Part 7

Mechanical transmission of power by wire rope was a well developed practice at this time, involving in many instances high powers and distances up to a mile. To attempt this system in the Eiffel Tower, crowded with structural work, machinery and people, was another matter.

According to Otis Elevator Company, the final price, because of extras, was $30,000.

In Pall Mall Gazette, as quoted in The Engineering and Building Record and the Sanitary Engineer, May 25, 1889, vol. 19, p. 345.

From speech at annual summer meeting of Institution of Mechanical Engineers, Paris, 1889. Quoted in Engineering, July 5, 1889, vol. 48, p. 18.

Located near the Tower, built for the Paris fair of 1878.

Improved oil-well drilling techniques were influential in the intense but short burst of popularity enjoyed by direct plunger systems in the United States between 1899 and 1910. In New York, many such systems of 200-foot rise, and one of 380 feet, were installed.

An obvious question arises here: What prevents a plunger 200 or 300 feet long and no more than 16 inches in diameter from buckling under its compressive loading? The answer is simply that most of this length is not in compression but in tension. The Edoux rams, when fully extended, virtually hung from the upper car, sustained by the weight of 500 feet of cable on the other side of the sheaves. As the upper car descended this effect diminished, but as the rams moved back into the cylinders their unsupported length was correspondingly reduced.

M. A. Ansaloni, "The Lifts in the Eiffel Tower," quoted in Engineering, July 5, 1889, vol. 48, p. 23. The strength of steel when drawn into wire is increased tremendously. Breaking stresses of 140,000 p.s.i. were not particularly high at the time. Special cables with breaking stresses of up to 370,000 p.s.i. were available.

Transcriber's Notes:

Passages in italics are indicated by underscore.

The original was printed in two columns per page.

Illustrations have been moved to the nearest paragraph break.

The following misprints have been corrected: "Trevethick's" corrected to "Trevithick's" (page 5) "then" corrected to "than" (page 14) "smiliar" corrected to "similar" (page 31)