52 BULLETIN 173, U. S. NATIONAL MUSEUM 



iiecting rod, and the other end slides and turns in a socket in the skirt 

 of the piston. Turning the piston causes two longitudinal grooves 

 in the piston to register periodically with exhaust and steam ports in 

 the cylinder wall. 



MAYHEW DIAPHRAGM STEAM ENGINE, 1879 



U.S.N.M. no. 308705 ; original patent model ; transferred from the United States 

 Patent Office; not illustrated. 



This model was submitted with the application for the patent 

 issued to Theophilus Mayhew, of New York, N. Y., July 8, 1879, 

 no. 217392. 



The engine consists of a hemispherical cuplike chamber over the 

 concave opening of which is stretched a flexible diaphragm. This 

 chamber connects to a valve chest in which a flat plate valve works 

 over the intake and exhaust ports. A lever extends from the frame 

 of the machine over the diaphragm upon which a projection of the 

 lever rests. Inflation and deflation of the diaphragm by admitting 

 and exhausting steam raise the lever and permit it to fall by its 

 own weight. A system of cranks and springs actuated by the lever 

 operates the valve. The engine was designed as a simple device for 

 operating churns and similar machines. 



GRAHAM STEAM ENGINE, c. 1880 

 U.S.N.M. no. 310898 ; model ; presented by C. F. Germeyer ; not illustrated. 



This model is of a type of small oscillating steam engine designed 

 and built by William Graham, of Carlisle, Pa., about 1880. Built in 

 sizes of 5 to 10 horsepower, these engines were popular in central 

 Pennsylvania for small shop power. 



On the oscillating cylinder of the engine is a cylindrical valve 

 chest containing a cylindrical rocking valve in the form of a "rolled- 

 up" D-valve. The valve is rocked by the motion of the cylinder, 

 through the action of an adjustable valve gear, which moves on a 

 pivot fixed to the stationary base of the engine. 



SCIPLE PORTABLE STEAM ENGINE, 1880 



U.S.N.M. no. 308710 ; original patent model ; transferred from the United States 

 Patent Office; not illustrated. 



This model was submitted with the application for the patent 

 issued to Harry M. Sciple, Selinsgrove, Pa., February 10, 1880, no. 

 224481. 



The model represents a small vertical steam engine designed to 

 have the pedestal, cylinder, and steam chest cast in one piece for 

 lightness of construction. The cross head and cross-head guides are 

 located above the cylinder so that a connecting rod much longer than 



