ts
friction. Upon two platforms, _b_, at the extremities of the machine,
are fixed the water reservoir, C, and the receptacles, C', containing
fine sand or dry pulverized grit stone. As may be seen from Figs. 5
and 6, the bottom of the sand box, C', is conical and terminates in a
hopper, T, beneath which is adjusted a slide valve, _t_, connected
with a screw that carries a pulley, T'. By means of this valve, the
bottom of the hopper may be opened or closed in such a way as to
regulate the flow of the sand at will by acting upon the pulley, T',
through a chain, _t'_, passing over the guide pulley, _t squared_. A rubber
tube, _u_, which starts from the hopper, runs into a metal pipe, U,
that descends to the guide, H, with which it is connected by a collar.
Under the latter, this pipe terminates in a sphere containing a small
aperture to allow the sand to escape upon an inclined board provided
with a flange. At the same time, through the rubber tube, _c_, coming
from the reservoir, C, a stream of water is directed upon the board in
order to wet the sand.

As the apparatus with but a single endless saw makes but two kerfs at
once, Mr. Auguste has devised an arrangement by means of which several
blades may be used, and the work thus be expedited.

Without changing the general arrangements, he replaces the pulleys, P
and P', by two half drums, V and V' (Figs. 8, 9, and 10), which are
each cast in a piece with the crosspieces, D squared and D cubed, designed to
replace D and D', and, like them, sliding up and down the columns, A,
of the frame. Motion is transmitted to all the saw blades by a cog
wheel, X, keyed to the vertical shaft, _f_, and gearing with small
pinions, _x_, which are equally distant all around, and which
themselves gear with similar pinions forming the radii of a succession
of circles concentric with the first. All these pinions are mounted
upon axles traversing bronze bearings within the drum, which, to this
effect, is provided with slots. The axles of the pinions are prolonged
in order to receive rollers, _x'_, surrounded with rubber so as to
facilitate, through friction, the motion of all the blades running
between them.

The other drum, V', is arranged in the same way, except that it is not
cast in a piece with the carriage, D cubed, but is so adjusted to it that
a tension may be exerted upon the blades by means of the screw, _d_,
and its hand wheel.

Through this combination, all the blades are carr