plates had a convenient habit of slipping into the washing tank and there, according to the author, becoming utterly ruined; also we learn that many were ruined by being accidentally smudged by the photographer's finger. We should not, we fear, have a very high opinion of an operator who was in the constant habit of "smudging" negatives with his fingers so as to entirely spoil them, nor can we quite understand what brand of plates was used that "got spoiled by falling into the water."

From La Nature.
FIG. 17.—SPIRIT PICTURE.

From La Nature.
FIG. 18.—SPIRIT PICTURE.

It is not difficult to explain how these pictures were produced. There are quite a number of methods. With a weak-minded sitter, over whom the operator had complete control, the matter would be in no wise a difficult one. It would then only be necessary for the spirit, suitably attired for the occasion, to appear for a few seconds behind the sitter during the exposure and be taken slightly out of focus, so as not to appear too corporeal.

If, however, the sitter be of another kind, anxious to discover how it was done and on the alert for any deceptive practices, the method described would be rather a risky one, as he might turn round suddenly at an inconvenient moment and detect the modus operandi. In such a case it becomes necessary to find some other method where it would not be requisite for the "spirit" to make its appearance during the presence of the sitter.

FIG. 19.—SPIRIT PICTURE
DISTURBED SLUMBER

The ghostly image can be prepared upon the plate, either before or after the exposure of the sitter. The method is this: In a darkened room the draped figure to represent the spirit is posed in a spirit-like attitude (whatever that may be) in front of a dark background with a suitable magnesium or other artificial light thrown upon the figure, which is then focused in the "fuzzy-type" style; or, better still, a fine piece of muslin gauze is placed close to the lens which gives a hazy, indistinct appearance to the image. The exposure is made and the latent image remains upon the sensitive plate, which is again used to photograph the sitter. Upon developing we get the two images, the "spirit" mixed up with the figure. The spirit should be as indistinct as possible, as it will then be less easy for the subject to dispute the statement that it is the spirit-form of his dead and gone relative. Some amount of discretion in this part of the performance must be used, we fancy, otherwise the same disaster might happen as did to a spiritualist some little time ago. An elderly gentleman had come for a seance, and, after some mysterious maneuvers, the gentleman was informed that the spirit of his mother was there. "Indeed!" replied the old gentleman, somewhat astonished. "What does she say?" "She says she will see you soon," informed the medium. "You are getting old now and must soon join her." "Quite right," replied the old gentleman; "I am going round to her house to tea to-night."—Total collapse of spiritualist.

FIG. 20.—PHOTOGRAPH OF "SPIRITS."

Fluorescent substances, such as bisulphate of quinine, can also be employed. This compound, although almost invisible to the eye, photographs nearly black. If a white piece of paper be painted with the substance, except on certain parts, the latter only will appear white in the picture.