Title: Spectropia; or, Surprising Spectral Illusions - Showing Ghosts Everywhere, and of Any Colour
Author: Brown, J. H. Oswald
Language: English
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SPECTRAL ILLUSIONS ***



[Illustration: I

_Designed by J. H. Brown, and Published Decʳ. 19ᵗʰ. 1863, by Griffith &
Farran, Sᵗ. Paul’s Church Yard, London._]



                              SPECTROPIA;


                    SURPRISING SPECTRAL ILLUSIONS.

                                SHOWING

                          GHOSTS EVERYWHERE,

                          AND OF ANY COLOUR.


                            BY J. H. BROWN.


                           _FOURTH EDITION._


                             First Series.
                      WITH SIXTEEN ILLUSTRATIONS.


                                LONDON:
                         GRIFFITH AND FARRAN,
                   SUCCESSORS TO NEWBERY AND HARRIS,
                   CORNER OF ST. PAUL’S CHURCHYARD.
                      H. & C. TREACHER, BRIGHTON.
                               MDCCCLXV.

                   [_Entered at Stationers’ Hall._]



INTRODUCTION.


The following Illusions are founded on two well-known facts; namely, the
persistency of impressions, and the production of complementary colours,
on the retina.

The explanations are divided into two Parts. The FIRST consists of
directions for seeing the spectres. The SECOND, a brief and popular, as
well as a scientific, description of the manner in which the spectres
are produced, and is intended for the use of those who may wish to know
more of this subject than is contained in the first Part.

As an apology for the apparent disregard of taste and fine art in the
plates, such figures are selected as best serve the purpose for which
they are intended.

                                                           J. H. BROWN.

OLD STEYNE, BRIGHTON.



DIRECTIONS.


To see the spectres, it is only necessary to look _steadily_ at the dot,
or asterisk, which is to be found on each of the plates, for about a
_quarter_ of a minute, or while counting about twenty, the plate being
well illuminated by either artificial or day light. Then turning the
eyes to the ceiling, the wall, the sky, or better still to a white sheet
hung on the wall of a darkened room (not totally dark), and looking
rather steadily at any one point, the spectre will soon begin to make
its appearance, increasing in intensity, and then gradually vanishing,
to reappear and again vanish; it will continue to do so several times in
succession, each reappearance being fainter than the one preceding.
Winking the eyes, or passing a finger rapidly to and fro before them,
will frequently hasten the appearance of the spectre, especially if the
plate has been strongly illuminated.

Those who use gaslight will find it convenient, after having looked at
the plate as above described, to extemporise a darkened room by having
the gaslight turned low; or one end of the room may be darkened by
placing a screen before the gas, lamp, or candle light.

The spectres may be easily made to appear life-sized or colossal, by
having the plate _nearer_ the eyes while receiving the impression, and
by _increasing the distance_ between the observer and the surface
against which they are seen. As a general rule, the observer should be
about eight to twenty feet from the surface. When the spectres are seen
against opposite houses, the sky, and other distant surfaces, they will
appear colossal.

Should any one not be able to see the spectre’s features, the reason
will be, either that the eyes have been allowed to wander, or the head
to move, while looking at the plate.

Many persons will see some one coloured spectre better than the others,
in consequence of their eyes not being equally sensitive to all colours.

The colours in the plate will be found to reverse themselves in the
spectres, as explained elsewhere, the spectres always appearing of the
complementary colour to that of the plate from which it is obtained.
Thus, blue will appear orange, and orange blue, &c.



LIST OF THE PLATES.


PLATE I.

This winged figure of Victory will give a white spectre by artificial
light (rather green by daylight), the red wreaths green, the green roses
red, and the orange stars blue.


PLATE II.

This black figure will give a white spectre.


PLATE III.

This will give a dark spectre.


PLATE IV.

This green figure will give a red spectre.


PLATE V.

And this red figure will give a green spectre.


PLATE VI.

This orange figure will give a blue spectre.


PLATE VII.

And this blue figure an orange spectre.


PLATE VIII.

This purple hand will give a yellow spectre.


PLATE IX.

And this yellow figure of Victory will give a purple spectre.


PLATE X.

The face of this figure will come out green in the spectre, the garment
red, and the cloud white.


PLATE XI.

This black skeleton will make a white spectre.


PLATE XII.

