. Annual report of the Board of Regents of the Smithsonian Institution. Smithsonian Institution; Smithsonian Institution. Archives; Discoveries in science. 396 REPORT OP NATIONAL MUSEUM, Vancouver Island, employ it. The Indians of the Eio Negro, Amazon, and Orouoco Rivers in South America pierce the hardest stones with a twirling stick and sand. It is found also in Japan and Madagascar, giving it a range coextensive with the simple fire-drill. Fig. 51 shows the working of this drill in making fire. A shallow depression is first made near the edge of the hearth in order to give the spind
. Annual report of the Board of Regents of the Smithsonian Institution. Smithsonian Institution; Smithsonian Institution. Archives; Discoveries in science. 396 REPORT OP NATIONAL MUSEUM, Vancouver Island, employ it. The Indians of the Eio Negro, Amazon, and Orouoco Rivers in South America pierce the hardest stones with a twirling stick and sand. It is found also in Japan and Madagascar, giving it a range coextensive with the simple fire-drill. Fig. 51 shows the working of this drill in making fire. A shallow depression is first made near the edge of the hearth in order to give the spindle " ; From this depression a slot is cut down the side of the hearth as a duct for the wood debris which has been ground off. The operator then takes the spindle by its upper end between the palms of his hands and inserts the lower end in the shallow depression. In twirl- ing, a strong downward pressure is given to the spindle. The hands, which neces- sarily move down through the combined pressure and the back and forward mo- tion, must be returned quickly to the top of the spindle without allowing the air to get under the lower end of the latter. After continued friction, evidences of combustion are seen in the ground off wood meal. In shaping the lower end of the spindle, it is absolutely necessary that its point should be in con- tact with the bottom of the shallow depression, otherwise it will " bind " against the edges of the depression and defeat the object. The usual statement that a spark is ground out, igniting the dust, shows an error of observation. The heap of dust collected in the slot, which is an essential feature, smoulders until enough heat has been evolved to produce ignition by spontaneous combustion. Flame is never directly secured by this apparatus ; the coal must be placed in contact with tinder, or other ignitible substance and fanned into a blaze with great caution. Usually much smoke is generated in the operation. Great dexteri
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