illness, it not having been easy to reconcile some discordant
chronological statements connected with the length of Herod’s reign and
the date when he began to reign. On the whole, probably, we shall be
safe in saying that the reference is to the eclipse of March 13, 4 B.C.
This was a partial eclipse to the extent of less than half the Moon’s
diameter, a defalcation of light sufficient, however, to attract public
notice even at 3 a.m., seeing that no doubt, even at that hour, the
streets of Jerusalem were in a state of turmoil owing to the burning
alive by Herod of some seditious Rabbis.
It should be stated, however, that Hind assigns the account by Josephus
to the eclipse which occurred on January 9, 1 B.C. On this occasion the
Moon passed nearly centrally through the Earth’s shadow soon after
midnight, emerging at 2.57 a.m. on the early morning of January 10,
local Mean Time at Jerusalem.
Tacitus[126] mentions an eclipse of the Moon as having happened soon
after the death of Augustus. This has been identified with the eclipse
of September 27, A.D. 14. Tacitus says:—“The Moon in the midst of a
clear sky became suddenly eclipsed; the soldiers who were ignorant of
the cause took this for an omen referring to their present adventures:
to their labours they compared the eclipse of the planet, and prophesied
‘that if to the distressed goddess should be restored her wonted
brightness and splendour, equally successful would be the issue of
their struggle.’ Hence they made a loud noise, by ringing upon brazen
metal, and by blowing trumpets and cornets; as she appeared brighter or
darker they exulted or lamented.”
There was an eclipse of the Moon on the generally recorded date of the
Crucifixion of our Lord, April 3, A.D. 33. Hind found that our satellite
emerged from the Earth’s dark shadow about a quarter of an hour before
she rose at Jerusalem (6h. 36m. p.m.), but the penumbra continued upon
her disc for an hour afterwards.
On Jan. 1, A.D. 47, a total eclipse of the Moon was seen at Rome, and on
the same night an island rose up in the Ægean Sea.
The total eclipse of Feb. 22, A.D. 72, noted by Pliny,[127] is the first
in which it is recorded that Sun and Moon were both visible at the same
time, the eclipse occurring when the Sun was rising and the Moon
setting.
Trithenius speaks of an eclipse of the Moon observed in the time of
Merovæus. Johnson identifies it with the eclipse of Sept. 15, 452 A.D.
It was from Merovæus that the line of French kings known as Merovingians
received their name.
On April 16, A.D. 683, according to Anastasius the Papal historian, the
Moon for nearly the whole night exhibited a blood-red appearance, and
did not emerge from obscurity till cockcrowing.
In A.D. 690 an eclipse of the Moon was observed in Wales. We are
told[128] that “the Moon was turned to the colour of blood.” This would
seem to be the first eclipse of the Moon recorded in Britain.
The _Anglo-Saxon Chronicle_ tells us that in A.D. 734 “the Moon was as
if it had been sprinkled with blood, and Archbishop Tatwine and Beda
died and Ecgberht was hallowed bishop.” The intended inference
apparently is that the Moon had something to do with the deaths of the
two ecclesiastics, but this theory will not hold water. Beda, it may be
remarked, is the correct name of the man generally known to us as the
“Venerable Bede.” It is evident that from the description of the Moon it
exhibited on that occasion the well-known coppery hue which is a
recognised feature of many total eclipses of our satellite. This eclipse
occurred on January 24, beginning at about 1 a.m.
On the night of January 23, A.D. 753, “the Moon was covered with a
horrid black shield.” This is the record of an eclipse. It occurred at
about midnight, and apparently we are entitled to infer that on this
occasion the Moon disappeared altogether, instead of being discoverable
during the total phase by exhibiting a coppery hue.
In A.D. 755 [or 756 in orig.], on November 23, there happened an
exceedingly interesting event which stands, I think, without a precedent
in the annals of science—an eclipse of the Moon contemporaneous with an
occultation of a planet by the Moon. This singular combination is thus
described in the annals of Roger de Hoveden[129]:—“On the 8th day
before the Calends of December the Moon on her 15th day being about her
full, appeared to be covered with the colour of blood, and then the
darkness decreasing she returned to her usual brightness; but, in a
wondrous manner, a bright star followed the Moon, and passing across
her, preceded her when shining, at the same distance which it had
followed her before she was darkened.” The details here given are not
astronomically quite correct, but let that pass; the writer’s intention
is fairly clear. Calculation shows that the eclipse occurred on November
23, and that the planet, which was Jupiter, was concealed in the evening
by the Moon for about an hour from 7h. 30m. to 8h. 30m. p.m., the
immersion taking place about the end of the total phase. This is the
first occultation of a star or planet by the Moon observed and recorded
in England.
Under the year 795 the _Anglo-Saxon Chronicle_ says:—“In this year the
Moon was eclipsed between cockcrowing and dawn on the 5th of the Calends
of April; and Eardwalf succeeded to the kingdom of the Northumbrians on
the 2nd of the Ides of May.” This signifies that the eclipse happened on
March 28 between 3h. and 6h. in the morning, the method of dividing the
hours of night into equal portions of three hours each being still in
use. There was no eclipse in 795 on the date in question but there was
one in 796, so we may suppose an error in the year. This assumed,
Johnson found that the eclipse began at about 4h. a.m., was total for
nearly an hour, and ended at about 7½h., so that the Moon set eclipsed.
But the above assumption is dispensed with by Lynn who substitutes one
of his own.[130] For “5th of the _Calends_” he reads “5th of the
_Ides_,” which means April 9; and on that day in 795 he says there was
an eclipse of the Moon, but I have not found any other record of it.
In the year A.D. 800, according to the _Anglo-Saxon Chronicle_, “the
Moon was eclipsed at the 2nd hour of the night (8h. p.m.) on the 17th
day of the Calends of February.” Johnson finds that there was an eclipse
of the Moon on Jan. 15. The middle of the eclipse occurred at 8h. 34m.,
9/10ths of the Moon’s upper limb having been obscured.
Under the date of 806 the _Anglo-Saxon Chronicle_ says:—“This year was
the Moon eclipsed on the Kalends [1st] of September; and Eardwulf, King
of the Northumbrians, was driven from his kingdom, and Eanberht, Bishop
of Hexham, died.” This eclipse was total, the totality lasting from
9h. 37m. to 10h. 59m. p.m.
On Feb. 15, 817, according to the _Annales Fuldenses_, an eclipse of the
Moon was observed in the early evening at Paris, and on the same night a
Comet was seen. This Comet is described by another authority as a
“monstrous” one and as being in Sagittarius on Feb. 5. The Chinese date
it for Feb. 17, and place it near the stars α and γ Tauri.
In 828 two lunar eclipses were seen in Europe, the first on July 1 very
early in the morning, and the second on the morning of Christmas Day.
The _Anglo-Saxon Chronicle_ thus speaks of the second eclipse:—“In this
year the Moon was eclipsed on Mid-winter’s Mass-night, and the same year
King Ecgbryht subdued the kingdom of the Mercians and all that was South
of the Humber.” The totality occurred after midnight. There is some
confusion in the year of this eclipse, the _Chronicle_ giving it as 827,
whilst calculation shows that it must have been 828. Lynn defines
“Mid-winter’s Mass-night” as Christmas _Eve_.
Under the date of 904 the _Anglo-Saxon Chronicle_ says:—“In this year
the Moon was eclipsed.” There were two total eclipses of the Moon this
year, one on May 31, and the other on Nov. 25, and it does not appear
which one is referred to in the _Chronicle_ cited. Another writer,
Cedrenus, speaks of a great eclipse of the Moon this year which he says
foretold the death of a kinsman of the Emperor.
On October 6, 1009, there was a total eclipse of the Moon which
presumably is referred to in the statement that “this year the Moon was
changed into blood.”
On Nov. 8, 1044, there was a large partial eclipse in the morning. Raoul
Glaber[131] (a French chronicler who died about 1050) comments upon it
thus:—“In what manner it happened, whether a prodigy brought to pass by
the Deity or by the intervention of some heavenly body, remains known to
the author of knowledge. For the Moon herself became like dark blood,
only getting clear of it a little before the dawn.” Truly those times
were the “Dark Ages” in which ignorance and folly were rampant, seeing
that more than 1000 years previously the Greeks knew all about the
causes of eclipses.
Under 1078 the _Anglo-Saxon Chronicle_ says:—“In this year the Moon was
eclipsed 3 nights before Candlemas, and Ægelwig, the ‘world-wide’ Abbot
of Evesham, died on St. Juliana’s Mass-day [Feb. 16]; and in this year
was the dry summer, and wildfire came in many Shires and burned many
towns.” Johnson found that a total eclipse of the Moon happened in the
early evening of Jan. 30.
On May 5, 1110, in the reign of Henry I., there occurred a total eclipse
of the Moon during which, says the _Anglo-Saxon Chronicle_, “the Moon
appeared in the evening brightly shining and afterwards by little and
little its light waned, so that as soon as it was night it was so
completely quenched that neither light nor orb nor anything at all of it
was seen. And so it continued very near until day, and then appeared
full and brightly shining. It was on this same day a fortnight old. All
the night the air was very clear, and the stars over all the heaven were
brightly shining. And the tree-fruits on that night were sorely nipt.”
The totality occurred before mid-night. It is evident that this was an
instance of a “black” eclipse when the Moon becomes quite invisible
instead of shining with the familiar coppery hue.
In 1117 there were two total eclipses, the first on June 16, and the
second on December 10. The latter is thus referred to in the
_Anglo-Saxon Chronicle_:—“In the night of the 3rd of the Ides of
December the Moon was far in [during a long time of] the night as if it
were all bloody, and afterwards eclipsed.” The totality commenced at
11.36 p.m.
It is recorded by Matthew Paris[132] in connection with the death of
Henry I. that “the Moon also was eclipsed the same year on the 29th of
July” [1135]. These words seem to indicate a total eclipse of the Moon.
Johnson gives the date as Dec. 22, 1135. If this is correct the text of
the _Chronicle_ must be corrupt. The whole eclipse was not visible in
England, the Moon setting before the middle of the eclipse. Stephen had
been crowned king the same day, namely Dec. 22.
