If a soap-bubble be blown up, and set under a glass, so that the motion
of air may not affect it, as the water glides down the sides and the
top grows thinner, several colors will successively appear at the top,
and spread themselves from thence down the sides of the bubble, till
they vanish in the same order in which they appeared. At length a black
spot appears at the top, and spreads till the bubble bursts.