214 ENGINE TESTS. 



Engine No. 53 is a horizontal tandem compound, with un- 

 jacketed cylinders and jet condenser operated by an indepen- 

 dent air-pump. The steam from the air-pump was taken from 

 an auxiliary boiler. The boilers are of the water-tube vertical 

 type, furnishing steam slightly superheated. The steam passes 

 through a reservoir at the engine, which is drained by a trap 

 discharging to waste. The valves and pistons of both cylin- 

 ders were found to be in fairly good condition throughout. 

 The load on the engine was rubber-grinding machinery and 

 somewhat variable in its character. 



The economy shown by this test, 15.78 Ibs. per I. H. P. per 

 hour, is rather low compared with other compound engines of 

 this type. The explanation of this result is found in part, at 

 least, in the small ratios of volumes of the two cylinders. The 

 diagrams show the variable character of the load. 