On June 30, 1349, there was a total eclipse of the Moon visible at
London to which some interest attaches. Archdeacon Churton[133] connects
it with the following incident:—“The worthy Abp. Bradwardine, who
nourished in the reign of the Norman Edwards, and died A.D. 1349, tells
a story of a witch who was attempting to impose on the simple people of
the time. It was a fine summer’s night, and the Moon was suddenly
eclipsed. ‘Make me good amends,’ said she, ‘for old wrongs, or I will
bid the Sun also to withdraw his light from you.’ Bradwardine, who had
studied the Arabian astronomers, was more than a match for this simple
trick, without calling in the aid of the Saxon law. ‘Tell me,’ he said,
‘at what time you will do this, and we will believe you; or if you will
not tell me, I will tell you when the Sun or the Moon will next be
darkened, in what part of their orb the darkness will begin, how far it
will spread, and how long it will continue.’”
An eclipse of the Moon which happened when Columbus was at the Island of
Jamaica proved of great service to him when he was in difficulties owing
to the want of food supplies which the inhabitants refused to afford.
The eclipse was a total one, and so far as the description goes the
eclipses of April 2, 1493, and March 1, 1504, both respond to the
recorded circumstances: both were total and both occurred soon after
sunset. But, inasmuch as in the life of Columbus written by his son the
incident is placed nearly at the end of the work, there can be no doubt
that it is the later of the above eclipses which was the one in
question. The story is very graphically told by Sir A. Helps[134] in the
words following:—
“The Indians refused to minister to their wants any longer; and famine
was imminent. But just at this last extremity, the admiral, ever fertile
in devices, bethought him of an expedient for re-establishing his
influence over the Indians. His astronomical knowledge told him that on
a certain night an eclipse of the Moon would take place. One would think
that people living in the open air must be accustomed to see such
eclipses sufficiently often not to be particularly astonished at them.
But Columbus judged—and as the event proved, judged rightly—that by
predicting the eclipse he would gain a reputation as a prophet, and
command the respect and the obedience due to a person invested with
supernatural powers. He assembled the caciques of the neighbouring
tribes. Then, by means of an interpreter, he reproached them with
refusing to continue to supply provisions to the Spaniards. ‘The God who
protects me,’ he said, ‘will punish you. You know what has happened to
those of my followers who have rebelled against me; and the dangers
which they encountered in their attempt to cross Haiti, while those who
went at my command made the passage without difficulty. Soon, too, shall
the divine vengeance fall on you; this very night shall the Moon change
her colour and lose her light, in testimony of the evils which shall be
sent upon you from the skies.’
“The night was fine: the moon shone down in full brilliancy. But at the
appointed time the predicted phenomenon took place, and the wild howls
of the savages proclaimed their abject terror. They came in a body to
Columbus and implored his intercession. They promised to let him want
for nothing if only he would avert this judgment. As an earnest of their
sincerity they collected hastily a quantity of food and offered it at
his feet. At first, diplomatically hesitating, Columbus presently
affected to be softened by their entreaties. He consented to intercede
for them; and, retiring to his cabin, performed, as they supposed, some
mystic rite which should deliver them from the threatened punishment.
Soon the terrible shadow passed away from the face of the moon, and the
gratitude of the savages was as deep as their previous terror. But being
blended with much awe, it was not so evanescent as gratitude often is;
and henceforth there was no failure in the regular supply of provisions
to the castaways.”
Tycho Brahe observed a lunar eclipse on July 7, 1590. He writes:—“In the
morning about 3¾h. the Moon began to be eclipsed: in this eclipse it is
notable that both luminaries were at the same time above the horizon; a
like case which Pliny cites. For the centre of the Sun emerged when the
Moon was 2° elevated above the Western horizon, and when her centre was
setting, the centre of the Sun was elevated nearly 2°.”[135]
On August 16, 1598, there occurred a total eclipse of the Moon, observed
by Kepler,[136] in which during totality a part of the Moon was visible
and the rest invisible. He says, that while one-half of the disc was
seen with great difficulty the other half was discernible by a deep red
light of such brilliancy that at first he was doubtful whether our
satellite was immersed in the Earth’s shadow at all. This is an instance
of the simultaneous operation of those causes (whatever they may be)
which result in a totally-eclipsed Moon being sometimes wholly invisible
and sometimes entirely visible as a copper-coloured disc.
An eclipse of the Moon which happened on the morning of July 6, 1610,
may be mentioned as having been the first to be viewed through a
telescope. The eclipse was only a large partial one. The following
record of the fact is due to Tycho Brahe.[137] “The beginning of the
eclipse of the Moon as observed through the Roman telescope, appeared
like a dark thread in contact with the shadow”—a description which
cannot be said to be unduly explicit.
In 1620, on June 15, there was a total eclipse of the Moon, when during
the total phase “the Moon was seen with great difficulty. It shone,
moreover, like the thinnest nebula, far fainter than the Milky Way,
without any copper tinge. About the middle of the second hour nothing at
all could be seen of the Moon with the naked eye, and through the
telescope so doubtfully was anything seen that no one could tell whether
the Moon was not something else.” It is expressly stated, however, that
the sky was quite clear. Kepler also observed this eclipse, and says
that the Moon quite disappeared, though stars of the 4th and 5th
magnitudes were plainly visible.[138] In this same year 1620, there was
on December 9 another total eclipse, when “the Moon altogether
disappeared so that nothing could be seen of it, though the stars shone
brightly all around: she continued lost and invisible for a quarter of
an hour more or less.” This observation seems to have been made at
Ingolstadt.
Wendelinus mentions the eclipse of April 14, 1623, in connection with
the question of the visibility of the Moon when totally eclipsed. He
says, “but sometimes it so far retains the light derived from the Sun
that you would doubt whether any part of it were eclipsed.” This eclipse
was observed by Gassendi, and if the above record is correct, it is the
more remarkable seeing that the eclipse was not total, only 11/12ths of
the Moon’s diameter being obscured.
On April 25, 1642, on the occasion of a total eclipse, Hevelius[139]
noted that the Moon wholly disappeared when immersed in the Earth’s
shadow. Crabtree is stated by Flamsteed[140] to have observed this
eclipse, but he does not plainly state that he lost sight of the Moon.
Crabtree or his editor dates this eclipse for April 4; Ferguson for
April 15. There appears to be some muddle as between “old style” and
“new style.” Ferguson professing to be N.S. is evidently wrong. Hevelius
gives the double date, 15/25, which is evidently right.
On June 16, 1666, the Moon was seen in Tuscany to rise eclipsed, the Sun
not having yet set in the W.
On May 26, 1668, an eclipse of the Moon was in progress in the early
morning, when the Sun was seen to rise by members of the Academy of
Sciences who were observing the phenomenon at Montmartre near Paris.
On December 23, 1703, the Moon when totally immersed was seen at Avignon
showing a ruddy light of such brilliancy that we are told it had the
appearance of a transparent body illuminated by a light placed behind.
Johnson finds that the total phase took place in the early morning, and
lasted from 5h. 36m. to 7h. 22m. a.m.
The lunar eclipse of May 18, 1761, as observed by Wargentin,[141] at
Stockholm, furnishes a remarkable instance of the invisibility of the
Moon on certain occasions, when completely immersed in the earth’s
shadow. The total immersion of the Moon took place at 10h. 41m. p.m. The
part of the margin of the lunar disc which had last entered the shadow
was fairly conspicuous for 5 or 6 minutes after the immersion, and to
the naked eye exhibited a lustre equal to that of a star of the 2nd
magnitude; but at 10h. 52m. this part, as well as the whole of the rest
of the Moon’s body, “had disappeared so completely, that not the
slightest trace of any portion of the lunar disc could be discerned
either with the naked eye or with the telescope, although the sky was
clear, and the stars in the vicinity of the Moon were distinctly visible
in the telescope.” After more than half an hour’s search, Wargentin at
length discovered the whereabouts of the Moon by means of a faint light,
which was visible at the Eastern edge of the disc. A few minutes
afterwards, some persons of acute vision were able to discern, with the
naked eye, a trace of the Moon, looking like a patch of thin vapour, but
more than half the disc was still invisible.
An eclipse of the Moon, on March 29, 1801, was observed by Humboldt, on
board ship, off the Island of Baru, not far from Cartagena de las
Indias, in the Caribbean Sea.[142] He remarks that he was “exceedingly
struck with the greater luminous intensity of the Moon’s disc under a
tropical sky than in my native North.” Johnson makes Humboldt to refer
to the greater clearness of the “_reddened_ disc,” but these words do
not appear either in the German or in the English version.
A total eclipse of the Moon occurred on June 10, 1816. As observed by
Beer and Mädler and others, the Moon completely disappeared. The summer
of 1816, be it remembered, was very wet, and probably this had something
to do with the Moon’s invisibility at the eclipse in question.
On October 13, 1837, there happened a total eclipse of the Moon, of
which Sir J. Herschel and Admiral W. H. Smyth have left us interesting
accounts.[143] The changes of tint, both as regards times and places on
the Moon’s disc, recorded by the latter, are very remarkable. And the
tints themselves varied very much _inter se_: The Admiral speaks of
“copper,” “sea-green,” “neutral tint,” and “silvery,” as hues visible in
one part of the Moon or another, and at one time or another.
FOOTNOTES:
[Footnote 122: Dan. ix. 24.]
[Footnote 123: _Histories_, Book v., chap. lxxviii.]
[Footnote 124: _Hist. Rom._, Lib. xliv., cap. 37.]
[Footnote 125: _Antiq._, Lib. xvii., cap. 6, sec. 4.]
[Footnote 126: _Annales_, Lib. i., cap. 28.]
[Footnote 127: _Nat. Hist._, Lib. ii., cap. 3.]
[Footnote 128: _Annales Cambriæ_, Rolls ed., p. 8.]
[Footnote 129: _Annales_, Rogerus de Hoveden, Bohn’s ed., p. 5.]
[Footnote 130: _Observatory_, vol. xv. p. 224. May 1892.]
[Footnote 131: _Historiarum sui Temporis_, Lib. v., cap. 3.]
[Footnote 132: _Chronica Majora_, Rolls ed., edited by the Rev.
