This section is from the book "The Boy Mechanic Vol. 2 1000 Things for Boys to Do", by Popular Mechanics Co.. Also available from Amazon: The Boy Mechanic, Vol2: 1000 Things for Boys to Do.
Print some photographs in the usualway on printing-out paper, then fix them in a solution of 1 oz. hyposulphite of soda and 8 oz. of water, and wash them thoroughly. While the prints are still wet, immerse them in a saturated solution of bichloride of mercury. Be very careful to wash the hands and trays after using the mercury solution, as it is poisonous. When the print is placed in the mercury solution, the picture vanishes completely. Leave the prints in this bath just long enough for the image to disappear, and then wash and dry them thoroughly. Soak some clean blotting paper in the hyposulphite-of-soda solution and allow it to dry. You are now ready to perform the magic-photograph trick.
To cause the spirit photograph to appear, cut a piece of blotting paper the same size as the prepared print and moisten it, then hold the apparently blank piece of paper in contact with it. The picture will come out clear and plain, and if thoroughly washed out it will remain permanently.
Saturate a small piece of cotton batting in glue and wrap it around a nail, then place it in a hole previously made in a plaster wall. When the glue dries, the nail will remain permanently.