42 BULLETIN 173, U. S. NATIONAL MUSEUM 



to the end of the cylinder. The space above the upper valve in each 

 chest was connected to the boiler steam pressure, the lower space to 

 the condenser. In each case the stem of the valve extended upward, 

 the stem of the lower valve passing through the upper valve and valve 

 stem. The valve-actuating mechanism was very lightly sketched in 

 the drawing, and the exact method of operation is not discernible. 

 It is fairly clear that a bracket bolted to each valve chest extended 

 upward and carried the pivots for two bell cranks, which were at- 

 tached to collars on the valve stems. A third bracket slightly aft of 

 the valve chests and just below the upper valve chest carried the 

 pivots of twc other bell cranks. These two bell cranks had their 

 afterarms drawn out and curved into hooks, which may have been 

 handles for manual operation of the valves or which may have en- 

 gaged with some valve-actuating mechanism not shown. Each of 

 these two bell cranks had two other arms connected by links to the 

 bell cranks on the valve chest brackets. The upper one operated the 

 steam valve of the upper end of the cylinder, opening it as it opened 

 the exhaust valve of the lower end. The lower crank opened the 

 exhaust valve of the upper end while it opened the steam valve of the 

 lower end, and vice versa. The crankshaft of the engine was directly 

 under the cross head and slightly below the top of the cylinder. The 

 crank was carried on the side of a 6-foot gear wheel, which meshed 

 with a 3-foot gear on the flywheel shaft. The flywheel sketched was 

 approximately 13 feet 6 inches in diameter. 



JAMES WATT ENGINE AT SAVANNAH, GA., 1815 



U.S.N.M. no. 309800 ; blueprint of drawing made from the engine ; gift of John 

 Rourke, Sr. ; not illustrated. 



This print is a side and end elevation of a 90 horsepower beam 

 engine, built by James Watt at Lancashire, England, in 1815. The 

 engine was brought to Savannah, Ga., and erected at the rice mills 

 of Messrs. McAlpin and Mclnnis, where it worked regularly to about 

 1900. In 1891 it was generally overhauled and repaired by Jolui 

 Rourke & Son, Novelty Iron Works, Savannah, when this drawing 

 was made. When the mill was dismantled about 1900 the engine 

 was stored by Mr. Rourke who recognized its historical value. Un- 

 fortunately it was destroyed by fire several years later. 



The engine had a 31-inch cylinder, 72-inch stroke, and operated 

 at 18 revolutions a minute on 8 pounds per square inch steam pres- 

 sure. It was equipped with a common jet condenser and a 24-inch 

 air pump. A boiler feed pump worked from the beam. The crank- 

 shaft and connecting rod were cast iron. 



