New-York tribune., 1901-01-20


Iupin $. II is a safe inference that il has high
opinion of the serviceablity Of the idea That
corporation is certainly in a position judge OF
Sne value of the property which il has acquired. 4
and those who have followed the Columbia pro- |
tessors researches for the last few years have |
al along been confident that if he should attain /
the practical results which he sought he would
wonderfully extend the possibilities OF telephony
The problems OF long distance telephony and
iong distance telegraphy are different in several
particulars. by putting in two or three re
peaters" and fresh batteries between New York |
and San Francesca, it is possible TO telegraph |
from one city TO the otheg without difficulty. /
But no successful repeater or relay has been in
vented for the telephone. Scores Of experts have
sought TO devise such an instrument but thus |
Tar without success. The best that can be done
with existing land wires is TO talk from Boston
TO Omaha, barely half way across the continent
and less than two thousand miles. No doubt by |
materially increasing the size OF the copper wire
employed in this service the distance could be
somewhat extended. But the cost would be pro-
hibitive Already for long distance work a wire
is used that weighs s25 pounds TO the mile
whereas for local service 100 pounds will do. The
recent rise in the price OF copper makes the
situation even more embarrassing than IL was
three four years ago.
SUBMARINE TELEPHONY.
But the difficulty with submarine telephony is
even greater than with overland. 1t has been
practicable to work wire under the English
Channel, which is only about thirty miles wide,
and connect lines Herewith TO establish a
through route from London 10 Paris. But only
four years ago Mr.. Preece. at the head OF the
British telegraph and telephone service was
signing in vain for a submarine cable that
would work across the interval between Eng
land and Holland, los miles. He made rum
Der Of suggestions with that object in view.
These related mainly TO the form and arrange
ment Of the the copper conductors in the cable
and to the insulating material introduced into
the latter. But that line of experiment yielded
practically result.
Professor Pupin employs an altogether diff
feTent principle and one which makes il as
easy to talk through three thousand miles OF
ocean cable as between Dover and Calais. 1t is
a radical and immense Improvement in the art.
The remedy which he employs can best be un-
derstooa after an explanation Of the evil with
which he deals.
DIFFICULTIES TO BE OVERCOME
When steady current of electricity flows
through a wire a form Of resistance is developed
that corresponds TO the friction OF water in a
pipe. But if the current is frequently inter
rupted in telegraphy or telephony, other
phenomena arise. These occur in the insulating
medium Immediately surrounding the conductor
With land wire the dry air is the scene Of this
or gutta percLa. The conductor not only con-
reys a current from end the other, but
when the current starts il creates a sphere of
influence" just outside ITS surface along its fun
length. When the current stops, this envelope
OF energy is withdrawn. These operations in
Volye a certain amount of work and require
little time, and If the current resumes its flow
100 soon after cessation a blurring effect VIII
be produced. The appearance and disappear
ance Of the electricity at the terminus Viii not
be so sharply defined IL Was at the start
This trouble puts limit on the speed at which
telcgra,,hic messages can be sent by cable.
Thirty words a minute is the maximum and
twenty the ordinary rate As there are about
seven letters TO a word, and the operators
key is closed three times to a letter.
there are six hundred eight hundred waves
a minute or about ten twelve a second
Faster sending than this results in a chaotic
stumble Of signals. Now, the vibrations OF a
mans voice vary from about 10 to 100 a
SECOND and those Of a wOman's are much more
freauent PATHS highes' notes contain one
thousand or more sound waves TO the second
The vibration Of a business mans voice, there
fore is a dozen times more rapid than the
maximum manipulation Of cable operators
key.