The Sun.
London, England, 1861-08-01 00:00:00

TILE ITALIAN RAILWAY TUNNEL,

TURIN, July 27.—The projected railway tunnel
through the Alpine barrier between France and
Italy, that is, between Savoy and Piedmont, is
actually fast progressing towards its perfect reali-
sation, and the new method, the new motive
force employed here to piene a carriage way
through seven or eight miles thickness of the
mountain, has proved even more efficient than its
inventors had promised.
The excavating machinery, as designed by
Messrs. Grattone and Sommeiller, consists of a set
of chisels and steel pointed instruments propelled
against the solid rock by the elastic power of con-
densed air in a closed horizontal tube, when the
air has been suddenly compressed by a rush of
falling water poured dawn into a vertical tube,
at the other end of the horizontal. This econo-
mical substitute for steam, in a country where
there is no coal, but where torrents and cas-
cades are available at every turn, is now rapidly
opening a new high road for our travellers and
traffickers to pass from England via France and
Italy, to Egypt, India, and Australia. Instead of
having nearly to circumnavigate the Mediterranean
as they now do, from Marseilles all round outside
the islands of Sardinia and Sicily to Malta, and
thence to Alexandria, they will have an unbroken
land journey from Calais to one of the Adriatic
ports, almost within sight of Corfu, and there em-
bark in the Vectis or some other English mail
packet, shortening the voyage to Alexandria by
two-thirds of its present duration.
The Minister of Public Works, Commendatore
Peruzzi, accompanied by several members of the
Chamber of Deputies, and an Inspector-General of
French Engineers, devoted two nights and the in.
tervening Sunday, without absenting himself from
his usual week-day labours, to visit the Italian end
of the tunnel at Bardoneche. The French end of

it is at Modane, and they are cutting away at the
same time, with about equal speed, approaching the
dead waist and middle of their gigantic enemy, the
mountain, through whom they are boring such a
hole. In the presence of this company, and of
several distinguished Italian mechanicians, the
boring apparatus, within less than one hour, made
70 perforations, varying from 60 to 90 centimetres
in depth, in the vertical face of the schistose rocks.
The machine is then drawn back along the tunnel,
for a hundred yards or so; the holes, which may
be an inch or so in diameter, are charged with gun-
powder, and exploded like an ordinary mine.
With a single pointed drill, moved entirely by this
force of condensed air, a hole of sixty centimetres
in depth, or about two feet English, is bored in
ten minutes, which the manual labour of three
strong miners could not do in an hour. The ordi-
nary action of the machinery is to pierce twenty or
thirty holes simultaneously in a narrow space where
three or four men could not easily stand working
together. The time gained by applying this new
system may therefore be easily calculated. Some
time must of course be lost in withdrawing the
ap-
paratus, after boring a set of holes three or four
feet deep, then exploding them and removing the
rubbish, after which the set of borers may again be
advanced, and the air tubes adjusted for another
stroke. The whole series of operations does not,
however, require three or four hours, so that several
distinct steps forward are made in a day. For the
last few weeks, on the Modane side, they have been
getting on at tLe rate of six metres a day, which is
at the rate of more than two kilometres, or more
than a mile and a half in the year. It is reasonably
expected that as theworkmen grow more expert they
will do three kilometres a year, at which rate the
tunnel will be finished in 1864. The increasing length
of the horizontal air tube, as the boring proceeds, is
found not to diminish the motive force, although
where it stands at present the boring apparatus
works at a distance of 1,500 metres from the place
where, the water falls. Another unfavourable pre-
diction was, that they would come upon granite, or
tap subterranean lakes. The rock, however, is of a
very manageable consistence, being a rather soft
schist, with some veins of silex ; and very little
water oozes from the roof or sides of the tunnel.
The contracts that have actually been nego-
ciated, and which the Legislature has approved,
along with some other contracts still open to the
earth-subduing Titans of the modern world, on
terms which the Ministry has been authorised to
propose, extend from the northern to the southern-
most regions of Italy. From the Maritime Alps of
Piedmont and Liguria, which will be tunnelled
thefor
the line this morning decided upon, between
the system
port of Savona and the city of Turin,
already stipulated for and decreed reaches down to
. have been
those Neapolitan transverse lines which
conceded to M. Talabot and his partners,con-
neeting the Tyrrhene shore
con-
necting the Gulf of Salerno with Taranto
with
Bari
theni Adriatic,
and
on the opposite side. Below these lie the Calabrian
and Sicilian lines, incluidtehTdw iAondtashinieciihiiaaensst,dywLaehrngrnircehemi
isefonart
that Garibaldi madewe
all the railways of the
subject of dispute. The general design that pre-
vails throughout all these grand and useful under-
takings, since the revolutions of last year, is that of
Italian unity. They are intended to supply a con-
tinuous series of locomotive traffic roadways along
that inevitable direct channel of commerce between
Western Europe and Asia, from Mont Cenis, when