The New York herald. [volume] (New York [N.Y.]) 1840-1920, 1869-07-15

avoided because It is uncertain at what depth
snes e onna a. time: s atno1 SSo0 Is
not certain at what depth the vessels employed in
the seal trade may sometimes choose . TO drop an
the track Of the ice hoes These dangers avoided
In the track chosen for the French cable Further,
the track from the southern edge OF the Grand Bank
to St. Pierre and thence to the place OF landing at
Duxbury, Is entirely free from any danger nom Ice,
neet OF fishing vessels. The cable upon Mine Bank.
and from the Grand Bank TO ST. Pierre, and thence
70 Of g Be-
The cable. q now laid, starts in very shallow
water from NinOu Bay, but III four or i've miles
deepens from seventeen to twenty fathoms and Then
gradually shelves from thirty to sixty-eight and
gradually deepening. IL continues till In line with
the westernmost part OF the Irish coast, where,
taxing aoaem a, scsn6nr ri the
depth increases from 200 to 500 and 900 fathoms.
and then IN short distance to l, 700 iathOms over
all the rest Of the to midocean the bottom s
mud, shells ana sand ana with uniform depth OF
about 1000 and 1900 fatholns. At these great
over such bottom the line ID taken IN an arc OF
large circle, the most soutnerly point OF the cable
ns 20 S@9 osS the soun
ern end Of the Newfoundland Bank II Is SUNK IN
about $50 to 200 fathoms, the water on the bank
itself varying from 1ifty to ninety fathoms Tnus IL
is completely sheltered from ice which, If the ice
bergs pass the bank at all, must clear the cabey
which lies under its lee by some hundred fathoms OF
more. From this point 1t Is taken up due north In
the channel between the Green Bank ana the ST.
Pierre Bank IN an almost unyarying depth or 500
fatnoms. From this point out the course IS over
very regular sh0al water, so to speak-being at no
part less than 100 fathoms and generally over loo
TO Its termination.
During the whole course OF the Great Eastern
messages have been continually passing from the
shore 10 the ship; and while the latter has only on
rare OCCASIONS owing to the trouble and danger OF
making the necessary shifting Of connections, re-
turned the compliment each roll or pitch OF the
huge vessel has been faithfully Indicated by the
delicate instrument at Brest THIS instrument Is
that now universally adopted In working all long
submarine llnes-the rejecting galvanometer. The
principle OF tins most delicate instrument was dis
covered few years since by German electrician,
named Weber. This instrument consists OF small
mirror with magnet laid across us back. and that
the TWO are very small indeed may be judged by
the fact that both together weigh less than three
eighths OF q grain. This enthusiastically small re-
nec4Or, which is intensely bright, Is suspended by
silk thread as fine a hair III the midst OF small
circular coil OF insulated copper wires Directly
current Is sent through this circular coll, no matter
how sight, 1t induces another electric within
its circle, which acts III an opposite direction, and
this causes the little magnet at the back OF the mir
ror TO turn to right or left and OF course, to turn
the little mirror with its rejecting ray light with
it. BY very simple arrangement this line ray or
light is thrown upon horizontal graduated scale.
about three feet long and three 1eet distant from
the mirror. Thus when current Is sent through
the little circular coil round the mirror the magnet
is acted upon, and turns the mirror with its ray OF
ght-say on the left OF the scale In front of it.
When the current reversed and that Is Instantly
done oy pressing Tue KEY "a me speaSng assru
sent In the opposite direction and this IN turn sends
the ray Of Sght from the mirror on 70 the opposite
side OF the scale 10 the right When the ray OF light
rests stationary any part OF the scale 1t means
dot; when 1t moves rapidly to the right or lett 1t
means many dashes, according to the distance it
goes. Thus the little pencil OF light makes dots or
dashes on the scale, just as the old Morse Instru'
ment used to make them in visible ink on paper,
and any combination OF words or letters or
figures can be formed and read with the utmost
SS tine avn ce.k tS s,,sr n nov
II sends. When the cable Is at rest the light re-
mains stationary In the centre OF the scale at
hAn favlff Ia ahntu
by the currenA Or the reverse currents turning the
light more to the right or left OF the centre OF the
that Is, when the cable has paredthe little ray Of
light files OF the scale altogether, ana Is never seen
delicate is this instrument that most distinct mes
sages nave been sent through the whole ieDgthof
the present French cable with no greater battery
power than that Afforded by adys thimble filled
with weak sulphuric acid and water. It was by this
refecting galvanometer that the watchers at
Brest knew whether the Great Eastern, at the
other end OF the long rope OF hemp and steel,
was steady or not. Each rOn OF the ship produced
slight magnetic current In her Vas: coils which,
transmitted through the cable the sensitive hsru
ment, turned the ray OF light TO the right or to the
lett OF the scale thus showing in a fraction OF
which the vessel was rolling This unceasing vibra
tion followed the voyage or the ship, marking its
progress aud incidents TO the close.
The task Is now completed with as full success.
over the most dangerous part OF the route Could
French Islands which is supposed to nave been
known to the Basque fishermen before the NortAmen
discovered yinland, will start our with wide
nOtoriety. 1t Is SO rocky as wholly to pre-
clude vegetation of the tenderer sort, but has
had an interest TO the French government because
large fishing fleets have for years been sent Que
there by the nducement OF liberal bounties. These
fleets employ as many as IL 900 men at ST. Pierre and
the Great and Little hlqueon Islands, which form
the group. The population subsist entirely by FISH,
ing The cod, herring and whale fisheries have
proved very productive, and France has had the
gacity to hold fast by ner little North American
nursery. 1t is added moreover, that for year past
France has been industriousiy accommodating military
stores at st. Pierre but for what purpose not def
ntely known.
The laying OF the final portion OF the cable to
Rouse's Hummock, in Duxbury, at the entrance OF
Plymouth Harbor, will be the work Of some days
longer. The main office will be III the old Bank
building at Duxbury from whence the connecting
wires to this City are rapidly going up,