The Locomotive - Lighthouse Survival Blog

-[56 THE LOCOMOTIVE. [October,
Tlie decliuation axis of the instrument is 12 inches in diameter and 11 feet 6 inches long,
and weighs a ton and a half. The polar axis is 15 inches in diameter and 13 feet 6
inches long, and weighs three tons and a half. Both these axes are of steel, and they
run on ball bearings. The weight of that part of the telescope which must be moved by
the clock (in following the stars across the heavens) is 20 tons. The clock itself weighs
a ton and a half. It is situated in the upper part of the pedestal, or " column," of the
telescope. The main driving wheel by which the clock is geared to the polar axi^is
•eight feet in diameter. The clock is wound automatically by an electric motor, and is
•controlled by a double conical pendulum. The column and head of the telescope are
made of cast-iron ; they are 43 feet high, over all, and weigh 50 tons. The total weight
of the instrument is 75 tons. All the " quick motions " and " slow motions " and clamps
•can be operated by hand by the observer, and also by electric motors controlled by a
switchboard within easy reach. The telescope can also be fully controlled by the assist-
ant astronomer, who is stationed on the balcony surrounding the head of the telescope.
This balcony, and the clock room, which is entered from it, are reached by a spiral staircase
at the south side of the column. The mounting of this telescope was made by
Messrs. Warner & Swasey, of Cleveland, Ohio, and the object-glass is being made by
Messrs. Alvan Clark's Sons, of Cambridgeport, Mass. The 26-inch telescope in the U.
S. Naval Observatory at Washington, and the 36-inch one in the Lick Observatory, were
made by the same firms.
The Ferris Wheel.
The RevieiD of Reviews for September, publishes an exceedingly interesting article
on " Engineer Ferris and His Wheel," descriptive of that singular exhibition of American
ingenuity and progress. The writer says :
Given the circumstances, in no other country than America would the wheel have
ever been built. It took three years to complete the Eiffel Tower. Even here it took
two years to build the St. Louis bridge. Both were comparatively simple work. The
huilder of the Ferris wheel had not only to construct a work equaling these, but in
such a way that it would move, and, moreover, move perfectly — a far greater problem.
On December 28th every scrap of iron and steel used in the wheel was " pig." On
June 21st, less than six months later, 2,200 tons of this " pig." converted into a revolving
mechanism as perfect as the pinion wheel of an Elgin watch, began to turn on its
70-tou axis, and has been turning without let or hindrance, without creak or crack, ever
since.
It is not easy for the mind to grasp the stupendous nature of this undertaking. The
wheel itself is two hundred and fiftj|feet in diameter ; at its highest point it is two
hundred and sixty-eight feet above the earth. That is to say, if Bunker Hill monument
was used as a yardstick to measure it, the towering monolith would fall short fifty feet.
If the wheel were set in Broadway, by the side of Trinity spire, it would lift the pas-
sengers of its cars to a level with the apex of that soaring steeple. The obelisk of
Luxor or Trajan's pillar, at Rome, would not be long enough to serve for a radial spoke.
Then, again, as to its enormous weight. The Niagara cantilever, just below the
Falls, was looked upon as an engineering wonder when it was built. Its construction
required three years. The Ferris wheel was built in five months, and its weight is four
times that of the Niagara bridge. The St. Louis bridge was another wonder, and its
weight is about equal to that of the big wheel complete. The Cincinnati cantilever is
another huge bridge ; it is 1,300 feet, a quarter of a mile, long, and it would about bal-