The Magic Picture

Take two level pieces of glass, (plate glass is the best,) about three

inches long and four wide, exactly of the same size; lay one on the

other, and leave a space between them by pasting a piece of card, or

two or three small pieces of thick paper, at each corner.



Join these glasses together at the edges by a composition of lime

slaked by exposure to the air, and white of an egg. Cover all the

edges of t ese glasses with parchment or bladder, except at one end,

which is to be left open to admit the following composition.



Dissolve, by a slow fire, six ounces of hogs'-lard, with half an ounce

of white wax; to which you may add an ounce of clear linseed oil.



This must be poured in a liquid state, and before a fire, between the

glasses, by the space left in the sides, and which you are then to

close up. Wipe the glasses clean, and hold them before the fire, to

see that the composition will not run out at any part.



Then fasten with gum a picture or print, painted on very thin paper,

with its face to one of the glasses, and, if you like, you may fix the

whole in a frame.



While the mixture between the glasses is cold, the picture will be

quite concealed, but become transparent when held to the fire; and, as

the composition cools, it will gradually disappear.