Page 8

THE INTERNA TIONAL EXHIBITION, I876.
more than by Mr. Corliss' proposition. After considerable delay, Mr. Corliss
was then unanimously requested to renew his offer, and in June, i875, eleven
months before the opening, a contract was closed with him for the work, giving
him only about ten months to construct that for which there had not as yet
been even the first sketch prepared. How promptly the work has been per-
formed, will be apparent when we state that on the day fixed by the contract-
April I7, 1876-the engine was up in place, steam was turned on, and it was
run for some time with perfect success.
The special characteristics of the Corliss Engine as compared with other
steam engines may. be said to consist in the valve gear, the form of valve
and
the peculiar method adopted by which steam is freely admitted at the full
boiler
pressure and discharged after use, without presenting any resistance to the
piston. Independent parts are used for admitting and exhausting the steam
with four separate valves, the steam being cut off from the cylinder entirely
by
the main steam valves without the employment of any supplementary valves.
The steam valves are opened against the resistance of springs, and a liberating
gear is called into play, disconnecting the valves and leaving them free
to be
closed by the springs. These springs are brought to rest without shock after
closing by means of an air cushion formed by a small cylinder with a closed
bottom, in which a piston is fitted to work easily, a certain amount of air
being
imprisoned just as this piston approaches the bottom, acting as a cushion
and
preventing any shock. The valves of admission are regulated by direct connection
with the governor, thus controlling the speed of the engine without the use
of
a throttle-valve in the main supply-pipe.
The principal inventions which distinguish the Corliss Engine were devised
in i848 and patented in 1849, a beam engine of 260 horse-power having been
constructed with the new improvements for use in Providence. The success
of
this engine was so great as to induce the parties with whom Mr. Corliss was
asso-
ciated to erect new works in the summer of I848 for the purpose of extending
their business. The machine-shop then built, covering an acre of ground,
is yet
standing intact. About two years after this time, a course of patent litigation
commenced, extending over a period from i85o to i865, involving the firm
and
very much embarrassing its operations. Mr. Corliss from being the defendant
in
the first place, was afterwards obliged to take the place of plaintiff to
maintain
8