76 Transactions of the American Institute. 



wliich caused the differences in coal. The steam was drier during 

 the trial of the Harris engine. These observed facts are proved also 

 by the meter and indicator measurement of the water (see lines j? 

 and q^ table No. 2), for only 79.47 per cent of the water pumped 

 into the boiler was present as steam in the cylinder at the termina- 

 tion pf tlie stroke in the Babcock and Wilcox engine, while the 

 Harris engine showed 90.99 per cent (see lines r). The deficiencies 

 in the two cases show the amount of water present with the steam, 

 and equaled, therefore, 20.53 per cent of the whole in the Babcock 

 and Wilcox engine, and 9,01 per cent for the Harris engine. 



The fly-wheel of the Babcock and Wilcox engine was evidently 

 heavier than that of the Corliss engine. The difference in weight 

 was estimated at 8,000 pounds. 



The tables shoM- tlie actual results of the trials, without any con- 

 sideration whatever of the matters last mentioned. 



The trials of the regulating apparatus of the engines were, from 

 want of time, not made as full as was at first anticipated. In. 

 connection wuth one of the exhibitors, I had designed an instrument 

 to register the speed, but it was not completed by the manufac- 

 turer. . The regulation was tested by the judges and myself, by 

 holding the governor out of position, thus increasing or decreas- 

 ing the speed of the engine, and then suddenly permitting the 

 goverjior to operate again. 



All of the engines did well on this test ; but the Harris and 

 Delamater engines were particularly prompt in bringing the shafting 

 again to speed. 



The speed of each engine, wlien doing its work under diftcrent 

 Bteam pressures, was tested, after its tiial for economy, by running 

 down the steam pressure until the speed of the engine slackened. 



The results of these experiments are shown in the annexed table, 

 in which two columns refer to each engine, and show the steam 

 pressure and revolutions at the end of each minute during the trial. 



steam. Revolutions, 



Babcock & Wilcox 62 61 



Babcock & Wilcox 58 59 



Babcock & AVilcox 54 58 



Babcock A: Wilcox 50 58 



Babcock & Wilcox 45 58 



Babcock & Wilcox 40 56 



Babcock & Wilcox 37.5 53 



Babcock & AVilcox 34.5 49 



