By taking advantage of the fact that different 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 degrees F. when in that state, or 19 degrees 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 degrees. 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 Rendus, in which he notes that "the portion of the hands which are not immersed in the fused metal, but are exposed to the action of the heat radiated from its surface, experience a painful sensation of heat." He adds that when the hand was dampened with ether "there was no sensation of heat, but, on the contrary, an agreeable feeling of coolness." Beckmann, in his History of Inventions, Vol. II., page 122, says: In the month of September, 1765, when I visited the copper works at Awested, one of the workmen, for a little drink money, took some of the melted copper in his hand, and after showing it to us, threw it against the wall. He then squeezed the fingers of his horny hand close together, put it for a few minutes under his armpit, to make it sweat, as he said; and, taking it again out, drew it over a ladle filled with melted copper, some of which he skimmed off, and moved his hand backwards and forwards, very quickly, by way of ostentation. While I was viewing this performance, I remarked a smell like that of singed horn or leather, though his hand was not burnt. The workmen at the Swedish melting-house showed the same thing to some travellers in the seventeenth century; for Regnard saw it in 1681, at the copper-works in Lapland. My friend Quincy Kilby, of Brookline, Mass., saw the same stunt performed by workmen at the Meridan Brittania Company's plant. They told him that if the hand had been wet it would have been badly scalded.