rt that the true solution of this problem
lay in the continuous treatment of the material, with the maximum
employment of natural forces and the minimum of manual labor and
generated power. Hence, all his conceptions followed this general
principle so faithfully and completely that we find in the plant
embodying his ideas the forces of momentum and gravity steadily in
harness and keeping the traces taut; while there was no touch of the
human hand upon the material from the beginning of the treatment to its
finish--the staff being employed mainly to keep watch on the correct
working of the various processes.

It is hardly necessary to devote space to the beginnings of the
enterprise, although they are full of interest. They served, however, to
convince Edison that if he ever expected to carry out his scheme on the
extensive scale planned, he could not depend upon the market to supply
suitable machinery for important operations, but would be obliged to
devise and build it himself. Thus, outside the steam-shovel and such
staple items as engines, boilers, dynamos, and motors, all of the
diverse and complex machinery of the entire concentrating plant, as
subsequently completed, was devised by him especially for the purpose.
The necessity for this was due to the many radical variations made from
accepted methods.

No such departure was as radical as that of the method of crushing the
ore. Existing machinery for this purpose had been designed on the
basis of mining methods then in vogue, by which the rock was thoroughly
shattered by means of high explosives and reduced to pieces of one
hundred pounds or less. These pieces were then crushed by power directly
applied. If a concentrating mill, planned to treat five or six thousand
tons per day, were to be operated on this basis the investment in
crushers and the supply of power would be enormous, to say nothing of
the risk of frequent breakdowns by reason of multiplicity of machinery
and parts. From a consideration of these facts, and with his usual
tendency to upset traditional observances, Edison conceived the bold
idea of constructing gigantic rolls which, by the force of momentum,
would be capable of crushing individual rocks of vastly greater size
than ever before attempted. He reasoned that the advantages thus
obtained would be fourfold: a minimum of machinery and parts; greater
compactness; a saving of power; and greater economy in mining. As this
last-named operation pr