Report of Judges on Steam Engines. 55 



EXHIBIT B. 



Superintendent's Office, American Institute Exhibition, ) 

 IS'ew York, Ootoher 5th, 1869. ) 



Wm. H. Butler, Esq., Chairman Department V: 



Dear Sir. — In response to your letter of the 1st instant, in respect 

 to the practical tests of steam engines, &c., entered for competition 

 at this exhibition, I would respectfully report as follows: 



It is desired by the exhibitors that the large steam engines be sub- 

 jected to thorough practical tests, and I believe this to be necessary 

 in order to enable the judges to act imderstandingly. 



In anticipation of such trials arrangements have already been made 

 whereby all the machinery in motion in the exhibition, may be driven 

 l)j either of the engines ; and the steam pipes are so arranged that 

 either of the engines can receive steam from either of the boilers, 

 without interfering with the working of the remaining engines from 

 the other boiler. There is not sufficient time to make a thoroughly 

 scientifie test, which shall include all the points that can possibly 

 arrise. We can, liowever, make some valuable practical trials suffi- 

 cient to determine if their be any important diiference in the engines 

 exhibited. I propose to compare the economy of the engines by the 

 weight of water evaporated into steam required to produce one net 

 horse-power. 



This may be ascertained by attaching a watermeter to one of the 

 boilers and dynamometers to the shafting. By this means the power 

 developed can be ascertained by inspection at any moment, and the 

 mean power established by numerous observations. Indicator dia- 

 grams may also be taken. The coal may also be M^eighed ; but this 

 plan is liable to inaccuracy, for the furnaces are large, and it will be 

 difficult to continue any experiment uninterruptedly, longer than 

 eight hours. I can have the use of the dynamometers and meter, by 

 simply paying for putting them up. 



The boilers should be tested by ascertaining the amount of %vater 

 evaporated per pound of coal ; but, as considerable water is lifted 

 with the steam of some of the boilers, it will be best to connect each 

 of the large boilers in turn, to the same engine, and ascertain the 

 water and fuel required to do the work. I do not consider that we 

 will have time to make also a practical trial of steam pumps. The 

 tests at the last exhibition were very thorough, and will, perhaps, 

 assist the judges at this time. The centrifugal pumps ought to be 



