The Portland daily press. [volume] (Portland, Me.) 1862-1921, 1865-08-25
THE MONT GEMS TUNNEL

+,,;s Accent enterprise, now in processof ac-
ooroDIisbmentb by the Italian Government. We
oonJense few facts for the benefit Of ourread-
or, who may tbe interested in the processes by
which railway tunnel is being driven through
that tremendous barrier which the Alps i'm
pose between Italy and the other nations OF
Europe. Repeated have been the efforts, nom
time to time. to devise means for surmountlng
this barrier, but thus far their success mas peeh
but partial. "The genius Of Napoleon did
much when under his auspices the SUMPTION
road was made, and the traveller could clmD
the lofty summit of the Alps comfortably seat
al in his carriage" This was followed by
similar roads across the St. Gothard, the Splu-
zen. and the Stelvio, and when these were
it seemed as if engineering skill had
lone its utmost to make highway into Italy.
Yet with the days of steam came feeling OF
discomfort at these old slow modes of travel.
The jolting diligence crawling slowly up and
down the mountain sides, was necessity not
patiently acquiesced in. The question would
occur, as it possible for locomotive to scale
chat lofty wall or, if moi, is it impossible to
carry a railway through the AlpsY' Some sue
cessiul experiments in the waa of Alpine tun-
nelling accomplished by the Austrian engi-
neers in constructing the road from Vienna to
Trieste, encouraged the idea that such an at
tempt might prove practicable. There were
discussions and plans year after year, but the
precarious condition of italian affairs, and the
anfavorable state Of Italian finances, prevent
ed any action in the matter uutil Count Ca
your became the head of the Government,
when his energetic mind revived the scheme
of the tunnel, and gave it practical develop
mant. "a concession was made to FRENCH
company Of line connecting the Mont Gents
with the railways of France by the valley Of
the Arc. In Piedmont the Italian govern
ment undertook the construction of a line as
lar as Susa on the other side of the mountain,
and for some time the idea was entertained Of
carrying train across the Alps and so connect
in the two lines Of railway. Independently,
however, of all other difficulties, there was one
which, in an economic point of view, render
sd'such a scheme Objectionable. To overcome
a given height a locomotive must expend as
much force as is required for travelling given
length; and ii was found, ON calculation, that
to climb to the top of the Mont Gents was
equivalent to adding more than ninety-two
miles to the length of the journey which the
train would have to perform" To drive a,
tunnel through the solid wall of rock from sew
en- and half to eight miles in thickness, was
the gigantic project finally resolved upon, and
sEhis, perhaps the most stupendous work of our
age, is now steadily advancing to completion.
The manner in which the work of boring is
carried on is by no means the least interesting
part of the subject. The engine by which this
Is done consists mainly of an iron bar which
Is darted out like the tongue of an adder
against the opposing rock, with wonderful We
locity. and force. To find a suitable motive
power for this engine was long desideratum.
Steam was of course out of the question, for
team can only be produced by fire, and fire is
The great deyourer of air, so that to introduce
it into the Alpine tunnel would have been lit
lie short of suicide. 1t was reserved for three
Iteiio,a- aAaA..-, AZ AZ ces.A--s;u2-, c->.4l:.
and Grattoni, acting in amicable concert, to
overcome this great difficulty The principle
of their invention is the compression of the
atmosphere by means of water, so as to reduce
its volume and thereby increase its elastic
pressure. If a body of ale is reduced TO 1-6 of
its ordinary bulk, it acquires an expansive
force equal to that Of six atmospheres, and
This has been found sufficient for all the pur-
a. 1F o.
above the mouth of the tunnel there is
mountain torrent which is never frozen in the
! coolest weather If canal were traced from
this it would convey mass of water with
moving force per second equal to 900 horse pow
err. But this was more than was required,
therefore a reservoir has been constructed at a
heigth of $50 feet, which gives moving force
Of 29S horse power. BY means of this force
another reservoir Is filled, and kept filed with
compressed air ready stored for use. This air
is passed through long pipes into the tunnel
where its made to drive the iron tongue of the
perforating machine. Thus the torrents of the
Alps and the free mountain air are the slave
by whose labor the heart of Alps is being
pierced % le.e a
. The arch of the tunnel is nearly semi-cir-
circle. 1t is twenty-five feet three and hah
inches wide at the base, twenty-six feet two
and three-qualter inches wide at the broadest
part, and twenty-four feet seven inches high.
IL is intended that the tunnel shall rise from
the north to the middle with an incline of one
in forty-ive and hall, and then drop imper-
csptibly towards the southern extremity with
an incline of one in 1000. The length already
finished is little more than two and hall
miles This leaves about five miles and eight
chains yet to be excavated, and at the rate OF
| progress which. the work is now making, It
ought, unless some unforeseen accident occur,
TO be completed in five years from the present
time. Then viii have been accomplished an
enterprise which, TO use the words of M.
Menabrea, in the Italian Chamber on the 4th
of March, 1858, twill be for the glory of Italy,
and the greatest benefit to all her population"
And not Italy alone. All Europe has an In
terest in the success of this artery through
which will flow the stream of traffic from Ger
many and France. "a few years ago the pass
of the Mont Gems glittered with the bayonels
and resounded with the tramp of a French ar
my marching to rescue fair Italy from the
grasp Of the foreigner. Now more peaceful
conquest is going on over the obstacles which
Nature has imposed, and the Alps themselves
ara yielding to the potent spell which science
and art together are able to evoke. 1t would
be difficult to exaggerate the importance of
the result; and if It is achieved, the Alpine
tunnel win be one of the blessings of hunani-
ty, and exist for ages an irnperishable monu-
1nent of patient energy and engineering Skill"
"SrANDIsH; A story of Our Day" is the title