“Not at all,” resumed Gilbert. “In some cases it is governed by certain laws; in others it seems to set the same laws at defiance, giving strange contradictions. Take water, for instance; most substances expand by heat and contract by cold, but in water there are strange anomalies, the scientific causes of which are mere hypotheses, though their utility is well known. Only to a certain degree is water contracted by cold, when a further increase of cold expands it instead of causing a greater contraction; thus water cooled will contract to 40° F., and if further cooled it expands till 32° F. is reached; it then becomes solid, or ice, when it again expands, frequently bursting the pipe or vessel in which it is contained.” “But that serves a good purpose in the physical economy, I suppose?” “Certainly; this departure from the general law of nature is wise and providential, for as the water cools below 40° F. it increases in buoyancy and rises, to float on the surface, and when ice forms below it soon comes to the surface, on which it rests, protecting the water under it from freezing and preserving the lives of fishes and insects, for it is obvious that if rivers and seas were frozen to the bottom all life in them would be destroyed. Many of the seas would become nothing less than a constantly changing and unchartable conglomeration of sunken rocks of ice, and would be altogether unnavigable, for all the bergs would sink where no sun could get at them to melt and reduce their bulk.” “Go on, Gilbert!” said Godfrey, encouragingly, as his friend paused. “I have nothing to do, and this is deeply interesting to me; besides, I have for some time been experimenting in freezing micro-organisms.” By no means loth to ride his pet hobby, Gilbert proceeded,—“An even more wonderful anomaly lies in the fact that if we take, say, a pound of hot water at, say, 100° and mix it with a pound of cold water at 0°, we get two pounds of water at 50°, the temperature of the hotter being reduced and the colder increased in equal ratio, but if one of them is ice, the temperature of the whole is that of the colder.” “I am afraid I don’t follow you there.”