e / E = w / W = 1/2

which law had been frequently construed, by Verdet (Theorie Mecanique
de la Chaleur) and others, to mean that one-half was the maximum
theoretical efficiency obtainable in electric transmission of power, and
that one half of the current must be necessarily wasted or turned into
heat. The lecturer could never be reconciled to a law necessitating such
a waste of energy, and had maintained, without disputing the accuracy of
Jacobi's law, that it had reference really to the condition of maximum
work accomplished with a given machine, whereas its efficiency must be
governed by the equation:

e / E = w / W = nearly 1

From this it followed that the maximum yield was obtained when two
dynamo machines (of similar construction) rotated nearly at the same
speed, but that under these conditions the amount of force transmitted
was a minimum. Practically the best condition of working consisted in
giving to the primary machine such proportions as to produce a current
of the same magnitude, but of 50 per cent, greater electromotive force
than the secondary; by adopting such an arrangement, as much as 50 per
cent, of the power imparted to the primary could be practically received
from the secondary machine at a distance of several miles. Professor
Silvanus Thompson, in his recent Cantor Lectures, had shown an ingenious
graphical method of proving these important fundamental laws.

The possibility of transmitting power electrically was so obvious that
suggestions to that effect had been frequently made since the days of
Volta, by Ritchie, Jacobi, Henry, Page, Hjorth, and others; but it
was only in recent years that such transmission had been rendered