H. R. Luard, vol. ii. p. 161. Another version of this work is in
circulation under the name of Rogerus de Wendover, _Flores
Historiarum_. The passage here quoted appears in vol. i. p. 482,
Bohn’s ed.]
[Footnote 133: _History of the Early English Church_, 1870 ed., p.
271.]
[Footnote 134: _Life of Columbus_, p. 247.]
[Footnote 135: _Historia Cœlestis_, vol. i. p. xci.]
[Footnote 136: _Astronomiæ Pars Optica_, p. 276; _Opera Omnia_, vol.
ii. p. 302; Frisch’s edition.]
[Footnote 137: _Historia Cœlestis_, vol. ii. p. 921.]
[Footnote 138: _Epitomes Astronomiæ_, p. 825; _Opera Omnia_, vol.
vi. p. 482; Frisch’s edition.]
[Footnote 139: _Selenographia_, p. 117.]
[Footnote 140: _Historia Cœlestis_, vol. i. p. 4.]
[Footnote 141: _Phil. Trans._, vol. lii. p. 210. 1762.]
[Footnote 142: _Cosmos._ Trans. Sabine, vol. iii. p. 356; vol. iv.
p. 483. Bohn’s ed.]
[Footnote 143: _Cycle of Celest. Obj._, vol. i. p. 144; transcribed
in G. F. Chambers’s _Handbook of Astronomy_, vol. i. p. 329.]
CHAPTER XVII.
CATALOGUES OF ECLIPSES: AND THEIR CALCULATION.
This must of necessity be a brief chapter, so far as mere lines of text
are concerned, but it will not on that account be unimportant. It will
be evident to the reader that many more eclipses of interest have
happened, and will happen, than it has been possible to speak of in
these pages. Accordingly, as it is one of the main objects of this
series of volumes to create a thirst for knowledge, to be satisfied by
the study of other and bigger volumes, it will be desirable to furnish a
list of some of the various books and publications, in which eclipses
will be found catalogued or described in detail, so that readers
desirous of pursuing the matter further, may possess facilities for
doing so.
By far the most complete and comprehensive catalogue of solar eclipses
is that prepared some years ago by an Austrian astronomer, the late
Theodore Von Oppolzer of Vienna, and published under the title of _Canon
der Finsternisse_, in the Memoirs of the Imperial Academy of
Sciences.[144] This work supplies approximate calculations of about 8000
eclipses of the Sun, for a period of more than 3000 years, from November
10, 1207 B.C. (Julian Calendar), to November 17, 2161 A.D. (Gregorian
Calendar). There are appended 160 charts, of all the principal
eclipses; but as the charts only exhibit the beginnings, middles, and
ends of the eclipses dealt with, they are frequently misleading, because
the intermediate lines of path are, in many cases, more or less
considerably curved.
Another very important and comprehensive catalogue of eclipses, solar
and lunar together, will be found in the well-known French work, _L’Art
de vérifier les Dates_,[145] compiled by a member of the religious order
of St. Maur. One volume of this famous work contains eclipses from the
year 1001 B.C. to the Christian Era, whilst another volume gives a
similar catalogue from the year 1 A.D. to 2000 A.D. The other volumes
deal with chronological matters only. Although not strictly a work of
extreme astronomical exactness, yet _L’Art de vérifier les Dates_ stands
unrivalled as a record not only to subserve the purpose indicated by its
title, but of the bare facts of the eclipses which have happened during
the period of 3000 years stated above.
There has not been much done in England in the way of publishing eclipse
records or tables, past or future, but in the _British Almanac and
Companion_ for 1832 there is given a catalogue, which was useful in its
day, of eclipses, then future from 1832 to 1900, omitting, however,
solar eclipses hardly visible to any inhabited portion of the Earth, and
lunar eclipses where the part of the Moon’s diameter obscured was less
than 1/12th.
In by-gone days several attempts were made to gather together in a
tabular or paragraph form the details of eclipses which had happened,
and some of these have been important sources of information for the
guidance of us moderns. Foremost amongst these efforts must be named the
_Almagestum Novum_ of J. B. Ricciolus.[146] This work contains a
catalogue of eclipses observed from 772 B.C. to A.D. 1647, and continued
in tables to A.D. 1700. It is prefaced (pp. 286-8) by a long series of
quotations from classical authors relating to eclipses, some few of
which have already been mentioned in these pages.
Kepler paid much attention to eclipses, and left behind him a large mass
of notes and original observations. These will be found chiefly in his
_Astronomiæ Pars Optica_, c. vii. § 2, originally published at Frankfurt
in 1604. The most convenient and accessible edition of this is to be
found in Frisch’s reprint of all Kepler’s works.[147]
Tycho Brahe also gathered together from various sources many
observations of eclipses, and combined them with a number of his own,
the whole being published in his _Historia Cœlestis_.[148] Tycho Brahe
was a very interesting personage in spite of the fact that he went all
astray on the subject of the system of the Universe, and he well
deserves, what has been given to him, a book[149] all to himself. It is
peculiarly appropriate that I should give him a good word in this little
volume on eclipses, because it was the solar eclipse of Aug. 21, 1560,
which first seriously led him to take up astronomical pursuits, he being
then 14 years of age, and struck with wonder that eclipses could be
predicted.
A vast amount of historical and other information respecting eclipses
will be found in a book, the latinised name of whose author is Sethus
Calvisius. The title of the work is _Opus Chronologicum_.[150] The
historical matter is very much mixed, but the eclipses can be got hold
of through the Index, which is very full. P. Gassendi,[151] a well-known
astronomer of the 17th century, left behind him observations of many
eclipses observed by himself between 1628 and 1655. In a book entitled
_An Introduction to Universal Geography_,[152] one Nicolas Struyck in
the middle of the 18th century published a very full array of eclipse
observations collected with infinite pains from an endless variety of
authors ancient and modern.
In 1757 the well-known James Ferguson reprinted in his
_Astronomy_,[153] but in a very condensed form, all Struyck’s eclipses
from 721 B.C. to A.D. 1485. Then he carried on his catalogue to 1800 by
means of the materials furnished by Ricciolus and _L’Art de vérifier les
Dates_. Ferguson also invented a machine for illustrating mechanically
the circumstances of an eclipse. He called it the “Eclipsareon.” A full
description is given in his book, mentioned above, but I do not know
whether any such instrument is still in existence, or, if so, where it
is to be found.
Ferguson apologises[154] for the incompleteness of his eclipse
information in the following words:—“I have not cited one half of
Ricciolus’s list of portentous eclipses, and for the same reason that he
declines giving any more of them than what that list contains, namely,
that ‘tis most disagreeable to dwell any longer on such nonsense, and as
much as possible to avoid tiring the reader. The superstition of the
ancients may be seen by the few here copied. My author further says that
there were treatises written to show against what regions the malevolent
effects of any particular eclipse was aimed, and the writers affirmed
that the effects of an eclipse of the Sun continued as many years as the
eclipse lasted hours, and that of the Moon as many months.”
The most comprehensive (indeed almost the only) modern English book on
eclipses is the Rev. S. J. Johnson’s,[155] of which frequent use has
already been made in these pages. It contains a vast amount of matter
put together in a condensed form but the references to authorities are
rather defective and deficient. Less comprehensive in one sense yet
exceedingly valuable and interesting as a succinct summary of solar
eclipse knowledge up to the date of 1896 is Mrs. D. P. Todd’s excellent
little volume[156] which has been several times quoted on previous
pages. On various occasions in 1890 and following years Professor J. N.
Stockwell contributed to the American _Astronomical Journal_ a number of
papers[157] discussing in a very interesting and exhaustive manner many
of the eclipses recorded by the ancient classical authors. These papers
should be consulted by all who desire to realise the value of eclipse
records in connection with mundane chronology.
The calculation of eclipses is a matter of some interest. It is beyond
the scope of the present work to explain even in outline the methods in
use, but with the aid of the books mentioned below[158] a reader
possessed of the necessary time, mathematical knowledge, and patience,
will be able to pursue this matter as far as his inclination may lead
him. Johnson has found very useful the tables given in the eighth
edition of the _Encyclopædia Britannica_ (Article, “Astronomy”) but
strange to say these tables do not appear in ninth edition of that
famous work.
Lalande[159] has given numerous references to eclipses of the Sun during
the 16th, 17th and 18th centuries which may be useful to those who wish
to work at the history of eclipses.
FOOTNOTES:
[Footnote 144: _Denkschriften der Kaiserlichen Akademie der
Wissenschaften_, vol. lii. Vienna, 1887.]
[Footnote 145: There are several editions of this work in
circulation. The first (published in 1783) was in folio volumes,
but the best known edition is in a large number of octavo
volumes published in 1818 and following years. The eclipse lists
will be found in the 1st volumes of the first and second series
respectively. The French astronomer, Pingré, is responsible for
them.]
[Footnote 146: Published at Bononia (Bologna) in 1653.]
[Footnote 147: _Omnia Opera_, vol. ii. pp. 311-16. Edited by Ch.
Frisch. 8 vols. 8vo. Frankofurti-a-M., 1857-60.]
[Footnote 148: A collected edition of Tycho Brahe’s works, edited by
“Lucius Barettus,” was published at Augustæ Vindilicorum (Augsburg)
in 1666. Lucius Barettus is an anagram for the real name Albertus
Curtius.]
[Footnote 149: J. L. E. Dreyer, _Tycho Brahe: a Picture of
Scientific Life and Work in the Sixteenth Century_.]
[Footnote 150: _Opus Chronologicum._ Francofurti ad Mœnum, 1650.]
[Footnote 151: _Astronomica_, vol. iv. Lugduni, 1657.]
[Footnote 152: _Inleiding tot de Algemeene Geographie._ Amsterdam,
1740.]
[Footnote 153: _Astronomy Explained upon Sir Isaac Newton’s
Principles._ 2nd ed. 4to, pp. 167-79. London, 1757.]
[Footnote 154: _Astronomy_, p. 178.]
[Footnote 155: _Historical and Future Eclipses._ 2nd Ed., 1896.]
[Footnote 156: _Total Eclipses of the Sun._ Boston, U.S., 1894.]
[Footnote 157: _Astronomical Journal_, vol. x. pp. 25, 185; vol. xi.
pp. 5, 28, 57; vol. xii. p. 121; vol. xiii. p. 73; vol. xv. p. 73;
vol. xvi. pp. 89, 175.]
