REVIEW OF FEED-WATER TESTS. 275 



In Engine No. 54, which is a single-valve compound, the feed- 

 water consumption was nearly constant for loads of 242.9 H. P. 

 and 187.5 H. P. ; but it was increased from 21.14 Ibs. to 24.99 

 Ibs. by dropping the load to 103.4 H. P. In Engine No. 41, a 

 single-valve compound condensing, the consumption was in- 

 creased from 19.1 Ibs. to 22.74 Ibs. by reducing the load from 

 196.8 H.P. to 90.5 H.P. In Engine No. 45, which is a double- 

 valve compound condensing, the consumption was increased 

 from 15.71 Ibs. to 17.22 Ibs. by reducing the load from 244.5 

 H. P. to 123.4 H. P. 



Very little information of definite character is furnished by 

 the tests as to the effect of size of cylinder on economy. Most 

 of the smaller engines given are of the single-valve class, with 

 shaft governors, running at high speed ; and although these 

 generally show less economy than the larger engines, it would 

 hardly be fair to attribute it to the smaller size of cylinder 

 when other differences of condition are known to be of much 

 importance. Two cases are given for Corliss engines which 

 seem to show that a considerable difference of size has no 

 appreciable effect. These are Engine No. 2, having a 28.5" 

 \ .V.).5" non-condensing cylinder, and Engine No. 31, which 

 had 2-10" x 42" cylinders. The former gave a horse-power for 

 25.8 Ibs. of feed- water per hour ; and the latter, when working 

 at about the same cut-off, for 25.9 Ibs. per hour, or practically 

 the same, result. Cylinder condensation and leakage is 2.1% 

 greater in the case of the smaller engine ; and this fact fur- 

 nishes a slight indication that the smaller engine was the more 

 wasteful. 



It needs but a glance at the results of the various tests to 

 show that the 4-valve engines are more economical as a type 

 than those having a less number of valves; and this is true 

 whether they are simple or compound, and whether condensing 

 or non-condensing. The single-valve compound non-conden- 

 sing Engine No. 54, compared with the 4-valve compound 

 non-condensing Engine No. 46, shows a better result, some 

 1'/ f ; but it will be observed that the former works under a 

 pressure of 165 Ibs., while the pressure in the latter case is 135. 



