206
KINEMATICS OF MACHINERY.
ritual that the sacred fire should be lit 360 times, with nine different kinds of wood, upon each day of a whole month.
The discoveries made in recent excavations allow us to conclude with great certainty that primitive nations used some such arrange- ment as we have described for working those borers with which to our astonishment they were able to drill holes in wood, bone, horn, and even in very hard stone. The inhabitants of some portions of the world still use this twirling apparatus for boring. Indeed it has lately appeared that the deeply-bored stones, emeralds, rock crystal and nephrite, carved with figures of animals, which were discovered in South America by Humboldt and Bonpland, and looked upon by
FIG. 161.
them as belonging to some higher culture long destroyed, were fashioned by means of the simple twirling-stick of Fig. 160, or per- haps by that of Fig. 161. The secret was that sand and water were used along with the boring-piece. A single piece of carving re- quired years, perhaps more than one generation, for its completion. 25 This whole question is put in an entirely different light by the fact that the words now in use for boring were in no way originally connected with the making of a round hollow in, or hole through a piece of material with which we now think them inseparably connected. They all rather imply, more or less, the idea of
