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SPECTROPIA;
OR,
SURPRISING SPECTRAL ILLUSIONS.
SHOWING
G H O S T S   E V E R Y W H E R E,
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.]

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INTRODUCTION.

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

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

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

J. H. BROWN.

Old Steyne, Brighton.

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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 aquarter of a minute, or while counting about twenty, the plate beingwell illuminated by either artificial or day light. Then turning theeyes to the ceiling, the wall, the sky, or better still to a white sheethung on the wall of a darkened room (not totally dark), and lookingrather steadily at any one point, the spectre will soon begin to makeits appearance, increasing in intensity, and then gradually vanishing,to reappear and again vanish; it will continue to do so several times insuccession, 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 theplate has been strongly illuminated.

Those who use gaslight will find it convenient, after having looked atthe plate as above described, to extemporise a darkened room by havingthe gaslight turned low; or one end of the room may be darkened byplacing a screen before the gas, la

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