that time had not the
shadow of an idea as to what the principles of a multiple arc system
should be, enabling millions of lamps to be lighted off distributing
circuits, each lamp independent of every other; but at Menlo Park at
that remote period in the seventies Mr. Edison's mathematician was
formulating the inventor's conception in clear, instructive figures;
"and the work then executed has held its own ever since." From the
beginning of his experiments on electric light, Mr. Edison had a
well-defined idea of producing not only a practicable lamp, but also
a SYSTEM of commercial electric lighting. Such a scheme involved the
creation of an entirely new art, for there was nothing on the face of
the earth from which to draw assistance or precedent, unless we except
the elementary forms of dynamos then in existence. It is true, there
were several types of machines in use for the then very limited field of
arc lighting, but they were regarded as valueless as a part of a great
comprehensive scheme which could supply everybody with light. Such
machines were confessedly inefficient, although representing the
farthest reach of a young art. A commission appointed at that time by
the Franklin Institute, and including Prof. Elihu Thomson, investigated
the merits of existing dynamos and reported as to the best of them: "The
Gramme machine is the most economical as a means of converting motive
force into electricity; it utilizes in the arc from 38 to 41 per cent.
of the motive work produced, after deduction is made for friction
and the resistance of the air." They reported also that the Brush arc
lighting machine "produces in the luminous arc useful work equivalent to
31 per cent. of the motive power employed, or to 38 1/2 per cent. after
the friction has been deducted." Commercial possibilities could not
exist in the face of such low economy as this, and Mr. Edison realized
that he would have to improve the dynamo himself if he wanted a better
machine. The scientific world at that time was engaged in a controversy
regarding the external and internal resistance of a circuit in which
a generator was situated. Discussing the subject Mr. Jehl, in his
biographical notes, says: "While this controversy raged in the
scientific papers, and criticism and confusion seemed at its height,
Edison and Upton discussed this question very thoroughly, and Edison
declared he did not intend to build up a system of distribution in which
the external re