Page:Popular Science Monthly Volume 29.djvu/146

136 outlines and other features, it is difficult to see how they escaped the cutting action of the sea-beach that must have been dragged over all of this surface as it was emerging from the sea. A single month of exposure to such waves as act even in the more sheltered bays would entirely destroy their more delicate outlines. After a careful examination of the evidence, Mr. Shaler has been driven to suppose that at the close of the glacial period the re-elevation of the land must have been accomplished with a very great suddenness.

The Genesis of Inventions.—In a paper read before the Anthropological Society of Washington, on "The Genesis of Inventions," Mr. Franklin A. Seely proposes the term Eunematics to designate the study of invention. He lays down, as fundamental postulates of this science, that, given any artificial implement or product, we must assume that there was a time when it did not exist; that before it existed there must have been a creature capable of producing it; and that such creature before producing it must have been conscious of needing it, or must have had use for it. Further, that every human invention has sprung from some prior invention or from some prior known expedient; that inventions always generate wants, and these wants generate other inventions; that the invention of tools and implements proceeds by specialization; and that no art makes progress alone. The last four of these propositions are verifiable from the history of any and of all modern inventions; the three former are deduced, and must be confirmed, if they need confirming, by the study of prehistoric inventions. In illustration of their force, Mr. Seely produces a theoretical study of the invention of the stone hatchet, a tool which represents the earliest human workmanship of which any knowledge has come to us, and presents in its rudest form the evidences of being the fruit of long-antecedent growth. When men used wooden poles for pikes, they found that their weapons were better if they were pointed. One man found that he could point pikes by rubbing them back and forth on a certain gritty stone he had. Other men brought their pikes to him to be sharpened. Then they found that they could sharpen them themselves on other stones. The sharp edge of a cliff was found to be particularly good for this purpose, and, when it was rubbed dull, another cliff-edge was looked out. Then, by some accident, the dulled cliff-edge was broken off, and a new edge, possibly even sharper than the old natural edge, was presented. The step was not long from this discovery to designedly breaking off cliff edges. Then some one discovered that the broken piece, fixed so as to be steady, or held in the hands, would also cut. When the stick-sharpener found that he could hold the stick firmly and trim it by passing over it the sharp stone held in the hand, he had a flint knife. Another series of experiments led to inserting the sharp stone into a handle, and another series to the differentiation of stones of different shapes and sizes for various purposes. Parallel with these processes were those of the development of cords for tying, from the first accidental shred of bark to fabricated strings of twisted bark or cut strips of hide.

Parental Peculiarities in Fishes and Frogs.—Fish and frogs arc not usually regarded as very careful parents, but a few species exercise something like a particular care for their young. Sticklebacks build nests for the reception of the eggs, and the males watch them and defend them against intruders. The males of sea-horses (Hippocampi) and pipe-fishes are provided with pouches in the under side of the body, reminding us of those of the opossum, in which the eggs are put after having been cast by the female, and are cared for till they are developed. These pouches seem also to be a kind of home for the young. The female of the genus Solenostoma also has a pouch, formed by the union of the ventral fins with the body, in which the eggs are laid and hatched, and this is furnished with a series of long, thread-like bodies bearing small projections, for the attachment of the eggs, and possibly for the nutrition of the young. The skin and tissues of the under-body of the mother Aspredo, when the egg-laying season comes round, assumes a soft, spongy texture, to which the eggs adhere till they are hatched, when the skin becomes smooth again. The