[Footnote 158: J. Ferguson. _Op. cit._; W. D. Snooke, _Brief
Astronomical Tables for the Expeditious Calculation of Eclipses_,
8vo. Lond. 1852.]
CHAPTER XVIII.
STRANGE ECLIPSE CUSTOMS.
I had intended heading this chapter “Eclipse Customs amongst Barbarous
Nations,” but in these days it is dangerous to talk of barbarians or to
speak one’s mind on points of social etiquette so I have thought it well
to tone down the original title, otherwise I should have the partisans
of the “Heathen Chinee” holding me up to scorn as a reviler of the
brethren.
Did space permit a very interesting record might be furnished of eclipse
customs in foreign parts.
An eclipse happened during Lord Macartney’s embassy to China[160] which
kept the Emperor and his Mandarins for a whole day devoutly praying the
gods that the Moon might not be eaten up by the great dragon which was
hovering about her. The next day a pantomime was performed, exhibiting
the battle of the dragon and the Moon, and in which two or three hundred
priests, bearing lanterns at the end of long sticks, dancing and
capering about, sometimes over the plain, and then over chairs and
tables, bore no mean part.
Professor Russell, who is quoted elsewhere in this work with respect to
Chinese eclipses, makes the following remarks in regard to what happens
now in China when eclipses occur:—“It will be interesting here to note
that, even at present, by Imperial command, special rites are performed
during solar and lunar eclipses. A president from each of the six
boards, with two inferior officials, dressed in their official clothes,
proceed to the T’ai-Ch’ang-Ssu. When the eclipse begins they change
their robes for common garments made of plain black material, and
kneeling down, burn incense. The president then beats one stroke on a
gong, and the ceremony is taken up by all the attendant officials.”
A writer in _Chambers’s Journal_[161] in an article entitled “The Hindu
view of the late Eclipse,” gives an interesting and original account of
divers Hindu superstitions and ceremonies which came under his notice in
connection with the total eclipse of the Sun of Aug. 18, 1868. He
remarks that “European science has as yet produced but little effect
upon the minds of the superstitious masses of India. Of the many
millions who witnessed the eclipse of the 18th of August last there were
comparatively few who did not verily believe that it was caused by the
dragon Rahu in his endeavour to swallow up the Lord of Day.... The
pious Hindu, before the eclipse comes on, takes a torch, and begins to
search his house and carefully removes all cooked food, and all water
for drinking purposes. Such food and water, by the eclipse, incur
_Grahana seshah_, that is, uncleanness, and are rendered unfit for use.
Some, with less scruples of conscience, declare that the food may be
preserved by placing on it _dharba_ or _Kusa grass_,” and much more to
the like effect is duly set out in the interesting article cited.
During the total eclipse of the Sun of Aug. 7, 1869, the following
incident is noted[162] to have occurred at a station on the Chilkaht
river, in Alaska, North America, frequented by Indians:—
“About the time the Sun was half obscured the chief Koh-Klux and all the
Indians had disappeared from around the observing tent; they left off
fishing on the river banks; all employments were discontinued; and every
soul disappeared; nor was a sound heard throughout the village of 53
houses. The natives had been warned of what would take place, but
doubted the prediction. When it did occur they looked upon me as the
cause of the Sun’s being ‘very sick and going to bed.’ They were
thoroughly alarmed, and overwhelmed with an undefinable dread.”
A still more thrilling incident is thus recorded[163] of the eclipse of
July 29, 1878, by a witness at Fort Sill, Indian Territory, U.S.:—
“On Monday last we were permitted to see the eclipse of the Sun in a
beautiful bright sky. Not a cloud was visible. We had made ample
preparation, laying in a stock of smoked glass several days in advance.
It was the grandest sight I ever beheld, but it frightened the Indians
badly. Some of them threw themselves upon their knees and invoked the
Divine blessing; others flung themselves flat on the ground, face
downward; others cried and yelled in frantic excitement and terror.
Finally one old fellow stepped from the door of his lodge, pistol in
hand, and fixing his eyes on the darkened Sun, mumbled a few
unintelligible words and raising his arm took direct aim at the
luminary, fired off his pistol, and after throwing his arms about his
head in a series of extraordinary gesticulations retreated to his own
quarters. As it happened, that very instant was the conclusion of
totality. The Indians beheld the glorious orb of day once more peep
forth, and it was unanimously voted that the timely discharge of that
pistol was the only thing that drove away the shadow and saved them from
the public inconvenience that would have certainly resulted from the
entire extinction of the Sun.”
A certain Mr. F. Kerigan, in a book published in 1844, made the
following remarks on ancient Jewish ideas respecting eclipses:—
“The Israelites, like their benighted neighbours, esteemed an eclipse of
either luminary as a supernatural and inauspicious omen, which filled
them with the most gloomy and fearful apprehensions: as may fairly be
deduced from the 8th chapter of Ezekiel, v. 15: ‘Then he brought me to
the door of the Lord’s House, which was towards the N.; and, behold
there sat women weeping for Tammuz.’ Now Tammuz is the name under which
Adonis was known in Palestine: he was the favourite of Venus, or
Astarte, the principal goddess of the Philistines and Phœnicians. Being
killed by a wild boar, the prevailing superstition of the age induced
the uninformed multitude to believe that when the Moon was eclipsed, it
was in complement to their beloved goddess Venus or Astarte, who,
concealed behind the full Moon, sat weeping under a dark veil for the
loss of her beloved Tammuz or Adonis.”[164]
The African travellers, R. and J. Lander, have given[165] a graphic
account of what took place on the occasion of the eclipse of the Moon of
Sept. 2, 1830, as witnessed by themselves:—“The earlier part of the
evening had been mild, serene, and remarkably pleasant. The Moon had
arisen with uncommon lustre, and being at the full, her appearance was
extremely delightful. It was the conclusion of the holidays, and many of
the people were enjoying the delicious coolness of a serene night, and
resting from the laborious exertions of the day; but when the Moon
became gradually obscured, fear overcame every one. As the eclipse
increased they became more terrified. All ran in great distress to
inform their sovereign of the circumstance, for there was not a single
cloud to cause so deep a shadow, and they could not comprehend the
nature or meaning of an eclipse.... Groups of men were blowing on
trumpets, which produced a harsh and discordant sound; some were
employed in beating old drums, others again were blowing on bullocks’
horns.... The diminished light, when the eclipse was complete, was just
sufficient for us to distinguish the various groups of people, and
contributed in no small degree to render the scene more imposing. If a
European, a stranger to Africa, had been placed on a sudden in the midst
of the terror-struck people, he would have imagined himself to be among
a legion of demons, holding a revel over a fallen spirit.”
FOOTNOTES:
[Footnote 159: _Bibliographie Astronomique._ Paris, 1803. Indexed at
p. 938.]
[Footnote 160: _Authentic Account of an Embassy to China_, by Sir G.
Staunton.]
[Footnote 161: Fourth Series, vol. v. p. 676. October 24, 1868.]
[Footnote 162: _Report U.S. Coast Survey_, 1869, p. 179.]
[Footnote 163: Letter published in the _Philadelphia Inquirer_.]
[Footnote 164: _A Practical Treatise on Eclipses_, p. 2.]
[Footnote 165: _Journal of an Expedition to Explore the Niger_, vol.
i. p. 366.]
CHAPTER XIX.
ECLIPSES IN SHAKESPEARE AND THE POETS.
The sound of these words may be large but facts do not bear out the
theory, for eclipses do not appear to have captivated our great poets to
anything like the extent that Moon, Stars, and Comets have done.
Shakespeare has a few allusions to eclipses, but they are not of prime
importance. In _Macbeth_ we find:—
“And slips of yew
Shivered in the Moon’s eclipse”
—Act iv. sc. 1.
the precise meaning of which is not very obvious. “Shivered” of course
means divided into pieces, but the idea intended is obscure.
The next quotation is more comprehensive and reflects more plainly the
current of thought prevalent in Shakespeare’s day, albeit here again the
word “eclipse” will be found to stand without much definite connection
with what goes before. However the reader shall judge for himself:—
“As stars with trains of fire and dews of blood,
Disasters in the Sun; and the moist star,
Upon whose influence Neptune’s Empire stands,
Was sick almost to doomsday with eclipse.”
—_Hamlet_, act i. sc. 1.
In _King Lear_ we seem to come upon something very definitely
historical, but I am not able to say what it is. The Earl of Gloster
says:—
“These late eclipses in the Sun and Moon portend no good to us.”
With this, Edmund, Gloster’s son, apparently agrees, for he exclaims:—
“These eclipses do portend these divisions.”
—Act i. sc. 2.
In _Othello_, the Moor of Venice himself, in a moment of excitement,
says:—
“O, insupportable! O, heavy hour!
Methinks it should be now a huge eclipse
Of Sun and Moon, and that the affrighted globe
Should yawn at alteration.”
—Act v. sc. 2.
In _Anthony and Cleopatra_ we find Anthony expressing what our
forefathers so often thought in connection with astronomical matters:—
“Alack, our terrine Moon is now eclipsed;
And it portends alone
The fall of Anthony!”
—Act iii. sc. 11.
Milton has an allusion to an eclipse of the Sun which possesses a
two-fold interest—intrinsic and extrinsic. The former feature will be
self-evident when the passage is read. The poet, in describing[166] the
faded splendour of the fallen archangel, compares him to the Sun seen
under circumstances which have temporarily deprived it of its normal
brilliancy and glory:—
“As when the Sun new-risen
Looks through the horizontal misty air
Shorn of his beams, or, from behind the Moon
In dim eclipse, disastrous twilight sheds
On half the nations, and with fear of change
Perplexes Monarchs.”
It has been well said by Dr. Orchard[167] that “this passage affords us
an example of the sublimity of Milton’s imagination and of his skill in
adapting the grandest phenomena of nature to the illustration of his
subject.”
