It is well known that the vapors of mercury are very diffusive in their nature, and some quite singular experiments have been devised, based upon this knowledge, and upon the fact that the salts of silver and the chlorides of gold, platinum, iridium, and palladium are affected by these mercurial vapors.
If any one, for instance, should write upon a sheet of white paper with platinum chloride, no mark would be visible, as the liquid is quite colorless. If, however, the same sheet of paper should be held over a little mercury, the metal will be brought out on the paper in dark tints. This magical apparition of a figure or drawing on a sheet of paper which appears to be perfectly white is very astonishing to the spectator.
MAGICAL APPARITION OF A DRAWING ON WHITE PAPER.
Reversing the experiment, a no less marvelous result is obtained. At first expose the drawing or writing to the gases of mercury; the lines will become charged with mercury, and then by simply bringing the drawing in contact with a sheet of paper previously sensitized with a solution of platinum, the drawing will be reproduced, line for line, on the white paper.
Drawings made in this way give a charming effect, the tones being very soft and the lines distinct and clear.