ch light to give
a useful and economical degree of illumination; and each light to
be independent of all the others in regard to its operation and
extinguishment.

The opinions of scientific men of the period on the subject are well
represented by the two following extracts--the first, from a lecture at
the Royal United Service Institution, about February, 1879, by Mr. (Sir)
W. H. Preece, one of the most eminent electricians in England,
who, after discussing the question mathematically, said: "Hence the
sub-division of the light is an absolute ignis fatuus." The other
extract is from a book written by Paget Higgs, LL.D., D.Sc., published
in London in 1879, in which he says: "Much nonsense has been talked
in relation to this subject. Some inventors have claimed the power to
'indefinitely divide' the electric current, not knowing or forgetting
that such a statement is incompatible with the well-proven law of
conservation of energy."

"Some inventors," in the last sentence just quoted, probably--indeed,
we think undoubtedly--refers to Edison, whose earlier work in electric
lighting (1878) had been announced in this country and abroad, and
who had then stated boldly his conviction of the practicability of
the subdivision of the electrical current. The above extracts are good
illustrations, however, of scientific opinions up to the end of
1879, when Mr. Edison's epoch-making invention rendered them entirely
untenable. The eminent scientist, John Tyndall, while not sharing these
precise views, at least as late as January 17, 1879, delivered a lecture
before the Royal Institution on "The Electric Light," when, after
pointing out the development of the art up to Edison's work, and showing
the apparent hopelessness of the problem, he said: "Knowing something of
the intricacy of the practical problem, I should certainly prefer seeing
it in Edison's hands to having it in mine."

The reader may have deemed this sketch of the state of the art to be
a considerable digression; but it is certainly due to the subject to
present the facts in such a manner as to show that this great invention
was neither the result of improving some process or device that was
known or existing at the time, nor due to any unforeseen lucky chance,
nor the accidental result of other experiments. On the contrary, it was
the legitimate outcome of a series of exhaustive experiments founded
upon logical and original reasoning in a mind that had the courage an