a sensible friction upon
the bushing through this shoulder and projection, and, in order to
diminish the same, the bushing is continuously moistened with a
solution of soap and water through the pipe, _g_, which runs from the
reservoir, G'.

The saw is kept from deviating from its course by movable guides
placed on the sliders, D and D'. These guides, H and H', each consist
of a cast iron box fixed by a nut to the extremity of the arms, _h_
and _h'_, and coupled by crosspieces, _j_ and _j'_, which keep them
apart and give the guides the necessary rigidity.

The shaft, _m_, mounted in pillow blocks fixed to the left extremity
of the frame, receives motion from the motor through the pulley, _p_,
at the side of which is mounted the loose pulley, _p_. This motion is
transmitted by 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 i