120
ELECTRIC LIGHTING.
will diminish, not in direct proportion, but in progressive proportion to the excess of power employed. Thus, if 80 horsepower are required to produce 15,000 units of light at one lamp,
and
is, by division, reduced to 200 units, 160 horseproduce not simply 400 units, but a much larger proportion, which will increase, not by addition but by multiplication,
if
power
the light
will
in proportion to the excess of power employed. It is, therefore, not impossible to obtain a divided light with a certain intensity, but on condition that the quantity of electricity produced shall be raised to a power much greater than that which will give a
single light representing the same number of candles. The question is to ascertain the proportion between the
two
terms, that is to say, whether the amount of power required for useful division be not out of proportion with the result obtained,
or in other words, if enormous apparatus would not be required an inconsiderable effect. This reduces the problem to the
for
and maintenance. The question may be 80 horse-power produces a light of 15,000 candles in a single lamp, how many horse-power would be required to bring up the light to the same value of 15,000 candles when total cost of erection
thus stated
:
If
divided
among several lamps ? Edison is seeking for the solution of this problem, which it would seem he has not yet found. This is the one important Edison has also to invent a generator of unheard-of question. power, and in this he says he is sure of succeeding. But in the meantime he has to try those which are at present in use, in order, no doubt, to find which comes nearest to his ideal, that it may supply the most advantageous data for constructing his own.
EFFECTS OF THE RESISTANCE OF EXTERNAL CIRCUITS.
If
we were
to take into consideration only the proper re-
sistance of the conductors
evident that the
composing an external
maximum
circuit, it
of electric intensity, yielded by the generator, would be obtained when the external circuit
is