SUDDEN PRODUCTION OF LIGHT.
Take a piece of dry and warm wood into a dark room, suddenly rend it asunder, and a flash of light will be perceived. The same effect may likewise be produced by suddenly snapping asunder a stick of sealing-wax in the dark.
Or, break a Prince Rupert’s drop, and electrical light will pervade the whole, so that its form will be distinctly visible in the dark. The light will appear, even if the experiment be made under water.