Watertown republican. [volume] (Watertown, Wis.) 1860-1906, 1880-09-29
ELECTRIC LIGHT.

| The editor of The North American Re
view has induced Mr.. Edison to "tell his
own tale in his own melodious way" and
the result is an interesting article over his
signature, which appears in the October
number of that periodical.
Mr.. Edison begins his article with a
few words to those who have expressed
their impatience at the delays in the per-
fecting of the electric light. The delays
which have occurred to deter its general
introduction are chargeable, he says, not
to any defects since discovered in the
original theory of the system in its prac-
tical workings, but to the enormous mass
of details which have to be mastered be-
fore the system can 60 into operation on
a large scale and on a commercial basis
as rival of the existing system of light
ming by gas. Important Improvements
have been brought about by these delays
in the direction of economy and simpli-
fication at almost every point in the sys-
tenn, as well as in the details of manufac-
turing the apparatus.
The lamp, the inventor tells us, has
been completely transformed. To quote
his words;
'"rhe perfected lamp consists of an
oval bulb of glass about five inches in
height, pointed at one end, and with short
stem, three quarters of an inch in diam
eter at the other Two wires of platinum
enter the bulb through the stem, sup
porting the loop or Q-shaped thread
of carbon, which is about two inches in
height. The stem is Theoretically sealed
~ IL, Il. A.
At its pointed end the bulb terminates in
an open tube through which the air in
the bulb is exhausted by means of a
mercury pump till not over one-millionth
part remains. The tube is then closed.
The outer extremities of the two plati-
mum wires are connected with the wires
of an electric circuit, and at the base of
the lamp is screw by which the circuit
is made or broken at pleasure. When
the circuit is made the resistance offered
to the passage of the electric current by
the carbon causes the loop to acquire
high temperature and to become incan-
descent, but as this takes place in
vacuum, the carbon is not consumed.
The life of carbon loop through which
current is passed continuously varies
from seven hundred and fifty to nine
hundred hours. With an intermitted
current the loop has an equal duration
of life, and as the average time an arti-
fcal light is used is five hours per day,
it follows that one lamp will last about
six months. Each lamp costs about
fifty cents, and when one fails another
may be easily substituted for it,
Another nj modification of tb a
system, introduced since the last author
lied accounts of the light was published,
as the substitution of dynamo-machines
for magnetic machines in the stations
from which the electricity is to be sup
piled to the several districts of city-a
change in the direction of simplicity and
economy. To the question which is so
often asked, when will public demon
stration of the working of the system be
made, the inventor replies:
"That such demonstration will in all
probability be made at Menlo Park with
in two months from this date. The time
which has elapsed since the preliminary
demonstration of last January has been
by no means season of inaction for the
promoters of this enterprise. There is
vast gulf between the most successful
laboratory experiment possible and the
actualization of the results of that expert
ment in commercial sense A prodigi-
Gus amount Of work was necessitated by
the establishment of factories for produc-
ing the lamps the generators and other
essential parts of the system in large
quantities, so as to be able to supply the
! first demand"
Mr. Edison goes into the particulars
concerning his lamp, giving statement
of it's advantages over gas in the matter
of simplicity in the management and
economy. He repeats what has already
been stated in The Herald concerning the
plans for lighting the cities. Estimates
are being made of the exact cost of
''plant'' in the different cities; contracts
are being negotiated for the manufacture
on large scale Of engines, dynamos,
lamps, wire and all the other supplies
needed for the practical introduction of
the system throughout the country.
0.--