This skeleton will also give a white spectre, with a yellow mantle.


PLATE XIII.

This figure and broom will give a yellow spectre, cloak and hat red, and
moon white.


PLATE XIV.

These figures will give green and yellow spectres.


PLATE XV.

This Cupid will give a rose-coloured spectre, with bow and arrow yellow.


PLATE XVI.

This is a rainbow with colours reversed, the spectre of which will be
found a good resemblance of nature, especially when seen on a cloudy
sky.

       *       *       *       *       *

The colours of the spectres produced by these figures will not only be
subject to a slight variation in different eyes, but also by the degree
in which the plates are illuminated while being looked at.



A POPULAR AND SCIENTIFIC DESCRIPTION.


It is a curious fact that, in this age of scientific research, the
absurd follies of spiritualism should find an increase of supporters;
but mental epidemics seem at certain seasons to affect our minds, and
one of the oldest of these moral afflictions--witchcraft--is once more
prevalent in this nineteenth century, under the contemptible forms of
spirit-rapping and table-turning. The modern professor of these
impostures, like his predecessors in all such disreputable arts, is bent
only on raising the contents of the pockets of the most gullible portion
of humanity, and not the spirits of the departed, over which, as he well
knows, notwithstanding his profane assumption, he can have no power.

One thing we hope in some measure to further in the following pages, is
the extinction of the superstitious belief that apparitions are actual
spirits, by showing some of the many ways in which our senses may be
deceived, and that, in fact, no so-called ghost has ever appeared,
without its being referable either to mental or physiological deception,
or, in those instances where several persons have seen a spectre at the
same time, to natural objects, as in the case mentioned by Dr.
Abercrombie, in his work on “The Intellectual Powers:”--“A whole ship’s
company were thrown into the utmost consternation, by the apparition of
a cook who had died a few days before. He was distinctly seen walking
ahead of the ship, with a peculiar gait, by which he was distinguished
when alive, from having one of his legs shorter than the other. On
steering the ship toward the object, it was found to be a piece of
floating wreck.”

A ghost, according to the general descriptions of those who fancy they
have been favoured with a sight of one, appears to be of a pale
phosphorescent white, or bluish white colour; usually indistinct, and so
transparent that objects are easily seen through it. When moving, it
glides in a peculiar manner, the legs not being necessary to its
locomotion.

All the senses are more or less subject to deception, but the eye is
pre-eminently so; especially in the case of individuals who are in ill
health, because the sensibility of the retina is then generally much
exalted, as is also the imagination.

We may divide the illusions to which the sense of sight is liable into
four kinds. First, mental, or those arising in the brain itself, and
only referred to the eye. Second, those produced by the structure of the
eye. Third, those arising from the impressions of outward objects on the
retina. Fourth, those produced by various combinations of the foregoing.
It is only the second and third we shall have occasion to touch upon.
But before we can well understand their nature, it will be necessary to
get a slight knowledge of the structure of the eye, and some idea
respecting the nature of light.

[Illustration: FIG. 1.]

With perhaps the exception of the ear, the eye is the most wonderful
example of the infinite skill of the Creator. A more exquisite piece of
mechanism it is impossible for the human mind to conceive. The annexed
diagram (Fig. 1) of a horizontal section of this organ will give a
better idea of its general structure than whole pages of letter-press.
It will be seen to consist of a globe of three envelopes or coats, which
are kept distended by three transparent humours or lenses: the aqueous
(_e_), the crystalline (_f_), and the vitreous (_g_). The outer coat
(_a_) is dense, white, and fibrous. In front of the eye it gives place
to a perfectly transparent one, called the cornea (_d_). The next coat,
the choroid (_b_), is vascular, very black on its internal surface, in
order that light falling on it through the pupil (_h_) may not be
reflected. The pupil is an opening through a diaphragm which is called
the iris (_i_), from its colour varying in different individuals. It has
the power of expanding and contracting the pupil, for the purpose of
regulating the supply of light to the retina (_c_), or third and last
coat which lies immediately on the choroid. It is transparent, very
complex, and the only part of the eye we shall carefully consider. The
following diagram (Fig. 2) represents a section of it magnified 250
diameters, _a_ is called the limitary membrane, and forms its innermost
surface, or that which is next the vitreous humour; _b_ consists of the
layer of optic nerve fibers; _c_ is a layer of grey nerve cells; _d_,
two layers in which the principal retinal blood-vessels are spread out;
_e_, two layers of granular matter; _f_, Jacob’s membrane, or layer of
rods and cones. Fig. 3 will give some idea of the supposed connexion
between these various parts, the same letters referring to the same
parts as in Fig. 2.

