light; being induced by exhibition of fire in molten substances, as lac, gold etc.
"Fluidity is perceptible by external senses, sight and touch.
"In hail and ice, fluidity essentially subsists, but is obstructed by an impediment arising from an unseen virtue which renders the water solid.
Viscidity.
14. "Viscidity is the quality of clamminess and cause of agglutination. It abides in water only. In oil, liquid butter, etc., it results from the watery part of those liquids.
Sound.
"15. Sound is a peculiar quality of the ethereal element, and is to be apprehended by the hearing. It abides in that element exclusively and is its characteristic quality. Two sorts are distinguished: articulate and musical.
Theory of the Propagation of Sound.
"To account for sound originating in one place being heard in another, it is observed, that sound is propagated by undulation, wave after wave,
