ENGINE No. S3. 137 



Engine No. 33 consists of two independent engines which 

 were tested simultaneously. These engines are single-acting 

 with vertical unjacketed cylinders, and provided with a single 

 piston valve fitted with ring packing, one valve serving for 

 both high- and low-pressure cylinders. A jet condenser is used 

 which is common to both engines ; and it is operated by an inde- 

 pendent air-pump, which takes steam from the main supply 

 pipe. The boiler feed-pump is also supplied from the main 

 pipe. The quantity of steam used by these two pumps was 

 determined by independent tests and allowed for. Steam is 

 furnished by water tube boilers ; and a calorimeter test showed 

 in one case T 7 n of 1% of moisture, and in the other I T L %. The 

 valves and pistons of both engines were practically tight. The 

 load consisted of dynamos employed in electric lighting. One 

 test was made with the engines running condensing, and an- 

 other running non-condensing, the condenser being stopped. 



The difference in economy of these engines, due to the use 

 of a condenser not allowing for steam used by air-pump, is 

 represented by 3.61 Ibs. of feed-water per I. H. P. per hour, 

 which, in round numbers, is 20% of the quantity used when 

 the engine was run condensing. The results of these tests can- 

 not be passed by without noticing the marked difference in the 

 porportion of steam accounted for at the cut-off under the two 

 conditions of operation; and the loss of steam between the 

 high-pressure cylinder and low-pressure cylinder in both cases. 