[Illustration: FIG. 2.]

[Illustration: FIG. 3.]

When a ray of light enters the eye, it passes through the humours or
lenses, and is formed by them into an image, on the choroid, of the
object looked at. The extremities of the rods and cones have the power
of appreciating the image there formed, and convey it up through the
ultimate parts of the retina (Fig. 2), thence along the optic nerve
fibres to the brain. We are inclined to regard the extremities of the
rods and cones as the true seat of perception, in consequence of
observing a considerable distance between the retinal blood-vessels and
the choroid, when performing Purkinje’s experiment.[A] This experiment
consists in passing a lighted candle slowly to and fro before the eyes,
at about two or three inches from the nose, when the retinal vessels
will exhibit themselves before the observer not unlike branching trees.
They may be seen by daylight, by passing the large teeth of an ordinary
comb slowly backwards and forwards before the eye, whilst looking on a
smooth sheet of paper, or upon the sky. Fig. 4 represents those of the
left eye, as seen by candlelight. The spot marked _k_ is the exact
centre of the retina. (The same letter marks the same spot in Fig. 1.)
It is the seat of most distinct vision. _j_ is the entrance of the optic
nerve (Figs. 4 and 1), from the centre of which the retinal artery will
be seen emerging and spreading over the entire retina; but in the
diagram that part only is represented which could be seen tolerably
distinct. The background to the artery appears of a pale red, except at
the part occupied by the optic nerve, where it is white.

[A] This distance can easily be perceived by getting an impression
on the retina, according to the “Directions,” page 4, and then, on
performing the above experiment, the arterial ramifications and the
central spot will be distinctly perceived to move over the spectral
figure.

[Illustration: FIG. 4.]

After this rapid glance at so complicated a structure, and bearing in
mind that some persons can see its several parts with vastly greater
facility than others, it cannot be a matter of surprise that individuals
not aware of these facts are, now and then--especially at night, and
when carrying a light about--startled by what they fancy an apparition,
but which is in reality nothing more than some part of the structures
above considered. A lady assures us that she saw the ghost of her
husband as she was going downstairs with a lighted candle in her hand.
The spot _k_, Fig. 4, when seen against a wall a few feet distant,
appears about the size of a human head, and wants very little to furnish
it with features. Figured paper on the wall, and a host of other things,
may supply them, or even the retinal artery, which often lends body and
limbs. (Fig. 5.)

[Illustration: FIG. 5.]

Besides the above-mentioned structures, there are others which may play
an important part in these illusions, especially the common _muscæ
volantes_, so called from their resemblance to flying flies. They
consist of cells and filaments, the _débris_ of the structures of the
eye, and float about in its humours. That some of them exist very near
the retina appears evident from the fact that, on placing the eyes close
to a gauze wire blind, distinct miniature images of parts of the gauze
will be seen in them. (Fig. 6.)

[Illustration: FIG. 6.]

We now pass on to consider some of the leading properties of Light.
There have been many theories propounded from time to time in order to
explain the various phenomena connected with this subject, but only one
accords well with all, and that is called the undulatory or vibratory
theory, which, from its numerous complications, will compel us to
confine ourselves to a consideration of that part only which is
necessary to our present use. This theory regards light as the
vibrations of an imponderable ether pervading all space, the number of
these vibrations varying in a given time for each of the three primary
colours--blue, yellow, and red--the greatest number producing blue, the
least red, and an intermediate number yellow, all other colours being
produced by the combination of these in various proportions. Any two of
the three primary colours mixed together makes the complementary colour
to the third, and the third is also complementary to it. Thus, blue and
yellow make green, which is the complementary colour to red; red and
blue make purple, complementary to yellow; yellow and red make orange,
complementary to blue. When the three primary colours are mixed
together, white is the result: so that when a ray of white light falls
upon a piece of paper, and all the vibrations are equally reflected, the
paper will appear white, and if they are all absorbed, it will appear
black; but, if the paper absorbs some and reflects others, it will
appear coloured. Thus, if it absorbs those producing red, it will appear
green, from the mixture of the vibrations producing blue and yellow; and
if it absorbs blue and yellow, and reflects red, then it will appear
red. In this manner any object we look at will appear of any particular
colour, according to which vibrations it absorbs and which it reflects.

