In the Alps, Tyndall tells us, when the liquefaction is copious and the cold intense, icicles grow to an enormous size. Over the edges (mostly the southern edges) of the chasms hangs a coping of snow, and from this depend, like stalactites, rows of transparent icicles, ten, twenty, thirty feet long, constituting one of the most beautiful features of the higher crevasses. An icicle would be incomprehensible if we did not know that the solar beams may pass through the air, and still leave it at an icy temperature. One of the contradictions of ice is, that, formed at a temperature of twenty-five to thirty degrees Fahrenheit, it is as different from that which is formed when the temperature has ranged for some time between ten degrees and one degree, as chalk is from granite. The ice at the lower temperature is dense and hard as flint. It strikes fire at the prick of a skate. In St. Petersburg, in 1740, when masses of it were turned and bored for cannon, though but four inches thick, they were loaded with iron cannon-balls and a charge of a quarter of a pound of powder, and fired without explosion. The warm-blooded, fur-covered cat is just as contradictory--in one peculiarity at least. Gilbert White says, "There is a propensity belonging to common house-cats that is very remarkable; that is, their violent fondness for fish, which appears to be their most favorite food: and yet nature in this instance seems to have planted in them an appetite that, unassisted, they know not how to gratify; for of all quadrupeds cats are the least disposed toward water; and will not, when they can avoid it, deign to wet a foot, much less to plunge into that element." And there is quite as curious a fact pertaining to the rat. Naturalists say that his propensity to gnaw must not be attributed altogether to a reckless determination to overcome impediments. The never-ceasing action of his teeth is not a pastime, but a necessity of his existence. The ceaseless working of his incisors against some hard substance is necessary to keep them down, and if he did not gnaw for his subsistence he would be compelled to gnaw to prevent his jaw being gradually locked by their rapid development. And there is the tortoise. The same delightful naturalist we have quoted had a pet one, of whose habits he made many curious notes. He says no part of its behavior ever struck him more than the extreme timidity it always expressed with regard to rain; for though it had a shell that would secure it against the wheel of a loaded cart, yet did it discover as much solicitude about rain as a lady dressed in all her best attire, shuffling away on the first sprinklings, and running its head up in a corner.