CATALOG OF THE MECHANICAL COLLECTIONS IQl 



The engine has four single-acting, horizontal cylinders arranged in 

 a block like the chambers of a revolver. Connecting rods from the 

 four pistons connect to pins on crank disks on a common shaft. The 

 head ends of the four cylinders open into a drumlike exhaust cham- 

 ber. A rotary valve of peculiar construction revolves in the exhaust 

 chamber close to the ends of the cylinders and opens the cylinders 

 to the exhaust chamber or to the pressure inlet pipe, which forms 

 the hollow stem of the valve, in proper sequence. The hollow stem 

 of the valve passes out of the forward side of the exhaust chamber 

 through a gland and bearing. It carries a spur gear that meshes with 

 a pinion on a lay shaft, which parallels the cylinders and is turned 

 by a bevel gear pair at the crankshaft. 



CARPENTER COMPOUND HYDRAULIC ENGINE, 1878 



U.S.N.M. no. 309252 ; original patent model ; transferred from the United States 

 Patent Office ; not illustrated. 



The model was submitted with the application for the patent issued 

 to Oramill C. Carpenter, of Brookljai, N. Y., December 17, 1878, 

 no. 210915. 



The engine is essentially a hydraulic transmission, wliich takes 

 motion from eccentric cams on a central shaft turned by a steam 

 or other engine and transmits the motion to shafts on either side of 

 and parallel to the central shaft. The inventor designed the engine 

 to be applied to a streetcar, and the model is mounted in a miniature 

 nickel-plated car truck. 



It is a 4-cylinder engine with opposed cylinders in groups of two. 

 Single-acting plungers work in and out of the cylinders as the central 

 shaft is turned. The head of each cylinder leads directly to another 

 cylinder of reduced diameter in each of which a driven piston works 

 through a longer stroke in time with the short stroke of the driving 

 piston. Valves for the relief of an excess pressure of liquid and 

 spring-cushioned piston heads are described for smoother running. 



COLWELL DISULPHIDE OF CARBON GENERATOR AND ENGINE, 1879 



U.S.N.M. no. 308T6G; original patent model; transferred from the United States 

 Patent Office ; not illustrated. 



The model was submitted with the application for the patent issued 

 to William S. Colwell, of Pittsburgh, Pa., September 16, 1879, no. 

 219622. 



The model represents a reciprocating engine of more or less con- 

 ventional steam engine design in which the operating fluid is vapor- 

 ized carbon disulphide supplied by a boiler or generator and condensed 

 in an air-cooled condenser. The transfer of heat from the fire in 

 the boiler to the carbon disulphide and from the exhaust vapor to 

 the cooling air of the condenser is effected through water. Plumbago, 



