60 On the Electric Telegraph of Prof. Morse. 
A description of the out-door arrangements of the telegraph 
would seem superfluous—but a few particulars may possess some 
interest. The use of poles for the support of the wire is in ths 
country universal. These poles vary in size with the resources 
of the company—the standard being thirty feet in height, buried j 
five feet in the earth, and having a diameter of six inches at least 
at the smaller extremity. The copper wire that has been hereto- 
fore used, weighing from 80 to 100 pounds per mile, is now uni- 
versally displaced by iron wire of a weight of 300 to 330 pounds 
per mile. This is single or twisted, unprotected or galvanized. 
The advantages of the protecting coat are counterbalauced by 
loss of pliability and toughness ; and good iron having withst 
the test for years, the ae wire is generally preferred. Its cost 
is te 6 to 10 cents u oS 
mong the elements of simplicity that e character and pre 
ticability to the American pete he. is the u , 
rn conductor. In the imperfect state oa our original weed | 
tures, the invention would tints been almost unavailable but for 
this facility, as it has been found very difficult to keep two wires 
separated through any great distance, for any length of time. | 
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The use of the ground renders only one insulated wire necessary. 
The ground thus used proves moreover, a better conductor than 
Wire ; it requires less battery to produce equal magnetic effects, 
and when the choice of conductors is given, the current seems to 
prefer the heterogeneous to the homogeneous circuit. Commu- 
nication with the ground is very easily established. A gas pipe 
in cities—a metallic plate buried in the ground or immersed in a 
well or river accomplishes this end. A few feet of wire thrown 
into a stream of water will establish the connection. If a wire, 
as fine as a hair, leading from the conducting wire as it crossed a 
river, were immersed in the stream, the interruption to commu- q 
nication would be as effectual as if the conductors were broken, o 
the current from either battery would be returned. 
In the economy of the telegraph, there is no more important 
requisite than careful insulation. A solution of the perplexities 
and difficulties that have opposed the successful working of lines, 
will shew the importance of insulation to be absolute. 'T'o attain 
it, several methods have been tried, generally varying in excel- 
lence with the expense. Experime nts on various lines have 
proved the best available non-conductors to be imperfect. 
With a view of protecting as much as possible the fragile insu- 
lator, the wire is supported from it in various ways. It has been 
usually belayed to glass “caps” shaped like those in fig. 4, 
pore es: the wire from their side (1) or sus staining it — 
groove. ‘These caps fit over wooden or iron pins. — 
peo st two blocks of glass are dovetailed to each seers 
such a manner as to allow a central opening for the wire. In 
Pen ene By sea 
