The weekly pioneer and Democrat. [volume] (Saint Paul, Minn. Territory) 1855-1865, 1865-06-23
THE ATLANTIC CABLE.
Preparations on Board the Great
Eastern--Scientifc Tests.

The London Telegraph of May 23 has the fol.
lowing interesting account of the preparations
on board the Great Eastern for laying the ocean
telegraph cable:
DIFFERENCES BETWEEN 1858 AND 1866.
A visit was paid to the Great Eastern few
days since by large party of the directors
friends, and it may be said that all who under
stood the preparations which they saw came
away with greatly strengthened confidence
in the future of the new cable. Since 1858,
when the first Atlantic line was laid, the ad.
vance that has been made by the scientific
world towards cOmprehending electrical phe-
nomena is very great. It has been said by a
man well qualified to speak on the subject, that
electric science has passed, since that time,
from its childhood to its maturity. So far as
the phenomena connected with long electric
circuits were concerned, we had in 1883 no
knowledge whatever. The instruments in
common use were unsuited to receiving signals
through great length of cable the necessity
of providing for the conductor an insulation SO
perfect as to approach an absolute condition
was inadequately appreciated.
The best preliminary test for long cable
had not been devised, and the old Atlantic tele-
graph was laid without having been subjected
to any searching test on shore. Everybody
had advice to give concerning the management
of the wire, but no one recommended the pre-
cautions which subsequent experience has
shown to be necessary. When the signals be-
gan to fail the battery power was augmented,
and electromagnetic induction coils, which
rapidly helped on the destruction of the con-
ductor, were pat in circuit. No one thought
of nursing" the eable-of humoring its feeble
attempts at articulate utterance, and of finding
out what it said rather by listening acutely than
by constantly calling on it, in the language of
fba UiafOrio oo1Io fn Small Tho old
cable, however, is dead and gone part of it
has been picked up and applied to ignoble uses,
as race.hOrse past his work may be put into
the shafts of a'Hansom: part of it has been
abandoned, and lies where it may rest till the
end of time, in the clark unfathomed caves
of the deep sea. Let Us turn to the practical
present
SCENES on BOARD THE GREAT EASTERN.
The Great Eastern looks just now more like
an engineerss workshop than seagOing ship.
The vast eXpanse of her deck are covered with
wooden sheds and piles of timber. There are
smiths FORCES below, and between the decks
you might fancy yourself in machinist's fac
tory. The great engines of the ship, it is true,
have lost the bright look of machinery which
is in constant use; and the huge dull masses
of iron seem asleep, or in trance. Ii you
descend the ladders which lead to the boilers
and furnaces-an expedition which is more
like going down mine than any other TO which
| it can be compared-you find yourself in
| the midst of darkness solitude and cold !;
| but in those regions of the vessel where the
| cable is being shipped and watched there is
| every sign of keen, vigilant intelligence. When
| you understand what is being done, you see
| something more than this-that scientific fore
| sight of the highest order directs every step
and that the thick tarry rope, coarse and rough
| to appearance, which lies coiled away under
water in the tanks OF the ships manufactured,
| scanned and tested with as much care as the
| incest optical instrument in an astronomers
observatory or the most delicate apparatus
of fragile glass ever applied to careful expert
ments of chemistry.
THE sCIsN1IFIc TESTS.
1t seems impossible that there can be any fault in
the Atlantic cable when the Great Eastern goes to
sea To cay notbiog of t. tests app led to it a the
mandatory, it is tested not alo; after it has been
taken board but during its delivery into the ship
AS soon as length is BIO ght alongside one END d. is
other end with the instruments In the testing room.
The circuit is thus made through The whole extent
of the coil, the portion OF board and the portion
alongside. The process OF hauling In thea COM
mences and lheInsulatiol Is continuously observed.
The instruments In the testing room record the
smallest deviation ON a5sOl tely perfect insulation.
It will be understood that insu lion which shall
be quite Ierfect as an electrician understands the
word, is not tain able piece of metal separated
by means of the purest glass. and enclosed in the
driest atm sphere that can be obtained, will, if
time In speaking of insulation we must, therefore,
be understood to mean an approximate condition /;
but the approximation in the case of the new ATTAIN
tic cable comes near to perfection that this rough
| t Try rope is scientific wonder.
The last diving lsa ion the cid Atlantic cable
was forced through it by means OF galvanic bat
terry consisting of wo hundred and forty cells. The
submarine telegraph from London 10 Amsterdam is
habualiy W RI ed W til a ba terry Of fifty cells end
such battery is commonly used for the other sub-
mar ne lines of Europe. Signals have bean repeat
| of the cable now On board the Great Eastern by
means of one cell. Gavanic currents 40 feeble lat
they could thave been fe by the hand, and mlght
| have been pas ed harmessly through crcuit COM
pleted ny the operators tongue can be used to cor
| vey messages along length of cable hat would
We ,rlg stretch from lOndsn to st. Pee. burg.
Over needle instruments, such as tn Sc in ord nary
| use for land telegraphy, cur ent from oLe cell
| would be power ess.
To record such faint pusaions of electricity it is
necessary to use PROBES or Thomp on's mirror gal
vanometer. This beautiful ms rument cors SITS OF
mirror about he size of fourpe my piece, mad Of
micro cope g'a e, and go thin THU l. weighs On
| grain On the back of this mirror minCte nj g.
net is fIed, AID thu supp emented it is suspended
| By silzen ibr, in the heart o. a COL OF wire SO
that any cur ent passing trough the coil fleet;
tn ma net and the mirror along with it. a ray Of
lig' Il. cted by the rr falls on tcae oil tan'
taintsst movements. Tfferant combinations o.
these movements represent the differeEt letters o.
the alphabet, and thus the appsrently cratic wan
ueIlLSS CT ray OF ugnt are maze 10 convey me 1
| ser ce An in: trumeIt o. this kind Is constantly
used to test the able as it is haule1 board ant
if any fault had existed it could not have passed
without election. Up to this time, when there are
on board the ship and alongside 1870 miles of cab
| no fault has been discovered.
| THE IMMERSION.
The ma hnery for paying cut is not yet on board
| but Is being put 10 yelh at the Greenwich worEs
| The process of immersion will take about a fort
| night The begi ming of the .hore end will be laic
by email vessel, VIII CHI will meet the Crest Eas err
about twenty miles from the Irish coast. The cable
will then be passed board, connected with that In
the great tanks, and the big ship will begin her voy
age. To the nit lated this process of cutting AID
joining the cable appears very mysterious, bnt the
engineers who are used to the wo,k face it without
any hesitation. The joints do net really eneangel
either the insulation the strength OF the cable a
wherever they are m de the external and conduct ne
wires are spl.ced along considerable length-s6m
ii es not less than thirty yards AID the gutta per
cha carefully put On in separate layers firmly pressee
| together by mea, of warm irons. The complete
ness of the joint is tested by wing 1t p an nsuated
metallic vesse, contsining water and ascsrtaining
by of tests applied to this vessel whether any
electricity escapes fran the joint as current Ii
passed along the cable