ferent liquids assume a spheroidal form at widely different temperatures, one may obtain some startling results. For example, liquid sulphurous acid is so volatile as to have a temperature of only 13° F. when in that state, or 19° below the freezing point of water, so that if a little water be dropped into the acid, it will immediately freeze and the pellet of ice may be dropped into the hand from the still red-hot disk. Even mercury can be frozen in this way by a combination of chemicals.
Through the action of this principle it is possible to dip the hand for a short time into melted lead, or even into melted copper, the moisture of the skin supplying a vapor which prevents direct contact with the molten metal; no more than an endurable degree of heat reaches the hand while the moisture lasts, although the temperature of the fusing copper is 1996°. The natural moisture of the hand is usually sufficient for this result, but it is better to wipe the hand with a damp towel.
In David A. Wells' Things not Generally Known, New York, 1857, I find a translation of an article by M. Boutigny in The Comptes
