Raftsman's journal. [volume] (Clearfield, Pa.) 1854-1948, 1858-09-01

winch were taken with this branch of the IN
yestigation, it will suffice to say that sirty-t,ro
| different kind Of rope were subjected to close
experiment before the exact form and charac-
ter of the cable to be employed were deter
mined. The cable finally adopted is thus de-
| scribed:
ssThe central conducting wire is a strand
made up of seven wires of the pUrest copper,
of the guage known in the trade as No. %
The strand itself is about the sixteenth of an
inch in diameter, and is formed of one straight
ly drawn wire, with six others twisted round
it, this is accomplished by the central wire be-
ing dragged from drum, through hole in a
horizontal table, while the table itself revolves
rapidly under the impulse of steam, carrying
near its circumference six reels or drums, each
armed with copper wire. Every drum revoves
upon its own horizontal axis, and SO delivers
its wires as it turns. This twisted form of con-
ducting wire was first adopted for the rope
laid across the ST. Lawrence in 1856, and was
employed with view to the reduction to the
lowest possible amount of the chance of con-
tinuity being destroyed in the circuit. 1t is
improbable in the highest degree that frac-
ture could be accidentally produced at precise
ly the same spot in more than one of the wires
of this twisted strand. All the seven wires
might be broken at different parts of the strand
even some hundreds of times, and yet its ca
pacity for the transmission of the electric cur
rent not be destroyed reduced in any incon-
nation of these wires is assayed from time to
time during the manufacture. to insure abso-
Lutte homogenity and purity. The strand itself
when subjected to strain, will stretch twenty
per cent. of IFS length without giving way,
and, indeed, without having its electricity con-
Quoting power much modified or impaired
Such is brief review of the agencies
which have been Immediately brought into
combination for the purpose of efecting this
mighty undertaking. In the gradual process
sion of the causes and means by which it has
marched to a triumphant accomplishment, art
and skill have only advanced side by side
with the slowly elaborated results of science
in pluckinS from the very heart of Nature the
secret OF her laws and movements And hence
in awarding our just need OF praise to the in
telligent faith which planned and the untiring
perseverance which, appalled, by no disasters,
has brought this great work to its desired con-
summation, let us not forget our obligations
10 the equally patient. if less conspicuous, Ia
bors of the philosophical student poring in
his cabinet over the mysteries of nature until
he reads in characters of light the secret
cipher of her being. The world without know,
but little OF these anxious and laborious en-
deavors of the sdrant, striving to pass that Of
ten narrow but always most difficult isthmus
which parts the unknown from the known.
The honors and emoluments which society J.
wards to the successful iarentor are too often
but partially and grudgingly bestowed upon
the scientific discorerer, to whom the former is
indebted for a knowledge of the principles
which he has reduced into mechanical proper
tionS and made subservient to human uses.
If we are indebted to Morse for the electric
telegraph, it is because Franklin and Gal
vani, Volta and an Grsted, Faraday and a
Henry, have contributed by their profound in
vestigations to discovery of the hidden prin-
ciples which underlie the structure of that
wonderful work of mechanical art. In the
| pantheon of this latter-day glory there is room
for all-for the man of high thought pursuing
the acquisition of knowledge for its own sake,
and finding in the discovery of truth its own
exceeding great reward, as also for the man OF
practical achievement who reduces that knowl-
| edge to the utilitarIan ends of our daily life.
Let US apportion our honors to the latter as
not TO forget the measure of our obligations
to the former