The Hawaiian gazette. [volume] (Honolulu [Oahu, Hawaii]) 1865-1918, 1872-01-10

Ii may be as well 10 state that, though
called after Mont Gems. the tunnel really
pierces the Col de Frejus, and is situated
/ st least fifteen miles to the Southwest of
Mont Gents. 1t Is 500 feet above the
level of the sea, and $50 feet shove the
Mont Gems road at Modane. The aver
I age incline Is one in forty-tive TO 4 point
midway between the two entrances. The
exact length, according to very interest
ing account in the Journal des DeJatS, is
1 L, 2SS metres. 1t was calculated that the
distance would be 1920 metres, 50 that
the difference in the actual length is very
little. This wonderful tunnel of seven
and three-fifth miles. Is said to be four and
4 half miles longer than any railway tun-
mel ever made.
We now pass on 10 consider the ma
chimes BY which this work has been &C
complished. The same power-water-
tunneled the rock, and supplied the air to
the worklnen. The mountain streams of
the neighborhood, by hydraulic pressure,
compressed the air to six atmoSpheres,
and 50 worked the perforating machine.
The water was collected In a large reser-
voir higher than the mouth of the tunnel,
and a pressure obtained equal TO twenty
six feet perpendicular. Ten air compress
sing machines and two aerometers were
placed near the mouth of the tunnel The
eompressors were worked by the aerome-
tiers, which in their turn had yielded to
the water-pressure. The air having been
condensed in the eompressors, was forced
into the receivers to work the excavating
machine. The latter consisted of ten per
forators and seven jumpers. which latter
bore into the rock, being worked by the
compressed air instead of steam. These
made a series of holes about yard deep,
which, when the jumpers had penetrated
as far as they would 60, were filed with
gunpowder and exploded Before this
was done, however, the whole machine
and attendants retired to a safe distance
behind stout wooden doors. The debris
had then to be carried away. According
to the nature of the rock, about two or
three yards could be accomplished in
twentv-four hours. The machine excavat-
ed an arc of twelve feet BY eight; the
rest had to be doneby hand and We have
seen it stated that operations would have
been conducted quicker If gun-cotton had
been used instead of gunpowder, owing
to the smoke made by the explosion of the
latter.
Light was wanted, of course; so the
italian engineers manufactured their gas.
Throughout the work, these engineers
have shown themselves indefatigable; and
under their superintendent the whole
was carried out,-France, on the annexa-
ton of Savoy, agreeing to pay half the
cost. The whole amount has been stated
st 65,OOO, 900 francs, or 100000 but
from other statements 1 should think
Is. OOO. 900 nearer the mark. In conse-
quence of the rapidity with which the
work was executed, France has to pay
100000 of the Italians share; for at
first 1t was thought it would take twenty
five years, and France had to pay 5OO,O
francs for every year less than the twenty
FIVE, and 100000 francs for every year
les than fifteen. Imitators are springing
up. Already the St Gothard is to be
pierced and enterprising English engi-
neers even suggest atunnel from England
to France.
The old diligences took about nine hours
to cross the Alps by the Mont Cents route;
the Fell Railway did the same in four and
half hours, and now the official" train
went through the tunnel in thlSty-eigbt
minutes, and it is believed that when the
line Is in full operation, only twenty min
utes VIII be occupied
The vertical distance of perforated stra-
tum IS about 1000 metres. NJ. Ellie de
Beaumont read a paper before the French
/ Academy Of Sciences. Sept. 18th, to elicit