Evening star. [volume] (Washington, D.C.) 1854-1972, 1903-04-16
TELEPHONE GROWTH
MORE MILES OF WIRE UNDER
GROUND THAN OVER HEAD.
Over 5000, ooo, 900 Connections Made
in One WORKMANSHIP of Pic
tures-Selenium Cell Process.
From the Electrical Review.

From the Electrical Review.
Great strides have been made in the most
recent development-the automatic system
and that form of service is giving sausIac-
ton. 1t has been under trial in compare
lively small exchanges. but contracts nave
already been secured and INSTALLATIONS al
under way where the most rigid large Gu
pacity exactions will have to De met. LII
the manually operated exchanges the
wealth represented by the industry Is ap-
narent. While the Independent interests
are more or less welded together by the
bond of national organization, the securing
of data is not easy, and until clearing house
methods are adopted, and accurate Reports
are made to a central head, it will be hard
to show the amount Of business done by
independent companies. The growth OF inc
business however, may De judged by the
report of the American Telephone and Tele-
graph Company.
Some Telephone Statistics.
The gross revenue for the year 19O2
amounted to $13.277. 1913. The expenses,
including interest and taxes. were $. ~
1874 The total amount added to con-
struction and real estate by all the com
panies constituting this system was S7,-
3;36, 800. The total miles Of wire on January
l. 1903 were 2, 44S, $50. an increase for the
year of TIA, 731 miles. OF this increase 1,S4S
miles are represented by submarine cir
cults. which now total up to SOS miles.
One of the most interesting figures In this
table shows the extent to which under
ground construction has been carried out
during the past year. On January l, 1908.
there were LBS. 6S5 miles OF wire under
ground, or 219, 668 miles In excess of that
overhead, showing an increase In under
ground wire of $4,000 miles. as against
267 ,S77 miles increase for overhead lines
The estimated number Of exchange con-
nections made daily was 1922 951. or a
total for the year Of about 3.O02 900.
Independent Interests.
The Independent telephone interests claim
that this expansion has nearly been equal
ed. Under more practical management the
rates being charged by Independent tele
phone companies are based more on the
economic values of properties as a whole,
and competition is rapidly assuming a more
healthy condition. The independent inter-
ests are certainly now reaping the benef1t
of skilled employees. practical managers,
and highly trained electrical engineers.
Notwithstanding the efforts which are be-
ing made by each factor in the contest to
secure virgin territory and to acquire prop
critics which haye already been inaugural
ed, there is today trebled demand for
service. and the prospect, as voiced by all
of the operating companies. is that the
coming year will witness a still greater ex-
pansion than the year just closed.
Electrical Transmission Of Pictures
The following plan for the electrical
transmission of pictures is described in the
Observation-Disclosures Anzeiger: 1.-THE system
makes use of the Pollak-Virag rapid tele-
graph recorder and selenium cell for eff
fecting the necessary variations in inten-
sity of illumination. At each station two
telephone receivers are connected to
small mirror so as to vibrate this in two
directions. Corresponding telephone re-
ceivers are connected together. and within
each circuit is placed a revolving contact
maker. One of these contact makers makes
and breaks the circuit a certain number of
times for each revolution. and this of
course, sets up corresponding vibrations of
the two telephone receivers in that line.
The other breaker does not actually break
the circuit but Introduces q gradually in
creasng resistance. starting at zero and
rising to a maximum. and then dropping to
zero again. The effect of this is to produce
a comparatively slow motion of the two
telephone diaphragmS connented in that
circuit. When these two contact makers.
which are connected to the same shaft are
revolved. beam OF light. reflected from a
suitable source upon screen, will travel
gradually over the entire screen; starting
at one end, working its way back and
forth to the other. and then jumping to the
first point again. The method Of transmit
ting Is this:
Method Of Transmission.
"a beam OF light from an arc lamp is al
lowed to fall on the mirror at the sending
station. BY a suitable grouping of lenses.
the beam is thrown horizontally through
q Photographic negative, and is then To-
cused on a selenium cell. The effect of this
win be to vary the current In the circuit