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Scientific American Supplement, No. 315, January 14, 1882 by Various
page 35 of 143 (24%)
stating that a result so high as 4,000 candles evolved for 40,000
foot-pounds absorbed has recently been obtained--an efficiency six or
seven times greater than the record of six years ago. In accepting
this statement we must not lose sight of the extreme probability that
such effects were evolved under conditions rarely if ever found in
common practice. Of course, I now refer to the arc system. The volume
of light so generated is incomparably greater than by any other known
method, though in subdivision the limit is sooner reached.

Mr. Hawkesworth--Let me ask you a question, please. Supposing that it
required a one-horse power to produce an arc light of, say, 2,000
candles, would it be possible to produce ten arc lights of 200 candles
each?

Mr. Daft--No, sir; I will tell you why. It would, if no other element
than the simple resistance of the arcs opposed the passage of a
current; then a machine that would produce an inch arc in one light,
if placed on a circuit of sixteen lamps would give to each an arc
one-sixteenth of an inch long naturally; but another difficulty here
presents itself in the shape of a resisting impulse of considerable
electromotive force in the opposite direction, apparently caused by
the intense polarity of the two terminals. The resistance of the arc
itself varies much according to the volume of current used being
usually small with a large quantity of current, and greater with a
current of tension; but this opposing element is always found, and
appears to be the only real obstacle in the way of infinite
subdivision.

Almost every objection which human ingenuity could suggest has been
urged against lighting by electricity, but fortunately electricians
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