What I alluded to in saying that extrinsic interest attached to this
quotation, is the fact that these lines might have caused the
suppression of the poem as a whole. Mrs. Todd puts the matter
thus:—“_Paradise Lost_ was begun probably in 1658, although not finished
until 1663, nor its thorough revision completed until 1665. The
censorship still existed, and Tomkyns (one of the chaplains through whom
the Archbishop gave or refused license), although a broader-minded man
than many of his day, found this passage especially objectionable. The
poem was allowed to see the light only through the interposition of a
friend of Milton. Upon such slender chances may hang the life of an
incomparable work of art! But it is easy to see that in the turbulent
days when Charles the Second had returned to power, after the death of
Cromwell, these lines should have been deemed dangerously suggestive, in
imputing to monarchs ‘perplexity’ and ‘fear of change.’”
Other allusions to eclipses by Milton will be found as follows:—
Through the air she comes,
“Lur’d with the smell of infant blood, to dance
With Lapland witches, while the labouring Moon
Eclipses at their charms.”
—_Paradise Lost_, Bk. ii. lines 663-6.
“So saying, he dismiss’d them; they with speed
Their course through thickest constellation held,
Spreading their bane; the blasted stars look’d wan,
And planets, planet-struck, real eclipse,
Then suffer’d.”
—_Paradise Lost_, Bk. x. lines 410-14.
“O dark, dark, dark, amid the blaze of Noon,
Irrecoverably dark, total eclipse,
Without all hope of day!”
—_Samson Agonistes_, Lines 80-2.
“It was that fatal and perfidious bark,
Built in th’ eclipse, and rigg’d with curses dark,
That sunk so low that sacred heart of thine.”
—_Lycidas_, Lines 100-2.
Pope, in the following lines, may be presumed to mean that the covering
up of the Sun by the Moon, during a total eclipse, results in the Moon
becoming visible, at the cost of the Sun’s disappearance:—
“For Envy’d wit, like Sol eclips’d, makes known
Th’ opposing body’s grossness, not its own.”
—_Essay on Criticism_, Lines 469-70.
I have not attempted to pursue this matter through the pages of our
modern poets, but it is not unlikely that Scott and Tennyson
(especially) would have something on the subject of eclipses.
FOOTNOTES:
[Footnote 166: _Paradise Lost_, Book i., lines 594-9.]
[Footnote 167: _The Astronomy of Milton_, p. 259.]
CHAPTER XX.
BRIEF HINTS TO OBSERVERS OF ECLIPSES OF THE SUN.
A few words (they must be few for lack of space) may usefully be added,
by way of advice, to persons proposing to choose a suitable locality at
which to station themselves for viewing a total eclipse of the Sun. To
begin with, of course they ought to get as close as possible to the
central line, say within 10 or 20 miles at the most; this matter
settled, the next important point is to find out where the duration of
the totality will be longest, coupled with the Sun at its maximum
elevation above the horizon (to escape the influence of mists and fogs).
No advice, properly so-called, can be given on these points, because
they depend on the special circumstances of every eclipse, and must be
ascertained _ad hoc_ from the _Nautical Almanac_.
In anticipation of a forthcoming eclipse, it is very important to know
beforehand the probabilities of weather. If the _locus in quo_ of an
expected eclipse is in a civilised country, there will generally not be
much difficulty in obtaining a certain amount of information as to this
6 or 12 months in advance. But inasmuch as total eclipses of the Sun,
and often the best of them, are visible only in uncivilised countries or
over trackless wastes, the problem becomes a complicated and anxious
one. In such cases it is exceedingly desirable, where competent
observers (including money) are available, that preliminary notes of
weather should be made for a year or even two years in advance. There is
in one sense no difficulty as to this, for all the mathematical local
elements of every eclipse are always made public three or four years in
advance through the pages of books like the _Nautical Almanac_, the
_Connaissance des Temps_, the _Berliner Jahrbuch_, &c. One difficulty
always confronts every eclipse expedition. If an out-of-the-way part of
the world has to be visited, accessible by sea, transport from England,
say, to the foreign shore is not usually a matter of difficulty, because
Government ships are often placed at the disposal of astronomers. But
the gravest difficulties often have to be faced after the arrival at the
foreign shore, and for this reason. Every sea coast is, as a general
rule applicable to the whole world, bad for astronomical observations.
The problem then which has to be solved is, how best to get away from
the coast inland to a high hill, and to find the means of transporting
thither heavy packing-cases of instruments, personal luggage, creature
comforts, and, if needs be, tents and the other accessories of camp
life. Let not the reader of either sex take fright at the idea of
sleeping under a tent. I speak with considerable experience when I say
that, given fine or fairly fine weather, nothing is more enjoyable in a
temperate climate. Under the term “creature comforts” I mean such things
as tinned soups and preserved provisions which nowadays can so easily be
purchased everywhere in England, and of such good quality. I would
recommend these being taken even when the eclipse traveller expects to
be lodged in the dwelling-places of civilised nations. Of course, if in
order to see his eclipse he has to go into the wilds of America, Asia,
or Africa, he must start fully equipped with all those personal
_impedimenta_ which will be found scheduled in the books mentioned in
the footnote.[168]
FOOTNOTES:
[Footnote 168: _The Tourists’ Pocket-Book_, 1s. (Philip); F.
Galton’s _Art of Travel_, 7s. 6d. (Murray); Royal Geographical
Society’s _Hints to Travellers_, 5s. (R. G. S., Savile Row). &c.]
CHAPTER XXI.
TRANSITS AND OCCULTATIONS.
No book professing to deal with eclipses would be complete without a few
words of mention of “transits” and “occultations.” A transit is the
passing of a primary planet across the Sun, or of a secondary planet
(_i.e._ satellite) across its primary, whilst an occultation is the
concealment of a star by the Moon, or of a secondary planet (_i.e._
satellite) by its primary. A little thought given to this definition
will make it clear that a transit is essentially the same in principle
as an eclipse of the Sun by the Moon—one body comes in front of another,
and the former conceals in succession parts of the latter.
Practically the word “transit” in this connection is more especially
applied to passages of the inferior planets, Mercury and Venus, across
the Sun, or of the satellites of Jupiter across the disc of Jupiter,
whilst the word “occultation” more particularly calls to mind the
concealment of a star (apparently a little body) by the Moon (apparently
a big body) or of a satellite of Jupiter (a little body) by Jupiter (a
big body), the star and the satellite in each respective case passing
behind the occulting body and being concealed for a shorter or longer
time. Commonly the occulted body will remain hidden for an hour or two,
more or less. In the case of Jupiter the satellites of that planet may
also, on occasions, be seen to undergo eclipse in the shadow cast by
Jupiter itself. An eclipse of a Jovian satellite is therefore on all
fours in principle the same as an eclipse of the Moon, caused, as we
know, by the Moon passing for a short time into the dark shadow cast by
the Earth. The conditions just laid down in respect of Jupiter and its
satellites also find a counterpart in the case of the satellites of
Saturn, but whilst these phenomena are incessantly occurring and visible
in the case of Jupiter, they are exceedingly rare in the case of Saturn
owing to its greater distance and the difficulty of seeing most of its
satellites because of their small apparent size.
Having regard to the circumstance that transits of Mercury and Venus
only happen at intervals of many years, it is not worth while for the
purposes of this work to devote any great amount of space to them. In
point of fact, whilst the next three transits of Mercury are as remote
as 1907, 1914 and 1924, there will be no transit of Venus at all during
the 20th century; not another indeed until A.D. 2004.
From the standpoint of an amateur astronomer the various phenomena which
attend the movements of the satellites of Jupiter, constitute an endless
variety of interesting scenes, which are the more deserving of attention
in that they can be followed with the aid of a telescope of very
moderate size and capabilities.[169]
[Illustration: FIG. 15-16.—OCCULTATION OF JUPITER, AUG. 7, 1889
(_Immersion_)]
Occultations of planets and stars by the Moon may also be recommended to
the notice of the owners of small telescopes as events which are
constantly happening and which may be readily observed. The Moon being
rapidly in motion it will happen in point of fact that stars are
occulted by it, one may say every day, but of course the Moon’s light
entirely blots out the smaller stars and only those as large as, say,
about the 5th magnitude are as a rule worth trying to see in this
connection. A table of the occultations of such stars, copied from the
_Nautical Almanac_, will be found in such almanacs as _Whitaker’s_ and
the _British_. If such a table is consulted it will be found that never
does a lunation pass without a few stars being noted as undergoing
occultation, and now and then a planet. An occultation of a planet is
obviously still more interesting than that of a star.
[Illustration: FIG. 17-18.—OCCULTATION OF JUPITER, AUG. 7, 1889
(_Emersion_).]
From the epoch of New to Full Moon the Moon moves with its dark edge
foremost from the epoch of Full to New with its illuminated edge
foremost. During therefore the first half of a lunation the objects
occulted disappear at the dark edge and reappear at the illuminated
edge, during the second half of a lunation things are _vice versâ_. The
most interesting time for watching occultations is with a young Moon no
more than, say, from 2 to 6 days old, because under such circumstances
the star occulted is suddenly extinguished at a point in the sky where
there seems nothing to interfere with it.
FOOTNOTES:
[Footnote 169: For details as to these matters, see my _Handbook of
Astronomy_, 4th ed., vol. i. pp. 186-196.]
APPENDIX.
THE TOTAL ECLIPSE OF THE SUN OF MAY 28, 1900.
This Appendix deals solely with geographical and transport matters as to
which accurate information is not easily obtainable, the European _locus
in quo_ of the Eclipse being in the benighted and somewhat untravelled
countries of Portugal and Spain.
The intending Eclipse excursionist must first make his choice between
(practically) a journey of all sea or of all land. The several sea
routes are one and all very much cheaper than any possible land journey,
and almost as quick in point of time, with the minimum amount of
personal knocking about. But (some persons will say) sea is sea, and so
it is. On the other hand the land journey is exceedingly expensive; and
beyond France the trains are very incommodious as regards hours, speed,
and connections. Moreover, there being more frontiers than one to cross,
there are extra opportunities for Custom-house squabbles, and Spain
especially is famous for this sort of thing.
As the Eclipse shadow will strike Europe in Portugal and quit Europe in
Spain the intending traveller must first decide for himself whether he
will prefer to go to Portugal or Spain. This settled, he will have the
choice of several sea routes and, in particular, of two land routes. But
before considering these further it will be well to state what are the
chief of the various places which are available as observing stations
for mixed travelling parties of ladies and gentlemen who have no desire
to rough it in out-of-the-way parts of the country.
