Page:The Natural History of Pliny.djvu/171

Chap. 106.] WONDEES OF FOUNTAINS AND EIYEES. 137 these other wonderful operations of nature ; that copper and lead sink when in a mass, but float when spread out^ ; and of things that are equally heavy, some will sink to the bot- tom, while others will remain on the surface" ; that heavy bodies are more easily moved in water^ ; that a stone from Scyros, although very large, will float, while the same, when broken into small pieces, sinks'* ; that the body of an animal, newly deprived of life, sinks, but that, when it is swelled out, it floats^ ; that empty vessels are drawn out of the water Tvith no more ease than those that are fulP ; that rain-water is more useful for salt-pits than other kinds of water ; that salt cannot be made, unless it is mixed with fresh water^ ; that salt water freezes with more difficulty^, and is more readily heated ^*^ ; that the sea is warmer in winter ^^ and more salt in 1 Thin leaves or fihns of metal have little affinity for water, and have, generally, bubbles of air attached to them ; so that, when placed upon the water, the fluid is prevented from adhering to them, and thus they remain on the surface. 2 Depending not upon their absolute, but their specific gravity. 3 Being partly supported by the water. "* The stone may have floated in consequence of its bemg fiill of pores : these are more quickly filled with water when it is broken into small pieces. It was probably of the nature of pumice or some other volcanic product. 5 This is well knoTVTi to depend u])on the commencement of the de- composition of some part of the viscera, by which there is an evolution of gaseous matter. ^ Tliis is an erroneous statement ; it is not easy to ascertain what was the som*ce of the error. ' Rain, as it falls from the clouds, is nearly pure ; and rivers, or recep- tacles of any kind, that are supphed by it, are considerably more free from saline impregnations than the generality of springs. 8 This statement is altogether incorrect. 9 When salt water fi-eezes, it is disengaged from the saline matter which it previously held in solution ; a greater degree of cold is therefore re- quired to overcome the attraction of the water for the salt, and to fonn the ice, than when pvu'C water is congealed. 10 " Celerius accendi." We can scarcely suppose that by this term our author intended to express the actual burning or mflammg of the water, which is its literal and ordinary meaning. This, however, woidd appear to be the o]:)inion of Hardoiun and Alexandre ; Lemafre, i. 419. Holland translates it, "made hot and set a-seething," i. 46 ; Poinsuiet, " s'echaufto le plus vite," i. 313 ; and Ajasson, " plus prompte h s'ecliauffer," ii. 217. 11 The temperature of the ocean, in Consequence of its great mass and the easy diil'usion and mixtiu'e of its various parts, may be conceived to