Another Curious Experiment With Oil And Water

Drop a small quantity of oil into water agitated by the wind; it will

immediately spread itself with surprising swiftness upon the surface,

and the oil, though scarcely more than a tea-spoonful, will produce an

instant calm over a space several yards square. It should be done on

the windward side of the pond or river, and you will observe it extend

to the size of nearly half an acre, making it appear as smooth as a

loo ing-glass. One remarkable circumstance in this experiment is the

sudden, wide, and forcible spreading of a drop of oil on the surface

of the water; for if a drop of oil be put upon a highly polished

marble table, or a looking-glass, laid horizontally, the drop remains

in its place, spreading very little, but when dropped on water it

spreads instantly many feet round, becoming so thin as to produce the

prismatic colours for a considerable space, and beyond them so much

thinner as to be invisible, except in its effect in smoothing the

waves at a much greater distance. It seems as if a repulsion of its

particles took place as soon as it touched the water, and so strong as

to act on other bodies swimming on the surface, as straw, leaves,

chips, &c., forcing them to recede every way from the drop, as from a

centre, leaving a large clear space.