The workingman's advocate. [volume] (Chicago [Ill.]) 1864-1877, 1871-02-04

an index hand, d, The movevneuts Of which
over graduated circle, serve to indicate
the atmospheric pressure. In proportion as
this pressure increases, the tube fattens in
corresponding quantity; its curvatare in-
creases, its two extremities approach nearer
together, and the index turns 10 one dIrec.
ton When the pressure dininisbes, this
series Of effects is produced in the opposite
direction, and the needle turns the contrary
way to what it did before. This barometer
has the advantage Of being Light, portable.
and not easily damaged or rendered unser-
Vlceable. Il is very sensitive and correct.
The Mont Gents Tunnel
The great engineering triumph which
renders memorable the closing days Of the
year 1870, the practical completion of the
Mont Gents tunnel, is timely reminder OF
the truth we are apt to forget-2that the
worlds labor and thought are not silenced
BY the Lhock of war and the clash of ar
mics. Millions may be engaged in con-
flct, but the people are hundreds of mil
lions, and the success Of this, the most re-
markable engineering enterprise ever IN.
dertsken, will lead to results far more i'm.
portant, as affecting the masses of the
people, now and hereafter, than all the
battles which have been fought in Europe
during the past half century.
The work Of piercing the Alps, and
opening an easier and safer means Of com
munication between France and Italy than
that afforded by NaPOeO0's perilous road
over the mountains, or the still more peril
GUS railway which follows its tortuous
course, is one Of the most difficult ever
undertaken, and has besn fourteen years in
progress. Its length, from Bardoneche,
where the ground was broken on the
Italian side, to FOuFnesu, on the French
side, is fourteen thousand yards, or nearly
eight miles. Strictly speaking, it does not
pierce Mont Cer is, but is bored through
Col de Frejus Grand WALTON and Col de
Il ltOue, three lower peaks IF the Sa 10Y
| A ps Under the circumstances it was
impossible to sink shafts, as 10 ordinary
tunnels, and it was doubted by many ac-
compllshed and experienced engineers whe-
Their the completion of the work would be
found possible on this account, since it was
thought that men could not be able to
breathe, much less to work, lour miles
under ground To Obviate this difficulty,
an ingenious machine was devised by NM.
GratOnue and SOmmelier, the eminent
French engineers engaged in the work,
which, operated by means of compressed
air, not only kept the drills constantly at
work, but supplied abundant ventilation to
rhe Il mel One Of these machines, OF
80 horse power was set in operation a;
each eud OF the bore. The atmospheric
compression was effected by means OF wa
Ger power, and for fourteen years these ma
chimes have steadily cut passage through
be heart OF the mountain. Each drill,
which bad stroke equal to $50 pounds
weight, made 200 revolutions per I'inute
10 common rock the average progress YES
uIne feet per day, but through the white
quartz, almost a. hard as diamond, which
constitutes the vertebI8 Of the mountain,
De average progress did not exceed six
'een inches daily. 1t is said that while
working through this quartz the worAmen
! needed no lights, as the interior of the tun-
nel was brilliantly illuminated BY the show
er OF sparks which followed each blow Of
the drills: As preparation for blasting
about ninety holes, each three feet 10
depth aud three inches in diameter, were
drilled and charged with powder. The
machine was then Withdrawn and the blast
fired, bringing down the surface Of the
rock to the depth of several feet, and leav-
ny vast piles Of debris TO be removed by
raj. SO hard was the rock in manl
places that the drills often neeueU 10 Ue re-
placed every few minutes. The tunnel,
when completed, will have a double track
throu. hout, anil its cost will reach total
Of $50, 600, 900 francs.
This magnificent material enterprise was
originally undertaken by the Italian gov
crnment, which for many years prosecuted
The work alone The French government
subsequently, lent tell,iug band, and moi
even the war has checked for a moment
the progress Of the work toward a success
| ful completion. But while we give full
credit to the energy and enterprise of the
| JNO udAiOus, uuuCl ouSPiSOS q PCS
sage has been opened through the barrl'
Of the A ps, it is proper to state that. With
out the use of pressed air for the double
purpose of driving the drills and ventIlat-
ing the bore, the successful completion OF
the work ~orld have been indetnitel y de-
layed, if not rendered wholly impossible
This new motive power, which ~ at once
effective and economical, promises to be-
G, me a valuable addition, not merely to
the appliances Of modern engineering sci
ence, but to the progress of all forms OF
productive and manufacturing industry
The new principle SO successfully applied
by MN. GTatOune and SomIDeller, and We
believe by the engineers engaged on the
HoOsac tunnel, can be made as useful IN
operating looms and spndies as in driving
drIls, AID it is proposed TO bring this mo
i've power iutO general use in several man
ufacturng cities 10 this state in a very III
geniOus manner. TIE trial will first be-
made ID Rochester, where, by means OF
water power, atmospheric air will be com.
pressed into reservoirs, whence it will b
conducted 10 pipes, like gas or water, t.
machine shops, factories, and other estab
lishments a distance from the reservoirs.
II this plan succeeds at Rochester, an a.
tempt IA to be made to uiize the water
power of Niagara for the compression o.