Page:The Kinematics of Machinery.djvu/233

 PRIMITIVE LATHES. 211

workmen, as was probably the case also in the boring of large stone axes by the prehistoric men.

It requires here to be pointed out that the making of a cylindric boring, i.e., a hollow cylinder, must have been immensely older than the reverse operation of making a solid circular cylinder. The hole could be bored with a very incomplete form of cutting tool, for it is easy to make the hollow body tolerably regular in shape whether its generator, the cutting edge of the tool, be regular or not. Almost any piece of flint could be used for boring

FIG. 163 T

n wood, bone, or horn, if it were only sharp and of such a shape that it could be gripped. 33 The turning of a body, on the other hand, requires that it shall be placed in some kind of machinal bearings, which shall render possible its rotation about a fixed geometric axis, before a chisel can be successfully applied to it. It seems to me probable that it was the potter's wheel which led the way to the lathe. It can be shown certainly that the operation of boring was older by ages than the use of the potter's wheel, and that this again long preceded the lathe.

Perhaps one of the oldest forms of the latter machine is the one still in use among the Kalmucks. It has, as the figure * above shows, a horizontal spindle of wood resting in bearings, and caused to rotate by an assistant of the turner, by means of the cord between the bearings, exactly like the fire-drill in Fig. 161. The object to be turned is fixed to the free end of the spindle. The turner simply spikes his machine to the ground, places the little


 * From Klemm's KulturirisscnscJiaft, i. p. 387.

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