The line of central eclipse passes across the Peninsula diagonally from
N.W. to S.E. It enters Portugal on the coast not far from Oporto in
latitude 40° 50′ N., longitude 8° 38′ W. of Greenwich. It quits Spain on
the coast at Cape Santa Pola, not far from Alicante, in latitude 38° 13′
N., longitude 0° 30′ W. At Ovar in Portugal (pop. 11,000), 23m. S. of
Oporto the duration of the total phase will be 1m. 33½s., and the Sun’s
altitude at totality will be 42°. At Talavera de la Reina in Spain (pop.
9700) the duration will be 1m. 27½s., and the altitude 39°; whilst at
Alicante (pop. 40,000) the duration will be still less, 1m. 19s., and
the Sun’s altitude only 34°. The three towns of Ovar, Talavera and
Alicante are selected _Nautical Almanac_ Eclipse stations, for which
special calculations have been made.
Hotel accommodation may be had at all the foregoing places, Oporto,
Ovar, Talavera and Alicante, as will be stated later on, but the Hotels
at Ovar and Talavera are not of much account.
Other towns more or less handy for the central line are few in number,
and as a rule deficient in lodging accommodation conforming to the
English standard. Amongst such possible alternative places the
following may be named (in order of position from N.W. to S.E.) as
accessible by railway:—
VIZEU (pop. 7000; hotels, _Mabilia_, _Cadite_), on a branch of the Beira
Alta Railway 31m. from Santa Comba Dao Junction, which itself is 88m.
from Oporto.
MANGUALDE (pop. 3000), on the Beira Alta Railway, 115m. from Oporto, and
49m. from Pampilhosa Junction.
PLASENCIA (pop. 6000; hotel, _F. de Eusebio Sierra_), 6m. N. of the
station of that name on the Lisbon and Madrid Railway.
NAVALMORAL (pop. 3300, buffet), a station on the Lisbon and Madrid
Railway about 8m. W. of the central line of eclipse.
URDA, a small station on the Madrid and Ciudad Real Railway, crossed by
the central line. The nearest accommodation would seem to be at Ciudad
Real (pop. 14,000; hotel, _Baltasar Garcia_), 33m. to the S.
ALCAZAR DE SAN JUAN Junction (pop. 8400; good buffet; hotel, _Casa
Briseño_). Alcazar is 92m. S. of Madrid; the central line crosses the
railway about 15m. to the S. of the town.
TOBARRA (pop. 7500), a station on the Chinchilla and Cartagena Railway,
212m. S. of Madrid, and 115m. N. of Cartagena, lies about 6m. S. of the
central line.
NOVELDA (pop. 8000), a station on the Alicante and Madrid Railway, in a
beautiful valley about 20m. N. of Alicante.
In addition to the above places it must not be forgotten that both
Oporto at one end of the zone of totality and Alicante at the other are
within the track of the shadow, but the question of the meteorological
conditions of the atmosphere at these places (on the seaboard as they
virtually are) has to be considered.
A traveller from England to Portugal or Spain by sea has the following
choice of routes:—
1. _Southampton to Oporto_, fortnightly, on Fridays, by the steamers of
the “Royal Mail Steam Packet Co.” Fare, first-class return, about £11.
Time, about 54h. The return tickets are conveniently grouped in various
ways, _e.g._ Southampton to Oporto, and back from Vigo or Lisbon; or
Southampton to Lisbon and back, or back from Vigo (_but not back from
Oporto_). Where the booking is to Vigo, or Lisbon, of course the local
railway fares have to be paid in addition. Lisbon is 209m. S. of Oporto;
Vigo, 110m. N. of Oporto. One objection to making any use of Vigo is the
extra Custom-house formalities which have to be gone through on the
frontier, and Spanish Custom-house officials are specially
objectionable.
2. _Liverpool_ to _Corunna_, _Carril_, _Vigo_ and _Oporto_, fortnightly,
on Thursdays, by the steamers of the “Pacific Steam Navigation Co.”
Fares, to the Spanish ports, first-class single, £6, 10s., return, £9,
15s.; second-class single, £4. To the Portuguese ports, first-class
single, £8, return, £12; second-class single, £5. Time, about 4 to 5
days. This does not mean that the steamers are very slow, but they call
also at La Rochelle, in France.
3. _London_ (Irongate Wharf) to _Oporto_, at intervals of 3 weeks, on
Thursdays, by the steamers of the “General Steam Navigation Co.” Fares,
first-class single, £4 (no return tickets issued; no second-class). The
steamers of this line are inferior to all the others.
4. _London_ (Tilbury) to _Gibraltar_, weekly, on Thursdays, by the
“P. & O.” steamers. Fares, first-class single, £10, return, £16. Time, 4
to 5 days.
5. _London_ (Tilbury) and _Plymouth_ to _Gibraltar_, fortnightly, on
Fridays, by the steamers of the “Orient Co.” Fares and time the same as
the “P. & O.”
Travellers journeying to Oporto from England will probably not attempt
to do any more local sight-seeing than what can be readily accomplished
by simple railway trips in Portugal to or from Lisbon; but travellers
landing at Gibraltar will have it within their power to visit some of
the important towns of Southern Spain, such as Granada, Seville,
Cordova, Toledo, Cadiz, Malaga, &c.
An Eclipse excursionist who finds himself at Gibraltar, and who wishes
to avoid as much as possible land travelling in Spain by going on to
Alicante and stationing himself in that neighbourhood, must take
shipping locally at Gibraltar. There are Spanish steamer services from
Gibraltar, and Malaga, to Alicante.
An overland traveller to Spain (it is presumed that none such will go as
far as Portugal) has the choice of two routes to eclipse stations in
Spain, both starting from Paris:—(1) _viâ_ Bordeaux, Hendaye, Vittoria,
Burgos and Medina del Campo, to Madrid, and thence either W. to Talavera
(84m. from Madrid), or S. towards Alcazar de San Juan (92m. from
Madrid); (2) _viâ_ Lyons, Perpignan, Barcelona and Valencia to Alicante.
The character of the train service on the second of these routes is
almost prohibitive, so that it is almost a question of _viâ_ Madrid or
not at all.
The foregoing paragraphs will furnish the reader with an outline of the
whole problem of how to reach from England a suitable eclipse station in
the Peninsula. This outline will pave the way for further details as to
land journeys, which will be exhibited somewhat in the order of relative
complexity and expense, beginning with the simplest.
VIGO TO OPORTO.
Chief stations and distances from Vigo:—Redondela (8m.), Guillarey
Junct. (24m.), Tuy (26m.), Vianna (57m.), Famalicao Junct. (88m.),
Oporto (108m.).
VIGO (pop. 17,000; hotel, _Continental_) is an important commercial
centre with fine scenery all round. REDONDELA is one of the prettiest
towns in Spain, especially as viewed from the railway viaducts. At
GUILLAREY carriages may have to be changed for TUY, the last station in
Spain and a Custom-house. There is a fine cathedral at Tuy. The boundary
is formed by the river Minho, spanned by a magnificent bridge 400 yards
long, railway above and carriage road underneath. Crossing it the train
enters the Portuguese town of VALENÇA, where there is a strong fortress
and a custom-house. VIANNA (pop. 7000; hotel, _Central_). The river Lima
is here spanned by a double bridge (rail and road) 700 ft. long. From
FAMALICAO there is a loop line to Oporto running round the coast and
15m. longer than the main line. ERMEZINDE is the junction with the
Spanish line to Barca d’Alva, Salamanca and France.
OPORTO TO OVAR AND LISBON.
From Oporto to Lisbon by the direct line it is 211m. Fares—first,
single, £1, 11s.; second, single, £1, 3s. But forwards from Pampilhosa
(66m.) there is a loop line to Lisbon, running along the coast, and 25m.
longer than the direct line. If it is proposed to visit some of the
sights which will be mentioned presently, the coast line must be taken.
Chief stations between Oporto and Lisbon by the coast line:—Ovar (23m.),
Pampilhosa Junct. (66m.), Figueira da Foz (92m.), Leiria (132m.), Torres
Vedras (192m.), Lisbon, Rocio station, (236m.).
OPORTO (pop. 120,000; hotels, _Grande Hotel do Porto_, _Hotel de Paris_)
is a busy commercial city with much English colouring; _e.g._ church,
hospital, doctor, club, and full modern facilities for locomotion by
tramways, cabs and excursion carriages. The chief sights are:—(1)
Cathedral, (2) Bishop’s Palace, (3) Church of St. Francisco, (4) Palacio
da Bolsa, (5) Museu Portuense, (6) Museu Industrial, (7) Crystal Palace
and Gardens, (8) Bridge of Don Luiz I., and (9) Convent immortalised by
Wellington in 1809 when he made his celebrated “Passage of the Douro.”
The port for Oporto where the steamers from England load and discharge
is Leixões, about 4m. to the W., with a service of trains and trams into
the city.
OVAR.—This town being the nearest eclipse centre to England may be
expected to draw many travellers in 1900. Being only 22m. or 1½ hours
from Oporto, a day trip may be made thither from Oporto, and this will
suit the convenience of those who prefer for lodgings a large city to a
small provincial town. A train from Oporto at 7 a.m. returning at 7.45
p.m. will suffice for the requirements of all who will go armed only
with small instruments.
PAMPILHOSA JUNCTION (Good Hotel).—Within 10m. to the N.-E. of this
station is the first of the special sights which can be seen in
connection with the Oporto-Lisbon railway. Take the train from
Pampilhosa to Luzo (6m.), omnibus thence (½ hour) to Busaco (Good
Hotel), and see the battlefield, the site of one of Wellington’s least
successful victories. The panoramic views in all directions are superb.
The famous convent is now a Government School of Forestry. After seeing
Busaco progress may be made to FIGUEIRA DA FOZ (38m. from Luzo—Good
Hotel), where the tourist may pass the night, unless he prefers to stay
at Pampilhosa. Figueira is a seaside bathing-place of repute on a branch
line.
LEIRIA (pop. 3000, _Novo Hotel_).—Stay here two nights in order to have
the whole of the intervening day available for a circular tour by road
to the Dominican Monastery at Batalha (7m.), and to the Cistercian
Monastery at Alcobaça (13m. from Batalha, and also 13m. from Leiria).
