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.