Co-creator of the first commercially produced automobile (1861-1938). TLS signed in pencil, “Duryea,” one page, 8.5 x 11, personal letterhead, April 4, 1932. Letter to "Mr. Thwing," describing a type of vacuum engine. In part: "The Morey is a double engine. Vacuum type below the piston an explosion type above. Made from the British drawings which show only the vacuum type. (We dared not depart too much from them lest we be criticised. Morey's explanation of the explosion type reveals more power than these limber connecting rods will stand. This we proved by our scanty tests of it.) Morey sensed that a full cylinder of explosive mixture was not needed to drive the air out of the cylinder. So he introduced a charger piston. This is perforated and carried by friction, in contact with the true piston on the up stroke to a point '1/8 stroke to 1/4 stroke' below upper DC. There the charger stands while the piston travels on, the air intake valve at the bottom closing as the charger stops. At the same time the fuel mixture valve opens so the further movement of the piston draws in explosive mixture between the charger and piston. As a vacuum engine, this when fired, simply expels the air thru the flap valve at the bottom; water immediately introduced cools down the remainder and the walls and the air freely above drives the piston down. This completes the cycle as a vac eng.
But Morey saw that by extending the cylinder above and fitting a head and stuffing box and by fitting an up-opening valve in the piston he could get much of the explosion above the piston. So as a combined engine the operation below the piston is same as before. But on the up stroke the piston compresses the full cyl content—air, gas or what not. Part of the explosion goes up thru into this comprest content. Adds to its mass and heats it much. This gives far more power on the down stroke than wud atmospheric air. At the bottom a stop lifts the piston valve and any excess of pressure remaining, exhausts." The reverse of the page has a printed essay by Duryea entitled 'Some Money & Depression Facts. The Right Remedy,' discussing methods of taxation to relieve the Great Depression. In fine condition, with a small edge tear passing through Duryea's signature. Accompanied by a small booklet published by Duryea, entitled "The Real Pioneer."
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