about to be thrown. In many even very good weapons the twist is scarcely perceptible, particularly if the blade be very thin. When the blade is exceedingly thin, the very slightest difference of form at the ends is sufficient to cause a reciprocating motion when the instrument is projected into the air. The twist in the ordinary right-hand boomerang is of the kind shown in Fig. 103. It is to be noted, however, that when the weapon is much bent in the middle, thus (Fig. 104), it is not necessary to give this twist to the ends of the blade. If a boomerang showing such a line as that in Fig. 104 were much twisted, the balance would be destroyed, and it would not return to the thrower.
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| FIG. 103. | FIG. 104. |
- 3rd. The section through the middle; two examples of which, full size, are shown in Figs. 105 and 106.
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| FIG. 105. | FIG. 106. |
As regards the length of the weapon and the curve, looking at the flat side of the blade, it is apparent, judging from the variations in the length and form, that the artist has a free choice within certain limits; but if he make a heavy weapon, the twist must be considerable, and the section through the middle must exhibit a bulge on one side, and a very flat surface, if not actually a depression, on the other.
The twist is clearly observable in all the weapons made by the natives of Victoria. It is exactly that which would be seen if one held each end of a thin strip of cardboard between the finger and thumb of each hand. If the upper end were held by the finger and thumb of the left hand and drawn slightly towards the left, and if the lower end held by the finger and thumb of the other were drawn slightly towards the right, the twist of the right-hand Wonguim would be accurately represented. This twist is the twist of the screw, and the property the boomerang has of ascending is due to its having this form.
The form of the weapon in section is apparently essential to its flight and return. It is observable in all the specimens I have examined, and in all, whether right-hand or left-hand, the flat side in gyration is towards the earth.
One can easily imagine the perplexity of an enquirer who should have a number of these instruments presented to him, some left-hand, some right-hand, and some apparently of the like form, but not made to return. His experiments with them would but embarrass him the more; and if he succeeded in throwing one weapon successfully again and again, he might conclude that his want of success with the others was due solely to their imperfections. With such help and instruction as the natives have given me, I would not myself venture to decide at once as regards some weapons
