Weekly Trinity journal., 1871-11-11
WEAVERVIILE, CALIFORNIA SATURDAY, NOVEMBER II, 1871

boring the Mont Gents Tunnel was secured.
Another invention, however, was needed to util-
ize all these triumphs of human ingenuity. The
use of steam as a motive power was hopeless in
so confined a space the labor of human hands
was equally hopeless in point of time but with
wonderous sdaptation of means to ends the
falling waters of the Alpine valleys were i'm
prsoned to compress the air the air was con-
duct along vast tubes as the cutting advanced,
and after doing all the hard work for human
hands escapes from its imprisonment, and made
existence possible for the very men who made
this air a slave The machine employed by NJ
Sommeiller weighed about coo pounds and
bored a hole II inches in diameter and feet
in 20 minutes. Eleven of these machines were
placed on a movable support, and could be
worked at almost any angle. Three or four
large holes were bored in the center of the head
ing and round these other holes of the ordn-
ary size, in all 80 holes. The large holes were
only for the purpose of weakening the rock
The other holes were filed with explosive mate
rial, aud were fred in succession and in detach-
ments, beginning with those nearest the center,
ana working outward. The advanced heading
was the only place where these machines were
used the enlargement of the tunnel to the full
size, the building, ETC., were all performed by
manual labor The space thus excavated in the
rocky sides of the Alps was 26 feet inches wide
and 20 feet high fully admitting of four sepa-
rate lines of rails to traverse the tunnel. The
daily progress in the work, after some time,
showed a gratifying Improvement. From half
yard day, at first, the progress increased to
more than 10 feet per day. Each yard bored
cost not less than 81 900. The boring as de-
scribed was repeated, yard by yard, until the
entire eight miles was completed the work be-
coming more arduous as the tunnel increased in
length. Seventy yards of rock were displaced
for every yard advanced, and this had to be re-
moved to the mouth, while 25 cubic yards of
musonery had to be built in the same yard OF
tunnel, with materials brought on the average,
more than ten miles.
One-half of the tunnel was completed in nine
years Qs66), the third quarter by the end of
1868, and the whole mountain mass a thickness
Of IL, 1886 meters, or nearly eight miles, was
plefceu through from emu 10 emu Delore Chrlst-
mas day last year.
The construction Of the tunnel gave constant
employment to about 2 600 men, who were pro-
vided with dweling-houses along the banks of
the torrent of Rochemoes. When at work in
the tunnel the men relieved each other every
eight hours in the workshops they did on the
average ten hours work daily. All apprehensions
of mephitic air in the tunnel, if they ever had
any foundation, are by this time fully dispelled
A correspondent of Lyons journal, who re-
Gently went through the tunnel, says: "The
ventilation is excellent, and the current of air
perceptby felt the heat was so moderate that
an overcoat was MOTTO be disdained. All the
Swiss stories about heat intense enough to pro-
duce aspbyxia are pure inventions"