48 BULLETIN 173, U. S. NATIONAL MUSEUM 



ERICSSON STEAM ENGINE, 1864 



U.S.N.M. no. 308672 ; original patent model ; transferred from the United States 

 Patent OflSce; not illustrated. 



This model was filed with the application for Patent no. 41612, 

 issued to John Ericsson, February 16, 1864. 



This model shows a horizontal reciprocating steam engine to the 

 piston of which is linked a rolling weight, which has a corresponding 

 reciprocating motion but always moves in a direction opposite to that 

 of the piston. The intention of the inventor was to diminish the con- 

 cussion and shaking of a marine engine bed caused by the starting 

 and stopping of the mass of the piston, piston rods, and cross head 

 by adding a similar reciprocating mass moving in the opposite direc- 

 tion. 



This model was made to demonstrate the principle involved in the 

 invention. It is driven by a spring motor and is mounted on rollers 

 so that it is free to move if there is any tendency to do so. The 

 counterbalancing weight rolls back and forth in the hollow wooden 

 base of the model. 



A brass plate on the model is engraved "J. Ericsson, Inventor, 

 1863." 



HORIZONTAL STEAM ENGINE, 1864 

 Plate 13, Figure 1 



U.S.N.M. no. 310241 ; original ; gift of the Southern Railway System ; photograph 

 no. 31026. 



This engine was built in 1864 at the Alexandria, Va., shops of the 

 United States Military Railroad Department under the direction of 

 W. H. McCafferty, master mechanic. It was used to furnish power 

 to the machine shops of the then Alexandria & Orange Railroad 

 and was continued in the same service to 1921. The engine is 

 typical of the best construction of simple stationary steam engines 

 as they were built in 1864 and for many years thereafter. 



The engine consists of a 12-inch diameter by 24-inch horizontal 

 cylinder bolted to a rectangular box frame of cast iron mounted upon 

 a low brick foundation. The crankshaft turns in one pillow block on 

 the frame and an outboard bearing block, which is carried on a brick 

 and timber base. The shaft carries a slender flywheel, 10 feet in 

 diameter, and a wide face belt pulley, 6 feet in diameter. The fly- 

 wheel and pully turn in a pit between the frame and the outboard 

 bearing. The cross-head guide is of the double-V type and is sup- 

 ported upon turned pillars rising from the frame. The valve is a 

 long slide valve, H-shape in plan, and in effect a simple B-valve. 

 It is driven from an eccentric on the shaft by a hook-and-latch eccen- 