The retina is so admirably constructed that it is susceptible of
different impressions of colour by these different vibrations, except in
the case of a few individuals, who are either blind to all colour, and
therefore see everything black or white, and their intermediate shades,
or who are blind to only one or two colours.

When we look steadily at a red object for a few seconds, that part of
the retina on which the image impinges begins to get less sensitive to
vibrations producing red, but more sensitive to those producing blue
and yellow; so that on turning the eye away from the red object, and
permitting a little white light to enter it, that part of the retina
which received the red image will, in consequence of its diminished
sensibility to that colour, and its exalted sensibility to blue and
yellow, be able to perceive the two latter colours best, and by their
mixture will give rise to a green image of the red object. The same
thing will be observed with all the other colours; the secondary image
or spectre always appearing of the complementary colour to the object
from which the impression is obtained.

The duration and vividness of these impressions on the retina vary
greatly in different individuals, and can be procured from almost any
object. A person may, after looking steadily, and as often happens,
unconsciously, for a short time at printed or painted figures, on paper,
porcelain, &c., see, on turning the head in some other direction, a
life-sized or colossal spectre (the spectre appears larger the greater
the distance of the surface against which it is seen), and there can be
little doubt but that many of the reputed ghosts originate in this
manner.

[Illustration: II

_Designed by J. H. Brown, and Published Decʳ. 19ᵗʰ. 1863, by Griffith &
Farran, Sᵗ. Paul’s Church Yard, London._]

[Illustration: III]

[Illustration: IV

_Designed by J. H. Brown, and Published Decʳ. 19ᵗʰ. 1863, by Griffith &
Farran, Sᵗ. Paul’s Church Yard, London._]

[Illustration: V

_Designed by J. H. Brown, and Published Decʳ. 19ᵗʰ. 1863, by Griffith &
Farran, Sᵗ. Paul’s Church Yard, London._]

[Illustration: VI

_Designed by J. H. Brown, and Published Decʳ. 19ᵗʰ. 1863, by Griffith &
Farran, Sᵗ. Paul’s Church Yard, London._]

[Illustration: VII

_Designed by J. H. Brown, and Published Decʳ. 19ᵗʰ. 1863, by Griffith &
Farran, Sᵗ. Paul’s Church Yard, London._]

[Illustration: VIII

_Designed by J. H. Brown, and Published Decʳ. 19ᵗʰ. 1863, by Griffith &
Farran, Sᵗ. Paul’s Church Yard, London._]

[Illustration: IX

_Designed by J. H. Brown, and Published Decʳ. 19ᵗʰ. 1863, by Griffith &
Farran, Sᵗ. Paul’s Church Yard, London._]

[Illustration: X

_Designed by J. H. Brown, and Published Decʳ. 19ᵗʰ. 1863, by Griffith &
Farran, Sᵗ. Paul’s Church Yard, London._]

[Illustration: XI

_Designed by J. H. Brown, and Published Decʳ. 19ᵗʰ. 1863, by Griffith &
Farran, Sᵗ. Paul’s Church Yard, London._]

[Illustration: XII

_Designed by J. H. Brown, and Published Decʳ. 19ᵗʰ. 1863, by Griffith &
Farran, Sᵗ. Paul’s Church Yard, London._]

[Illustration: XIII

_Designed by J. H. Brown, and Published Decʳ. 19ᵗʰ. 1863, by Griffith &
Farran, Sᵗ. Paul’s Church Yard, London._]

[Illustration: XIV

_Designed by J. H. Brown, and Published Decʳ. 19ᵗʰ. 1863, by Griffith &
Farran, Sᵗ. Paul’s Church Yard, London._]

[Illustration: XV

_Designed by J. H. Brown, Published Decʳ. 19ᵗʰ. 1863, by Griffith &
Farran, Sᵗ. Paul’s Church Yard, London._]

[Illustration: XVI

_Designed by J. H. Brown, and Published Decʳ. 19ᵗʰ. 1863, by Griffith &
Farran, Sᵗ. Paul’s Church Yard, London._]



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