If you drop oil or fat on water it spreads and breaks into variegated patterns as beautiful as snow-flake figures.
Have a vessel of pure cold water, still as possible. Let one drop of oil fall on the surface from about four inches height.
Lay a piece of glazed surface paper on the oil pattern, take it instantly off, place it on the surface of a plate of ink for a moment, remove and wash off the excess of ink, and you will have a black picture closely resembling a photograph. For red use cochineal or the aniline reds.
Pure sperm oil takes a minute to form a pattern; green rape oil is slower; Lucca oil three minutes; green olive one minute, &c. Oils can be mixed and tried.
The formation can be shown by the magic lantern, from which is removed its nozzle pipe for a shorter one, so as to form the oleographs properly, and yet leave room enough for a small pipe to be thrust between the nozzle and the trough containing the water on which swims the oil.
The lantern is turned back so that the chimney is horizontal; the hole is then perpendicular; on it is set a trough made of two plates of glass joined together, the upper, which has a hole in it, to be filled with water. On the nozzle is placed a prism, which reflects the picture on the screen.
XI.—AMUSING TRICKS WITH VARIOUS ARTICLES.
TO DIVIDE A HORSESHOE INTO SEVEN PIECES BY TWO CUTS.
Make a horseshoe of a slice of pear or apple, potato, &c., and cut off the long arms at A B. Range all in a row, and cut them across into seven pieces.