Curiosities of Science, Past and Present / A Book for Old and Young

by John Timbs

LATENT HEAT.

This extraordinary principle exists in all bodies, and may be pressed out of them. The blacksmith hammers a nail until it becomes red hot, and from it he lights the match with which he kindles the fire of his forge. The iron has by this process become more dense, and percussion will not again produce incandescence until the bar has been exposed in fire to a red heat, when it absorbs heat, the particles are restored to their former state, and we can again by hammering develop both heat and light.—R. Hunt, F.R.S.