REVIEW OF FEED- WATER TESTS. 277 



I. H. P. per hour, and when exhausting into the receiver it 

 was, of course, a much larger quantity ; but in spite of this 

 the extra power produced by the use of the steam in the low- 

 pressure cylinder was such that the entire consumption of 

 the engine and condenser was only 14.1 Ibs. per I. H. P. per 

 hour. 



One test on a compound engine is given, where the water 

 drained from jackets and receiver was pumped into a flue 

 heater, and the steam produced by its re-evaporation brought 

 back to the receiver and used in the low-pressure cylinder. 

 This is Engine Xo. 50. Under the circumstances of a compar- 

 atively low boiler pressure, which was 108.1 Ibs., the economi- 

 cal result obtained, which was 13.28 Ibs. per I. H. P. per hour, 

 must be considered excellent. The engine, however, was sup- 

 plied with superheated steam ; and this condition is, no doubt, 

 accountable, in some degree at least, for the result obtained. 

 It is doubtful whether the re-heating had any marked effect ; 

 because it appears that the steam accounted for in the L. P. 

 cylinder is .77 as against .889 in the H. P. cylinder, showing a 

 loss between the two of .119. If this is compared with Engine 

 No. 49, which is supplied with ordinary steam, and had no 

 re-heating feature, there is a difference between the two cylin- 

 ders of .106 ; so that there is no more loss in this case between 

 the cylinders than in Engine No. 50, which had the re-heating 

 system. 



1 lie evidence of the tests furnish some data upon the effect 

 of varying the receiver pressure in a compound engine, but 

 this data is not conclusive as applied to other engines. In the 

 case of Engine No. 51, three tests made with nearly the same 

 load and with a receiver pressure, ranging from 5.4 Ibs. above 

 the atmosphere to 12.9 Ibs., the cut-off in the low-pressure 

 cylinder being gradually shortened as the pressure increased, 

 showed a gradual reduction in the feed-water consumed per 

 I. II. P. per hour. With the lowest pressure, it was 12.29 Ibs., 

 and with the highest, 11.89 Ibs. In Engines No. 47 and 52, 

 where similar tests were made with three different receiver 

 pressures, practically the same result is produced at the two 



