Page:Popular Science Monthly Volume 32.djvu/295

Rh The object of his paper is to suggest a way in which this waste of resources may be in part remedied, and in which money may be most advantageously employed for the extension of astronomical knowledge. This way is through the establishment of a central agency to which funds might be sent, to be expended on observatory or other work, so as to attain the best results, independently of all local and personal conditions. No institution appears to be better adapted for such service than Harvard College. It is financially strong; the management of the funds intrusted to it has been excellent; and its officers know perfectly well what are the requirements of scientific work.

The Boomerang.—Several German observers have been studying the boomerang for the discovery of the secret of its curious course of flight. Dr. H. Landois, of Münster, from intercourse with a group of native Australians who were exhibited there, has found that there are larger and smaller boomerangs. The larger ones are slender crescents, about sixty centimetres long, five and a half centimetres wide, and one centimetre thick; plane on the lower side, convex on the upper side, pointed at either end, and sharpened toward the edges. The lower end is cross-grooved, to aid in holding it. The careful manner in which the savages manipulated the weapon, trying its shape, testing its qualities, and scraping it down, is significant of the importance they attach to its having exactly the right curvature. The wood of which the instrument is made is an extraordinarily heavy Australian iron-wood; and the only tools used in making it are sharp stones and pieces of glass. The smaller boomerangs are bent at an angle of 45°, but are in other respects conformed to the larger ones. An exhibition of boomerang throwing revealed a degree of strength in the natives which was in astonishing contrast with the thinness of their forms. They took the weapon in their right hand, with the flat side downward and the concave side forward, and with a run and a shout, threw it by a short jerk about one hundred yards up into the air. It flew away in a straight line, then turned to the left, and returned in a curved line back to the thrower, whirling around constantly and whizzing unpleasantly. The curve which the weapon describes in its return is not a screw line or a spiral, but is more like a figure 8. The savages seemed able to control their instrument, even when wind interfered to complicate its course. Once the projectile went astray, and, coming in contact with a gentleman's hat, cut it off as cleanly as a razor would have done. Herr Hermann Froebel, of Weimar, who seems to be a manufacturer of toy-boomerangs, as he speaks of having made eleven thousand specimens of the article, believes he has discovered the mystery of its shape. It is not a crescent or even curvature, but must have a kind of nick or sharper curvature in the middle, with the two arms of unequal length, in the proportion of about four to five. The arms should not be of the same thickness, but the longer one should be pared down so as exactly to balance the shorter one. The correctness of these principles may be verified by adding a very little to the weight of either arm, or by slightly shortening the longer one. The instrument will then no longer answer its peculiar purpose any better than if it were only a common stick. The peculiarity of the motion of the boomerang is due to the difference in the length of the arms, by the operation of which a divergence from the circular is imparted to its curve of rotation. The remarkable feature of the whole matter is that such savages as the Australians should have been able to discover the peculiar properties of this form and apply them. The fact shows what extraordinary powers of observation the people of nature possess. The attempts to give a philosophical explanation of the trajectory of the boomerang variously compare it with the caroming of a billiard-ball, the sailing of a piece of paper or card-board in the air, and the flight of birds.

What is Graphite?—Graphite is not lead, as its names plumbago and "blacklead" would seem to indicate, nor is it a carburet of iron, as some works of scientific pretension still call it. Except that some impure specimens contain about as much iron as ordinary clay, it is the purest form of carbon, the diamond not excepted. Professor W. Mattieu Williams believes that it is nothing else than extremely finely divided