150 ENGINE TESTS. 



Steam is supplied from vertical boilers, which gave steam that 

 was at times slightly superheated, and at other times in its ordi- 

 nary condition. The feed-water was measured on the test by 

 water-glass observations, the water being first pumped to a high 

 point, then shut off, and the test continued until the boilers 

 needed replenishing. The water drained from the jackets 

 amounted to 248 Ibs. per hour, or in round numbers, 7% of the 

 total quantity used by the engine. The load consisted mainly 

 of rubber grinding machinery. 



The variable character of the load, and the short duration of 

 the test, make the results less accurate than they would be 

 if the load had been steady and the water had been measured 

 for a longer period. The sample indicator diagrams which are 

 here presented, owing to the fluctuating load, must be regarded 

 as showing the general distribution of the steam in the cylin- 

 ders rather than precise average samples of the work. 



When the jackets were shut off, the distribution of the 

 steam was affected in a noticeable degree. The difference 

 between the steam shown at release and cut-off was greatly 

 increased. 



