The Memphis appeal. [volume] (Memphis, Tenn.) 1886-1890, 1888-03-24
ELECTRIC WIRE PROBLEM.
INDUCTION. LEAKAGE AND OTHER
IMPORTANT FACTORS.
Various Methods OF Relief Applied In
England and Frsnoe-Distinct Differ
ences Between Under and Over
ground Systems.


10 remedy the telephone troubles after
nightiall, there has been perceptible i'm.
provement The council committee has
made no final report ON the subject, how
ever, and II Is not known what the result
will he. Whatever the. difficulty, II Is a
subject liable TO bob up at any moment In
future, and win therefore stand elabora-
ton, for the benefit Of the general public
An ArrEAL reporter had the pleasure OF
meeting gentleman yesterday who seems
to have been enuossed In study OF the
question involved, and from him obtained
interesting facts and views. In answer 10
leading question by the reporter, the
gentleman said;
"In a paper by Vim. II. Preece, read
before the British association, he says that
the difficulty in speaking Is chiefly due TO
the environments Of the wires employed.
When two or more telephone wires run side
by side, what issaid on one can be overheard
ON all the others and when telegraph
wire extends alongside telephone wires.
every current on the telegraph circuit Is
repeated on the telephone, leading 20
Kissing, frying, bubbling sound that Us not
only very irritating, but which On busy
lines entirely drown speech. When music
b. transmitted on one wire, II can bo heard
equally M well on all wires running paral-
Ill and contiguous This Is due 10 in
ducfion aud leakage"
"lnduciion seems 30 bc aparamount Inc
tor in the problem; what can YOU advance
~ an explanation oil that2"
Induction Ia term employed 10 dcsig-
nate the peculiar influence which elcctri-
fled and inagnetizcd bodies exert upon con-
Quoting and magnetic masses In their
nciehborhood. II two wires run side by
side for some distance every current Of
electricity sent upon one wire will produce
two currents IN the contiguous wire, the
one nj the commencement and the other
ai the emil OF the primary current OF cleo
tricily. The greater the intensity. aud the
mor sudden and abrupt the commence
incnt and ending Of the inducing current,
the greater effect u has on the induced
win. Those instruments, consequently,
which reverse their currents the most rap
idly aud suddenly, produce the greatest
disturbance. The powerful alternative In
tcrmittent currents used for certain electric
light systems arr death 10 telephones; they
cause an incceant roar that rcndeSspccch
IN impossibility There arc some appara-
tus in biography that require very power
inl currents 10 work them, which are
equally detrimental. Many attempts have
l'ecn made TO cure this evil, among which
ar
!. The scnriiivcncss u the receiver has
lccn reinccd 10 lc~on the influence of
The disturbing currents and the strength
of the telephone transmitting currents !
has been incncasel 20 ~ a. oycrpoNer The |
induced currents.
=. The influence 81 one wire ON the |
other has been screened OF by inserting
metal coverings in connection with the
earth between them.
q The suddcnncss OF the rise and fall Of
the inducing currents has bccn modified
Wv the insertion Of condenser, % electro
magnets.
4 Counicfbalandng OF ncnlullHing ef- |
icc,s have been ST up BY counter Undue.
ton apparatus.
Have thesc'plans met and conquered |
tlic diilicnliics ~ aniicipa,cdF'
"Noi much They and many others |
have lcrn proved either only partially sue /
t,7~iul or Wholly aborti,e The only |
ciI,T'iiyc mode of curing the evil at present /
"
metallic ciwuit 20 contrivcd that the two |
WINS arr IN very cl0sc proximity 10 each |
other, or thai they twist anpund each other |
~ ~ io maintain mean aIrmgc equality
al distance between themselves and tho
disturbing wire. When We have the two
wins of circuit Kept nj the same mean
distance rom the disturbing causes, how
ever near they may bc, the influence on
each must he scientifically the same. AMI a.
Tie one 10 u-cd Tor guing aud the other foe
returning. the similar influences must be
opposite in direction, and thcy mus, tbcrc.
f"re ncutn,llDc each other This plan,
which was originally devised ior under.
grmnd wires by Mr.. Brookcs, oi Philadcl.
plia. was found Ia be absolutely true In
practice. aud the English pofinfIicc having
laid down many hundreds Of miles on this
system with perfect success, invariably
constructs Ia circuits both underground or
eNcfgound In this way. II IL, Of cuur.e,
mofc expensive Than a single winc,
bat the great gain. the al,aolulc freedom
iium o,crhcaring, the privacy, and the
slscncc 81 cracking N well worth the extra
epei. Wires IN submarine cables are in.
variahly laid NJ with twist, ~ that no
special cuntrivanoc II nccJlcd on such
sirrr. aud la underground wins not laid
~ together a. cables, They are, % rule,
. clo-e 10 each other that twisting Il un.
,co~,ary; but ior oycnnuund purposes
twisting IL essential, and special arningc.
mcnts have 10 be- carried out Prof.
Hughes showed how this was 10 be done,
aud the MoNrr Mo-clcy carried itout piao.
lically In the ncighb0rhood Of Manchester,
England. There anc In the ncighburhood
OF Manchester about 400 mites oi under.
ground double wire twisted IN this way
working efficiently and thoroughly. Con.
N'uaiiuns have bpon carried ON over sew.
tnly uiib~ through wins that were erected
on poles carrying busily occupied tcle.
graphic currents, without disturbance OF
difficulty.
What figure dccs leakage Gu, In tho
The double vine system Il only also.
lutely effective ~ long ~ the insulation h
good. The moment Insulation fails con.
ncctiOn with the earth IL made, and then
We have disturbing causes due 10 currents
flowing through the ground, which are la.
erased va proportion 10 the deterioration
Of The insulation. Hence. good Insulation
D. essential 10 telephone working"
. what pari does the earth play ~ a 10.
fryoir ~ electricity p
The discovery u the telephone has en-.
hlilcd no 10 establish beyond doubt the
iacl that currents oi electricity actually
tmscn. the earhs crust The theory
that ilic earth acts a. great reservoir oI
electricity may be plmcd Ia the physicist