Scientific American Supplement, No. 620 | Page 7

the drum, M, and the pulley, L, to the shaft, l, at the other extremity.
This latter is provided with a pinion, _l'_, which, through the wheel, F',
gives motion to the saw. The shaft, m, likewise controls the upward or
downward motion of the saw through the small drums, N and n, and the
two pairs of fast and loose pulleys, N' and _n'_. This shaft, too,

transmits motion (a very slow one) to the four screws, g and _g'_, in the
interior of the columns, and the nuts of which are affixed to the sliders,
D and D'. To this effect, the shaft, q, is provided at its extremities with
endless screws that gear with two wheels, _q_', with helicoidal teeth
fixed near the middle of two parallel axes, r, running above the table, B,
and terminating in bevel wheels, _r'_, that engage with similar wheels
fixed at the end of the screws, g and _g'_.
The car that carries the block to the saw consists of a strong frame, E,
mounted upon four wheels. This frame is provided with a pivot and a
circular track for the reception of the cast iron platform, E', which rests
thereon through the intermedium of rollers. Between the rails, e, and
parallel with them, are fixed two strong screws, _e'_, held by supports
that raise them to the bottom of the car frame, so that they can be
affixed thereto. When once the car is fastened in this way, the screws
are revolved by means of winches, and the block is thus made to
advance or recede a sufficient distance to make the lines marked on its
surface come exactly opposite the saw blade.
In sawing hard stones, it is necessary, as well known, to keep up a flow
of water and fine sand upon the blade in order to increase its 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, _t²_. 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, D² and D³, 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, D³, 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 carried along at once in
opposite directions and at the same speed.--_Publication Industrielle._
* * * * *

ROBURITE, THE NEW EXPLOSIVE.
A series of experiments of great interest and vital importance to colliery
owners and all those engaged in mining