I have already mentioned the kiley, or boomerang, as a native weapon; but this most extraordinary implement deserves special attention. Its possession alone, I contend, redeems the Australian savage from his usually assigned place at the foot of the human ladder. Doubtless other nations--notably the Africans and Indians--have an instrument of somewhat similar form, but the main characteristic is wanting, namely, the return flight. Its usual form is a piece of hard wood with the curve of a parabola, about two feet long, two and a half inches broad, one third of an inch thick, and rounded at the extremities. One side is flat, the other rounded, and it is brought to a bluntish edge. It is discharged by the hand at one end, the curved edge being forward and the flat side upwards. After advancing some distance and ascending slowly in the air with a quick rotatory motion, it begins to retrograde, often falling on the ground behind the thrower.
As long as the boomerang retains the forward impetus and catches the air as it will naturally do--on the flat side, it continues to rise. When, however, the movement imparted to it ceases, it begins to fall, and its, course of falling will be in the line of least resistance, which is in the direction of the edge that lies obliquely towards the thrower. It will therefore fall back, in the same manner as a kite when the string is suddenly broken is seen to do, when it falls back for a short distance. But the kite, having received no rotation to cause it to continue in the same plane of descent, soon
falls, in a series of fan curves, to the ground, as also will the boomerang if it loses its rotatory motion.
Now it is evident that this apparently marvellous property of the boomerang (founded of course on a well-known law of projectiles) must be of great advantage to the natives, who largely use it for throwing among flocks of fowl on rivers, lakes, and marshes. When, after striking or missing its object in the water, instead of being lost it returns back to its owner.
There are several varieties of boomerang, but they all follow this law, being of course to some extent dependent on the skill of the person wielding it. Could any device be more ingenious.