Page:Popular Science Monthly Volume 12.djvu/783

Rh thread or tail; the shot drops to the ground, but the fine woolly fibre is sucked into a large tube, and discharged into a chamber. This chamber is very large, and is covered with fine wire netting. The steam and air carry the woolly particles all over the chamber—the finest into recesses formed for the purpose, the heavier into the body of the chamber. . The wool is of a snowy white appearance.

The Mechanics of Nature.—The Rev. J. G. Wood, author of several popular works on zoölogy, has lately published a volume entitled "Nature's Teachings," which is intended to show that nearly every one of man's mechanical inventions has been anticipated by Nature. From a notice of the work in an English journal we copy a few instances of human inventions that have their prototypes in the animal world. Alluding to the principle on which the life-boat is formed, Mr. Wood observes that "the eggs of the gnat, which adhere together by a glutinous coating, are arranged side by side so as to form the figure of a boat; that the lines of the best life-boats are almost identical with those of the gnat-boat; and that both possess the power of righting themselves if capsized." Mr. Wood observes the principle of the screw in a fish's tail; finds a remarkable resemblance in the iron mast to the quill of the porcupine; and explains how the improvement in the construction of iron ships caused by making the outer shell double and dividing it into separate compartments is exemplified in the skull of the elephant. Many of the author's nautical illustrations are curious, and among others he points out that the Boy ton life dress is simply a modification of the Physalis, "which floats on the surface of the ocean like a bubble." The weapons used in war have also their prototypes in the works of Nature. In a chapter on projectile weapons Mr. Wood notices the archer-fish, which gains its livelihood by shooting drops of water at flies, and reminds us that the same principle was employed, though unsuccessfully, on the so-called pneumatic railway at Croydon. From the archer-fish we may pass appropriately to the anglerfish, a creature with an enormous mouth and small body. On the top of its head are some bones set like a ring and staple, and, at the end of these bones, long fleshy appendages, which, on being waved about, look as if they were alive. "The fish darts at the supposed morsel, and is at once in-gulfed in the huge jaws of the angler-fish, which, but for this remarkable apparatus, would be scarcely able to support existence, as it is but a sluggish swimmer, and yet needs a large supply of food." There are different modes of catching fish, and the capture by rod and line is curiously anticipated by the worm known to naturalists as Nemerles Borlasii, which can extend itself, some say, to ninety feet, and looks, as Kingsley has said, a mere knotted lump, small enough to be put in a dessert-spoon. The little fish that chances to touch this "slimy tape of living caoutchouc" has no chance of escape, for he is being "'played' with such a fishing-line as the skill of a Wilson or a Stoddart never could invent." The principle of the baited trap is illustrated by carnivorous plants like the Venus's flytrap of the Carolinas, and the Drosera or sundew of England, and the principle of the spring trap by the jaws of the dolphin. Defensive armor in its several varieties is strikingly illustrated by the protection afforded in many instances by Nature, and Mr. Wood's treatment of this branch of his subject will be found of great interest.

How Ants stand Heat and Cold.—The ability of ants to survive exposure to great cold or great heat, and submersion in water, is shown in a very interesting note by the Rev. H. C. McCook, published in the "Proceedings of the Academy of Natural Sciences" of Philadelphia. In one instance, a few ants, of the species Formica Pennsylvanica (the Pennsylvania carpenter-ant) dropped out of their nest and fell upon ice, in the depth of winter. Forty-eight hours later they were alive, being imbedded in the ice within the small depressions made by their animal heat. They moved about on being taken from the ice, and became quite active when placed in the closed hand. The power of resisting great heat is illustrated by Mr. McCook's own observations, as also by a quotation from manuscript notes on the "Ants of Texas," written by the late Dr. Lincecum. A community of that