The Batalha Monastery (built 1388-1515) is by common consent the finest
piece of architecture in Portugal. The Alcobaça Monastery, the largest
in the world, is of earlier date (1148-1222). The ch., 360 ft. long, is
the most interesting example of early Christian art in Portugal, whilst
the cloisters are reputed to be amongst the finest in Europe.
Refreshments must be taken by the traveller, for none can be procured
during the drive. Vallado is really the nearest station to Alcobaça
(3m.), but there is no sleeping accommodation there.
LISBON (pop. 250,000; hotels—_Braganza_, _Avenida_, and some adjoining
the railway station) owing to its great length from E. to W., and narrow
breadth from N. to S., is a less easy city to find one’s way in than
many other cities. This difficulty is aggravated by the want of leading
thoroughfares and an efficient system of street naming and numbering.
The sights are the usual ones of every large Continental city, such as
churches, museums, and picture galleries; _e.g._ the Church of San
Roque, the Church of San Vincente with its remarkable Royal Mortuary
Chapel, the church and convent at Belem, and the gardens of the Escola
Polytechnica. But a day should certainly be set apart for a trip to
Cintra (17m. by rail, trains about every hour). The town (pop. 5000,
hotel—_Lawrence’s_) is 1800 ft. above the sea. See the Royal or Moorish
Palace in the town, the beautiful Pena Palace and grounds, and the
gardens of Sir F. Cook at _Villa Montserrate_ (3m). These last are open
daily to visitors who write their names at the entrance lodge. About 15
miles from Cintra is Mafra, with a palace, convent, and church of
wonderful magnificence. An Eclipse excursionist planning a time-table
for sight-seeing between Oporto and Lisbon inclusive, and with the
intention of returning to England from Lisbon, must remember that the
Royal Mail Company’s boats only sail fortnightly (on Tuesdays or
Wednesdays) from Lisbon. The boats anchor in the river, and are reached
by a steam tender.
OPORTO TO PARIS.
This route for getting from or to possible eclipse stations in Northern
Spain or Portugal is set out on the supposition that a certain number of
Eclipse excursionists may wish to combine the Paris Exhibition with the
eclipse. There is an International Express from Oporto (and Lisbon)
every Tuesday and Friday, which does the journey to Paris in 40 hours,
but no one travelling for pleasure would use this train, especially as
much of the best scenery is traversed by night.
The journey should therefore be performed in sections, which may be made
up as follows:—
Miles.
Oporto to Salamanca _viâ_ Pampilhosa 269
Salamanca to Burgos 150
Burgos to Biarritz 186
Biarritz to Paris 493
Use should be made as far as possible of the International Express.
Where this is not done, and ordinary trains have to be taken, the delays
are interminable and the combinations most exasperating to an
Englishman. The hotel accommodation in all the smaller towns of Spain is
so universally bad that it is not easy to suggest what otherwise would
seem obvious, namely, how best to subdivide, at any rate, the first
three of the above sections.
The International Express has a connection with Lisbon, the main train
being made up or divided as the case may be at Pampilhosa Junction.
LISBON TO TALAVERA AND MADRID.
Observers who think they will be able to do better as regards a clear
sky inland in Spain than near either the coast of Portugal or that of
Spain will still find in many cases that Lisbon is their most convenient
port for landing.
The chief stations on this route are:—Entroncamento Junction (67m.),
Marvão (149m.), Valencia de Alcantara (159m.), *Plasencia (256m.),
*Navalmoral (287m.), *Talavera de la Reina (328m.), Madrid, Delicias
Stat. (412m.). The places marked (*) are all within the shadow track of
the eclipse.
ENTRONCAMENTO (Good Buffet) is the junction station for the lines N. to
Oporto and S.-E. to Badajos and most trains wait here: 8m. beyond, the
Tagus is crossed by a fine bridge commanding good views.
MARVÃO (Custom-house) is the last station in Portugal but the actual
frontier is 6m. further on. VALENCIA DE ALCANTARA (Custom-house) is the
first station in Spain. During the next 50m. the railway passes through
much wild mountain scenery.
PLASENCIA, NAVALMORAL, and TALAVERA as eclipse stations have been
mentioned on a previous page. Many celebrated struggles during the
Peninsular War took place in this part of Spain, notably at Talavera in
1809 and at Almaraz in 1812.
MADRID (pop. 470,000; _Hotel de Paris_, _Hotel de la Paix_).
GIBRALTAR TO MADRID (WITH EXCURSIONS, ON THE WAY, TO GRANADA AND
SEVILLE).
From Algeçiras (opposite Gibraltar) there runs every Wednesday an
International Express train to Madrid and Paris. The eclipse central
line crosses this route about 15m. S. of Alcazar de San Juan Junction
(pop. 8400; Good Buffet, Hotel, _Casa Briseño_) which is 368m. N. of
Algeçiras and 93m. S. of Madrid.
The chief stations between Algeçiras and Madrid are:—Bobadilla Junct.
(110m.), Cordova (185m.), Alcazar de San Juan (369m.), Aranjuez (430m.),
and Madrid (461m.).
Bobadilla is a double junction. A line runs thence E. to Granada
(75m.), and W. to Seville (104m.). A traveller visiting Granada must
return to Bobadilla to get to Seville, but from Seville he can rejoin
the main line at Cordova 75m. N. of Bobadilla, and avoid Bobadilla. From
Seville to Cordova is 81m.
Algeçiras is reached from Gibraltar by a local steamer. About one hour
is allowed to make the connection with the train. Eclipse travellers
going to this part of Spain who wish to take advantage of their
proximity to Granada and Seville will find the following time-table
usefully suggestive:—
May 16, W. Gibraltar to Granada, 8 a.m. to 8 p.m.
" 17, T. At Granada.
" 18, F. At Granada.
" 19, S. Granada to Seville, 7 a.m. to 6 p.m.
" 20, Sun. At Seville.
" 21, M. At Seville.
" 22, Tu. Seville to Cordova, 11 a.m. to 3 p.m.
" 23, W. At Cordova.
" 24, T. Cordova to Alcazar, 2 a.m. to 3 p.m.
" 25, F. At Alcazar.
" 26, S. At Alcazar.
" 27, Sun. At Alcazar.
" 28, M. Eclipse day.
Corresponding to the above International train there is an express from
Paris on Mondays reaching Algeçiras on Wednesdays. This, of course,
might suit the convenience of Eclipse travellers proposing to go to
Spain _viâ_ France, and perhaps return _viâ_ Gibraltar. The time
occupied by the International train between Paris and Algeçiras and
_vice versâ_ is about 49 hours.
LONDON TO ALICANTE.
The central line of the eclipse quits Spain at Cape Santa Pola about
10m. S. of Alicante (pop. 40,000): it crosses the line of the Alicante
and Madrid railway at Novelda (pop. 8000) a station about 20m. inland
from Alicante.
Alicante may be reached from England as follows:—(1) All sea, _viâ_
Gibraltar and Malaga; (2) all land, _viâ_ Paris, Biarritz and Madrid
(1077m.), or Paris, Lyons and Perpignan (1126m.); or (3) part land and
part sea, _viâ_ Paris and Marseilles, and thence by steamer to Barcelona
and Valencia.
As regards the two land routes there is not very much to choose except
that the Biarritz-Madrid route is somewhat shorter and much quicker than
the Perpignan-Barcelona route. As regards the two sea routes both are
probably bad from the standpoint of comfort, the steamers in which the
voyage would have to be completed being Spanish coasting vessels, but it
is difficult to obtain particulars of them in England.
The following are some of the chief places between Paris and Alicante on
the Perpignan route:—Dijon (195m.), Lyons (318m.), Avignon (461m.),
Nîmes (490m.), Perpignan (623m.), Spanish frontier at Port Bou (650m.),
Barcelona (758m.), Tarragona (825m.), Valencia (997m.), Alicante
(1126m.). The journey from Paris to Barcelona is accomplished in 23h. by
the International Express: the remaining 368 miles take 27 hours owing
to the bad connections of the trains.
Madrid is 285m. from Alicante, the journey occupying about 29h.
USEFUL BOOKS FOR PORTUGAL AND SPAIN.
As the result of much inquiry and research, the following may be
suggested:—
GUIDE-BOOKS.
_Handbook for Spain_, 2 vols. 20_s._ (J. Murray.)
_Handbook to Spain and Portugal_, Dr. Charnock. 7_s._ 6_d._ (W. J.
Adams.)
_Guide to Spain and Portugal_, O’Shea and Lomas. 15_s._ (A. & C. Black.)
_Handbook for Portugal._ 12_s._ (J. Murray.)
DICTIONARIES.
JÄSCHKE, R. _English-Spanish Conversation Dictionary._ 3_s._ 6_d._
(Nutt.)
CASTRO DE LA FAYETTE. _Novo Diccionario Inglez-Portugueze._ 2 vols.
6_s._
GRAMMARS AND PHRASE BOOKS.
D’ORSEY, Rev. A. J. D. _Colloquial Portuguese._ 3_s._ 6_d._ (Kegan
Paul.)
WALL, C. H. _Practical Portuguese Grammar._ 7_s._ (Nutt.)
THIMM, C. A. _Spanish Self-taught._ 1_s._ 6_d._ (Marlborough.)
_Spanish Conversation Book._ 1_s._ (Walter Scott.)
HUGO. _Spanish Simplified._ 2 Parts and Key. 1_s._ 6_d._ (1A Paternoster
Row.)
VARIOUS.
CHAMBERS, G. F. _The Tourist’s Pocket-Book._ [Vocabulary of 16
Languages]. 1_s._ (Philip.)
THIMM, C. A. _Spanish Washing Lists for both Sexes._ 6_d._
(Marlborough.)
[Illustration: DIAGRAM OF CONSPICUOUS STARS AND PLANETS LIKELY TO BE
VISIBLE DURING THE TOTAL ECLIPSE OF THE SUN, MAY 28, 1900.]
INDEX.
⁂ The Eclipses referred to in the Chapters on History (VIII.-XIII.) are
not, as regards dates, dealt with in this Index.
A.
Aberdour, Lord, 159.
Agathocles, The Eclipse of, 120.
