Lynchburg Virginian. [volume] (Lynchburg [Va.]) 1829-185?, 1851-12-18
~ We find, in the Richmond En-

qurer, description ola newly invented
tunnel drilling machine, which promises
most advantageous facilities in overcoming
the chief impcdiment to works Of internal
improvement.
"Some time since, (remarks the Enqui-
rer,) we briefly noticed new machine
that is to be brought into play, in excava-
ting the great tunnel through the Hoosack
mountain III Massachusetts. We were
Yesterday favored with the perusal of a
letter 10 Col. Crozct from the President
of the Troy and Greenfield Railroad, on
which the Hoosac tunnel Is 10 be found
and we have gathered few interesting
facts.
The machine, when finished, viii
weigh about 65 tons. 1t will be worked
by steam engine of rs horse power, and
win cost about $4,000. 1t will cut the
entire size of'Me tunnel for double track.
In other words, a circular hole of the d.
ameter of "a feet. 1t will probably enter
from six to fifteen linear feet per day
These data are taken from its actual cut
ting in granite. The rock in the Hoosac
Tunnels pure mica slate, highly stratiied
and the line of the tunnel enters the rock
at right angles with its qualification The
machine is called Wilson spatent stone-
dressing machine and has the capacity
of cutting pure quartz rock (silex or flint
with greatrapidity. Trap, such as found
in the Blue Ridge Tunnel, being hard
lgneous rock, may present greater OBJ
stacle to the machine. The machine is
described as truly wonderful invention.
The cutters are circularplates feast steel,
of II inches diameter, of an inch thick
and ground, with bevel on each side, TO
an edge. They are are placed on the
rock, at the angle of about as degree and
rolled over the surface with great rapid
ty. The edge is pressed into the rock
with great force and acts as a wedge, pry-
ing up and throwing off the rock in sur
prising manner. A block Of granite, ten
feet long aud four feet wide, was placed
on carriage, and submitted to single
cutter, guaeed to cut two inches from its
surface. II passed over the entire stone
in % minutes and cut off 1000 lbs. of
rock, leaving the same as smooth as any
hammer-dressed stone.
Its owner offers to prove that he can
make six revolutions per minute, on a
granite perpendicular face, and "a feet
in diameter. Each revolution will cut
one-eighth of an inch in depth-ihat is,six
eighths of an inch perminute, or 45 inches
per hour. In tunnel there must be
great difficulty in removing the debris,
which. of course, will greatly impede the
onward movement. The writer has no
doubt that our mechanics will soon cut
out our tunnels, without the use of gun
powder, none is required in this machine
nnd leave the walls as smoothas the rooms
of a house.
The writer adds thatthere has just been
invented in Massachusetts. a beautiful
stesm-drill, wonderfully simple, and yet
powerful beyond conception. 1t drills
horizontally into the hardest rock, eight
feet per hour. A number are ordered for
the Lake Superior Copper Mines, which
are composed trap rock. tied together
with strings Of copper-and earth knows
none harder. The owner is - Bige-
low, No. Z, Court Spare. Boston. 1t has
drilled flint without difficulty.
The Hoosac Tunnel is four miles long,
and it is proposed to sink it without shafts.
Hence unwearied pains have been taken,
and large sum has been offered, for the
invention of a machine which will cut ID
feet, on each face, per day. The writer
thinks it has been accomplished.