support of
this ingenious system are tenable and logical at the present moment; but
the trolley had its way except on a few lines where the conduit-and-shoe
method was adopted; and in the intervening years the volume of traffic
created and handled by electricity in centres of dense population has
brought into existence the modern subway.

But down to the moment of the preparation of this biography, Edison has
retained an active interest in transportation problems, and his latest
work has been that of reviving the use of the storage battery for
street-car purposes. At one time there were a number of storage-battery
lines and cars in operation in such cities as Washington, New York,
Chicago, and Boston; but the costs of operation and maintenance
were found to be inordinately high as compared with those of the
direct-supply methods, and the battery cars all disappeared. The need
for them under many conditions remained, as, for example, in places
in Greater New York where the overhead trolley wires are forbidden as
objectionable, and where the ground is too wet or too often submerged
to permit of the conduit with the slot. Some of the roads in Greater
New York have been anxious to secure such cars, and, as usual, the most
resourceful electrical engineer and inventor of his times has made
the effort. A special experimental track has been laid at the Orange
laboratory, and a car equipped with the Edison storage battery and other
devices has been put under severe and extended trial there and in New
York.

Menlo Park, in ruin and decay, affords no traces of the early Edison
electric-railway work, but the crude little locomotive built by Charles
T. Hughes was rescued from destruction, and has become the property
of the Pratt Institute, of Brooklyn, to whose thousands of technical
students it is a constant example and incentive. It was loaned in 1904
to the Association of Edison Illuminating Companies, and by it exhibited
as part of the historical Edison collection at the St. Louis Exposition.

CHAPTER XIX

MAGNETIC ORE MILLING WORK

DURING the Hudson-Fulton celebration of October, 1909, Burgomaster Van
Leeuwen, of Amsterdam, member of the delegation sent officially from
Holland to escort the Half Moon and participate in the functions of the
anniversary, paid a visit to the Edison laboratory at Orange to see
the inventor, who may be regarded as pre-eminent among those of Dutch
descent in this country. Found, as usual,