a gravity tank on the roof or a
pressure tank in the basement. (From Thomas E. Brown, Jr., "The American
Passenger Elevator," _Engineering Magazine_ (New York), June 1893, vol. 5,
p. 340.)]

European elevator development--notwithstanding the number of American
rope-geared hydraulic machines sold in Europe in the 10 years or so
preceding the Paris fair of 1889--was confined mainly to variations on the
direct plunger type, which was first used in English factories in the
1830's. The plunger elevator (fig. 16), an even closer derivative of the
hydraulic press than Armstrong's crane, was nothing more than a platform
on the upper end of a vertical plunger that rose from a cylinder as water
was forced in.

There were two reasons for this European practice. The first and most
apparent was the rarity of tall buildings. The drilling of a well to
receive the cylinder was thus a matter of little difficulty. This well had
to be equivalent in depth to the elevator rise. The second reason was an
innate European distrust of cable-hung elevator systems in any form, an
attitude that will be discussed more fully farther on.

THE ELECTRIC ELEVATOR

At the time the Eiffel Tower elevators were under consideration, water
under pressure was, from a practical standpoint, the only agent capable of
fulfilling the power and control requirements of this particularly severe
service. Steam, as previously mentioned, had already been found wanting in
several respects. Electricity, on the other hand, seemed to hold promise
for almost every field of human endeavor. By 1888 the electric motor had
behind it a 10- or 15-year history of active development. Frank J. Sprague
had already placed in successful operation a sizable electric trolley-car
system, and was manufacturing motors of up to 20 horsepower in commercial
quantity. Lighting generators were being produced in sizes far greater.
There were, nevertheless, many obstacles preventing the translation of
this progress into machinery capable of hauling large groups of people a
vertical distance of 1,000 feet with unquestionable dependability.

The first application of electricity to elevator propulsion was an
experiment of the distinguished German electrician Werner von Siemens,
who, in 1880, constructed a car that successfully climbed a rack by means
of a motor and worm gearing beneath its deck (figs. 17, 18)--again, the
characteristic European distrust of cable suspension. However, the effect