CATALOG OF THE MECHANICAL COLLECTIONS 31 



Thomas Newcomen, of Dartmouth, England, with John Cawley 

 (or Galley) made the first successful atmospheric engines about 1712. 

 Though these engines incorporated most of the features of a successful 

 reciprocating steam engine and were a great advance over the Savery 

 engine (above), they infringed the broad patent granted to Savery 

 and were therefore made for several years under his patents. 



WATT PUMPING ENGINE, c. 1776 



U. S. N. M. no. 308130; colored drawing made from the engine; gift of A. W. 

 Willet ; not illustrated. 



The engine shown in the drawing is one of two engines designed 

 and built by Boulton and Watt for the Birmingham (England) Canal 

 Co. about 1776-78. The engines were erect3d at Smethwick and 

 employed to pump lockage water from the lower levels of the canal 

 to a summit at that point. One engine remained in use until 1892, 

 when it was replaced by a modern pumping plant. The company's 

 engineer, G. R. Gebb, caused the engine to be preserved and had it 

 reerected at the Canal Co.'s Ocker Hill Works, where it still remains 

 in working order. The donor, who succeeded Mr. Gebb, had the 

 drawings made from the engine for the James Watt Centenary Cele- 

 bration in 1919. 



The engine is a typical Watt beam engine with vertical, double- 

 acting cylinder, 32 inches in diameter and 8- foot stroke. The pump 

 cylinder is 29 inches in diameter. The speed was 13 strokes a minute 

 and the steam pressure 10 pounds per square inch. The engine is 

 equipped with a separate jet condenser and a 14-inch condenser air 

 pump operating from the beam. The drawing includes a section 

 through the lower valve chest showing the exhaust, intake, and equi- 

 librium valves. The valves are operated by a rod from the beam. 



The drawing is about 27 by 40 inches and is made to the scale of 

 % inch equals 1 foot. 



WATT PUMPING ENGINE, "OLD BESS", 1777 

 Plate 10, Figube 2 



U.S.N.M. no. 308469 ; model ; made in the Museum ; photograph no. 17143A. 



This model was made from a photograph and description of the 

 working model in the Science Museum, London. 



The engine "Old Bess" was built by Watt for the hardware factory 

 of Matthew Boulton at Soho, England. The factory was operated 

 by an overshot water wheel, 24 feet in diameter, 6-foot breast, and 

 the engine was used to pump water from the lower wheel race to the 

 flume above, to turn the wheel during dry seasons when the natural 

 flow of water was not sufficient. 