Ahaz, Dial of, 90, 96, 101.
Airy, Sir G. B., 48, 74, 83, 84, 89, 110, 111, 113, 115, 123, 124, 144,
164, 167.
_Almanac, British_, 219.
_Almanac, Nautical_, 26, 35, 234, 238.
Ammianus Marcellinus, 133.
_Anglo-Saxon Chronicle_, 136, 137, 138, 142, 143, 146, 148, 205, 206,
207, 208, 209.
_Annales Fuldenses_, 143, 207.
Annular Eclipses of the Sun, 16.
Apollonius of Tyana, 130.
Arabian Records, 132, 138.
Arago, 125, 164.
Archilochus, 108.
Aristophanes, 199.
Ascending Node, 18.
Asser, 144.
B.
Baily, F., 57, 112, 122, 164.
“Baily’s Beads,” 57, 64, 164.
Barker, Sir R., 102.
Bede, 205.
Beer, 217.
Bible, Eclipses mentioned in, 86.
Biot, E., 80.
“Black” Eclipses of the Moon, 189.
Blackness of the Moon during Solar Eclipses, 43.
Blake, 48.
Boillot, 135.
Bosanquet, J. W., 91, 95, 101.
C.
Calvisius, 133, 137, 146, 221.
Carlini, 164.
Carrington, R. C., 60.
Cassini, 158.
Caussin, 139.
Cedrenus, 208.
Celoria, Prof., 150.
Chinese Eclipses of the Sun, 75.
—— of the Moon, 197.
Chromosphere, 60.
_Chronicon Scotorum_, 143.
Churton, Archdeacon, 210.
Cicero, 108, 109, 118.
Classical History, Eclipses mentioned in, 107.
Clavius, 64, 152.
Columbus, 211.
Confucius, 81.
Conjunction of the Moon, 31.
Copper colour of Moon in Lunar Eclipses, 192.
Corona, 56, 62, 105, 130, 144, 157, 159, 161, 168, 169.
Coronium, 69.
Crabtree, W., 215.
Crucifixion, The darkness at, 129.
D.
Delambre, 81.
De La Rue, W., 168.
De Louville, 158.
Descending Node, 18.
Dial of Ahaz, 90, 96, 101.
Digit explained, 28.
Diodorus Siculus, 120.
Diogenes Laërtius, 94.
Dion Cassius, 128, 130.
Draconic Month, 20.
Dreyer, J. L. E., 221.
Du Sèjour, 37, 39.
E.
Earthquakes and Eclipses, 75.
Earth-shine, 61.
Eclipsareon, Ferguson’s, 222.
Eclipse, Derivation of the word, 11.
——, number of in a year, 13.
—— of the Moon, 11.
—— of the Sun, 11.
——, Theory of, 15.
Eclipse of the Sun of May 28, 1900, 9, 40, 66, 71, 239.
Ennius, 118.
F.
Ferguson, J., 215, 221.
Ferrer, Don J., 163.
Flamsteed, J., 155, 215.
Florence of Worcester, 143.
Forster, 192.
Freeman, Prof. E. A., 146.
Full Moon, 13.
G.
Gassendi, P., 215, 221.
Gaubil, 80.
Gemma Frisius, 152.
Gilliss, Lieut. J. M., 168.
Ginzel, 75, 131.
Glaber, 145, 208.
Glycas, 92.
Grant, R., 131.
Graydon, 174.
Gregorius Turonensis, 135.
H.
Hagen, 163.
Halley, E., 148, 157.
Hansen’s Lunar Tables, 89, 118, 119, 124.
Helium, 69.
Helps, Sir A., 211.
Herodotus, 109, 114, 116.
Herschel, Sir J., 217.
Herschel, Sir W., 161, 162.
Hevelius, 215.
Hezekiah, King of Judah, 90.
Hinckes, Dr., 89.
Hind, J. R., 38, 80, 89, 115, 116, 125, 138, 142, 143, 147, 148, 151,
153, 154, 167, 203, 204.
Hitzig, 87.
Homer’s _Iliad_ quoted, 126.
Homer’s _Odyssey_ quoted, 94, 126.
Huggins, Sir W., 131.
Humboldt, A. Von, 133, 142, 217.
Hunter, W., 102.
I.
Ideler, 81.
J.
Janssen, 169.
Jesuit Missionaries in China, 81, 95.
Johnson, Rev. S. J., 38, 80, 128, 131, 133, 135, 137, 138, 142, 144, 145,
150, 202, 210, 216, 222.
Jones, Capt. F., 113.
Josephus, 202.
Justin, 121.
K.
Kepler, 64, 152, 153, 213, 214, 220.
Kerigan, F., 227.
Kirchoff, 69.
L.
Lalande, J. De, 224.
Lander, R. and J., 228.
Langley, Prof., 171.
Lardner, D., His _Hand-book of Astronomy_ cited, 12.
Lassell, W., 167.
Layard, Sir A. H., 113.
Leon of Corfu, 144.
Le Verrier’s Solar Tables, 89.
Lewis, Sir G. C., 110.
Liais, E., 44.
Limits, Lunar Ecliptic, 190.
Lingard, Dr., 150.
Livy, 125, 202.
Lockyer, Sir N., 178.
Lynn, W. T., 115, 131.
M.
Macartney, Lord, his Embassy to China, 224.
Maclaurin, 151, 153, 159.
Mädler, 217.
Magnitude of an Eclipse, 29.
Main, Rev. R., 88.
Maraldi, 158.
Matthew Paris, 210.
Maunder, E. W., 104, 106.
Meteorological effects of a solar eclipse, 54, 167.
Millosevich, 109.
Milton, J., 231.
Moon, Eclipses of, 186.
N.
_Nautical Almanac_, 26, 35, 234, 238.
Newcomb, S., 119, 127, 139, 144, 171.
Newcomb, S., His _Astronomy_ cited, 26.
New Moon, 13.
Newton, Sir I., 198.
Nicias, 199.
Nineveh Tablets, 89.
Nodes, 18, 19, 30.
O.
Occultations, 10, 12, 235, 237.
Ockley, S., 138.
Oltmanns, 112.
Oppolzer, T. Von, His _Canon_ cited, 35, 109, 218.
Opposition of the Moon, 31.
Orchard, Dr., 231.
P.
Partial Eclipses of the Sun, 17.
Pekin, Observatory at, 95.
Penumbra in Lunar Eclipses, 188.
Pepys, S., His _Diary_ cited, 155.
Perry, S. J., 177, 193.
Philostorgius, 134.
Philostratus, 130.
Pickering, E. H., 184.
Pingré, 219.
Planets, Primary, 12.
——, Secondary, 12.
——, Visibility of during Eclipses, 61.
Pliny, 126, 200, 204, 213.
Plutarch, _Lives_, 108, 115, 117, 120, 126, 131, 199, 200, 201.
Polybius, 200.
Pope, A., 94, 233.
Powell, Sir G. B., 178.
Prominences, 59.
Pusey, Dr. E. B., 87, 88.
R.
Rawlinson, Sir H. C., 88, 111.
Red Flames, 59, 156, 159, 168.
Ricciolus, J. B., 220, 222.
Roger of Wendover, 149, 210.
Roger de Hoveden, 205.
Rothmann, R. W., 77.
Rümker, 48.
Russell, S. M., 78, 79, 198, 225.
S.
Santini, 164.
“Saros,” The, 14, 18, 112, 157.
Schnurrer, 142.
Schuster, 172.
Season of Eclipses, 29.
Seneca, 126.
Shadow Bands, 46.
Shadow of Moon on Earth, 36, 41, 49, 73.
Shakespeare, W., 229.
Smith, J. D., 48.
Smyth, Admiral W. H., 217.
Short, J., 159.
Suetonius, 126.
Snooke, W. D., 223.
Spain, Eclipse of 1900 visible in, 10.
Spots on the Sun, 67, 69.
Stannyan, Capt., 60, 156.
Staunton, Sir G., 224.
Stockwell, J. N., 131, 202, 223.
Stone, E. J., 193.
“Stiklastad,” “Eclipse of,” 144.
Struve, O., 164.
Struyck, N., 221.
Stukeley, Dr. W., 157, 160.
T.
Tacitus, 203.
Telegraph, Electric, and Eclipses, 179.
“Thales,” “Eclipse of,” 103, 109, 123.
Thirlwall, Bishop, 116.
Thucydides, 117, 118.
Tibullus, 126.
Todd, Mrs. D. T., her _Total Eclipses_ cited, 25, 27, 50, 56, 65, 71,
136, 146, 173, 183, 223, 231.
Totality, Approach of, 49.
——, Darkness of, 53.
Transits, 10, 12, 235.
Trithenius, 204.
Trouvelot, 106.
Tycho Brahe, 137, 143, 150, 152, 213, 214, 220.
U.
Ulloa, Don A., 64, 161, 179.
Usher, Archbishop, 87.
V.
Valz, 164.
W.
Wallis, Dr., 155.
Wargentin, 216.
Wesley, W. H., 66.
William of Malmesbury, 145, 147.
Williams, J., 81, 82, 83, 85, 86.
Wolcott, Miss K. E., 106.
Wyberd, Dr., 154.
X.
Xenophon, 112, 113, 119.
Y.
Young, Prof., 178.
Z.
Zech, 119.
[Transriber’s Note: The table below lists all corrections applied to the
original text.
p. 014: [removed extra hyphen] more than 18-years -> 18 years
p. 023: Phillipines -> Philippines
p. 027: occuring at regular intervals -> occurring
p. 048: Rumker mentions that -> Rümer
p. 059: every sufficiently skilled obersver -> observer
p. 070: [added closing bracket] (SUN-SPOT MINIMUM.)
p. 154: [removed comma] Greenock and Elgin, were near
p. 217: in the Carribean Sea -> Caribbean
p. 227: A certain Mr F. Kerigan -> Mr. F. Kerigan
p. 230: [removed comma] As, stars with trains of fire
p. 241: Casa Brisẽno -> Briseño
p. 244: Vienna (57m.) -> Vianna
p. 249: [normalized] Plasentia (256m.) -> Plasencia
p. 250: Casa Brisẽno -> Briseño ]
*** End of this LibraryBlog Digital Book "The Story of Eclipses" ***
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