gs, yet they could be stopped with a smoothness
and precision unattainable earlier with systems in which the valves were
controlled by an endless rope, worked by the operator. It was almost
completely silent, and when the cylinder was placed vertically in a well
near the shaft, practically no valuable floor space was occupied. But most
important, the length of rise was unlimited because no drum was used. As
greater rises were required, the multiplication of the ropes and sheaves
was simply increased, raising the piston-car travel ratio and permitting
the cylinder to remain of manageable length. The ratio was often as high
as 10 or 12 to 1, the car moving 10 or 12 feet to the piston's 1.

In addition to its principal advantages, the hydraulic elevator could be
operated directly from municipal water mains in the many cities where
there was sufficient pressure, thus eliminating a large investment in
tanks, pumps and boilers (fig. 14).

By far the greatest development in this specialized branch of mechanical
engineering occurred in the United States. The comparative position of
American practice, which will be demonstrated farther on, is indicated by
the fact that Otis Brothers and other large elevator concerns in the
United States were able to establish offices in many of the major cities
of Europe and compete very successfully with local firms in spite of the
higher costs due to shipment. This also demonstrates the extent of error
in the oft-heard statement that the skyscraper was the direct result of
the elevator's invention. There is no question that continued elevator
improvement was an essential factor in the rapid increase of building
heights. However, consideration of the situation in European cities, where
buildings of over 10 stories were (and still are) rare in spite of the
availability of similar elevator techniques, points to the fundamental
matter of tradition. The European city simply did not develop with the
lack of judicial restraint which characterized metropolitan growth in the
United States. The American tendency to confine mercantile activity to the
smallest possible area resulted in excessive land values, which drove
buildings skyward. The elevator followed, or, at most, kept pace with,
the development of higher buildings.

[Illustration: Figure 14.--In the various hydraulic systems, a pump was
required if pressure from water mains was insufficient to operate the
elevator directly. There was either