Daily Richmond Whig. [volume] (Richmond, Va.) 1865-1869, 1865-06-21
RICHMOND WHIG.
RNING.JUNE 2l, 1865.
THE ATLANTIC TELEGRAPH.
COMPLETION OF THE CABLE-PRECAU.
TIONs AGAINST ACCIDENTS BRAKES,
ETC, ETC,
ndon Times, NAV %,


Yesterday the last mile of this great cable was
completed, and wound through the las. of the
covering machines, in the presence of large
number of distinguished visitors who had assem-
bled to do honor to the occasion. Beyond the
recording the fact Of its completion, very little
took place at the works Of the Telegraph Com.
pany yesterday to call for special remark. All
the most distinguished electricians and eng gineers,
and all the leading scientific gentlemen who
have 80 long watched and aided to the utmost Of
their power the promotion Of this great scheme,
were present together with all, or nearly all, the
directors Of the Telegraph Maintenance Com.
pany Mr.. Glass as usual, receiving the visitors.
As mere sight there was very little to be wit
nessed-much less, In fact, than might have been
seen at the works any day this twelve month
past. Only one machine had half mile
to complete-that Is TO say, TO case the core
with Mr.. Wrights most ingenious and sim.
pie patent of wire enclosed with strands of
hemp which form the outer covering. When all
the visitors were assembled this was started, and
the core wound regularly and slowly through the
centre OF the machine, which, revolving round at
great speed, completed the outer case of hemp
and iron. Working ut fourteen hours q day each
machine is able thus to cover four miles an hour
the average rate of manufacture for the four
day. As the cable is drawn out of the machine
it passes through guage, which congresses it
firmly, and then out OF the mandatory away to
the tanks, where 1t is coiled under water, and
every change in its electrical condition noted
with care and minuteness that have certainly
never been applied to any other cable. From
first to last indeed, IL has been subjected TO Sc
ries OF the most searching electrical tests, the
andard of insulation being fixed at resistance
per nautical mile equal 10 10000 900 of Sic.
Uen's units, at q temperature of 10 degrees-R
standard wholly unprecedented in any former
work Of the kind. In actual practice these tests,
great as they were, have been considerably
exceeded, and the present Atlantic cable
has come out successfully from q series OF
trials of the most crucial character. The results
which have been obtained have been due mainly
to the searching investigation into the qualities
OF insulating substances which is now practica.
BILE by means Of the beautiful mirror galvanome.
ter of Professor Thompson. Another of the tests
employed was soaking separately each joint Of
the gutta.percha covering for twenty.four hours
in warm water previous TO passing the electric
current through. third, and perhaps the most
trying and continuous test, was that of allowing
no part OF the cable to be out of the water, ex.
cept while merely in transitu from one reservoir
TO the other; and in connection with this II may
be mentioned that the wrapping of jute yarn,
which forms the padding, around which the ex-
tar, as in other cables, which has the effect OF
temporarily stopping up and conceang the mi
mute flaws has been simply tanned to preserve II
from decay thus admitting the water TO search
out every part of the cable, and keep it, In fact
constantly surrounded with wrapping of wet
yarn.
Towards five o'clock yesterday the last few
fathoms Of the great coil began to be drawn
into the machine, and In few minutes after the
end was wound up sei.acting bell rang TO give
notice that the machine was empty, and almost
at the same moment the end came down into the
tank, and the last coil OF the cable was slowed
away. lhe next great subject of interest was
the inspection of the paying-out apparatus,
which has been already fixed up, and, by means
of an endless band kept constantly running
This beautiful machine Is an improved and ex.
tended copy as far as general principle is con.
cerned, OF that uked on board the Agamemnon
during the first memorable attempts. Its i'm.
prOvements and notifications, however are very
great. Though stronger and much larger, il Is
very much lighter, being almost entirely OF
wrought iron. II has six leading wheels, round
before reaching the main wheel or drum,
from which il will be finally submerged
Each groove in these six wheels Is sur.
mounted by what is termed jockey pulley-that
is TO say, q solid wheel which keeps the rope
down in the groove and prevents it overriding or
getting out of place. The main drum is about
seven feet in diameter, and in paying.out will
have three coils of cable around it, with guild.
ing piece of wrought iron pressing on them side.
| ways TO keep them compactly together. AS the
friction on the guider is great and constant du
picate is provided In case of heating, which can
| be put in gear, with the rest Of the machinery
without the slightest stop on any part A second
| drum has also been fitted in case Of anything
gc ing wrong with the first. Each of these drums
faatn nI air nntNla
genious brakes, invented by Mr.. AppOld for the
first expedition. The ordinary condition of these
brakes Is TO maintain sufficient check upon
| the drum, 10 keep a strain of say 30 cwt. OF
40 cwt upon the rope going out, but it con.
| stsntly happens that suoden rise of the
ships stern from q wave gives the cable @
| strain that requires the instant removal of the
breaks to relieve it. This Is accomplished by 9
dynameter placed the cable after it leaves the
paying out machine and before ii passes over the
| wheel astern into the Atlantic. This dynametel
| is only a heavy wheel resting on the rope but
| fixed in an upright frame, which allows II "a
slide freely up and down, and on this frame are
marked the figures which show exactly the strain
| In pounds on the cable Thus, when the strain IL
low, the cable slackens, and the dynameter sinks
low with it, when, on the contrary, the strain is
great, the cable is drawn "taut," and on it the
dyn .meter rises to its full height When it sinks
too low, the cable is generally running away toe
fast, and the brakes have to be applied to check
It, when, on the contrary it rises rapidly, the
tension Ia dangerous and the brakes have TO be
almost opened TO relieve it. The sin plicty of the
arrangement for opening and shutting the brakes
is the most beautiful Of all. Oppohte the dy-
nameter is placed tiller.whee and the man in
charge of this never lets 1t go nor slackens
his attention for an instant but watches
the rise and fall of the dSnameter as
sailor at the wheel watches his compass. =
single movement OF this wheel to the right puts
this brakes on, turn to the LETT opens them. A
good and experienced brakesman will generally
contrive TO avoid either extreme Of a high or low
strain, though there few duties connected with
the laying of submarine cables which are more
anxious and more responsible while they last
than those connected with the management OF
the brakes. The whole machine yesterday
worked beautifully, and with so little friction
that when the brakes were removed weight Of
900 pounds was sufficient to draw the cable
through it.
In order 10 guard against any possible sources
of accident, every preparation has been made IN
case of the worst, and In the event of very bad
weather, for cutting the cable adrift nd buoying
it. For this purpose wire rope oil great
strength and no less than i've miles long, having
q distinctive mark at every one hundred iathoms,
will be taken in the Great Eastern. This,
of course, is only carried in case OF despe.
rate eventualities arising, and In the earn
est hope that not an inch of 1t will ever
be required. If, unfortunately, its services
should be wanted, the cable would be firmly
made fast to its extremity and so many hu ndred
fathoms OF the wire rope according to the depth
of water the cable was In measured out. To the
other end of the rope an immense buoy would be
attached and the whole then cut sdrift and left
10 itself till better weather. In the experimental
cruises which were undertaken before the start
ing of the last Atlantic expedition this attempt
at buOying the cable was often tried in the deep
water Of the Bay OF Biscay, but never with any
great success, and In very deep water 1t would
be most forlorn hop, indeed to try 1t at all.
After going all over the works yesterday, and
inspecting oil the apparatus, the visitors lett the
buildings shortly before six o'clock, and were en-.
tertained by the directors Of the Telegraph Com
pany at banquet at the ship at Greenwich,