ENGINE TESTS. 



INTRODUCTION. 



THE first work in the line of engine-testing with which the 

 author was intimately connected was carried out at the Massa- 

 chusetts Institute of Technology in the years 1875 to 1878. 

 During this time he was engaged in conducting the experi- 

 ments of the late George B. Dixwell on the use of superheated 

 steam for motive power. . The experiments consisted princi- 

 pally in investigations on a Corliss engine operated with both 

 saturated and superheated steam ; and they embraced the deter- 

 mination of the performance of the engine running under both 

 of these conditions with different points of cut-off, and with 

 different degrees of superheating, together with the determina- 

 tion of the effect of other changes in the conditions of opera- 

 tion. The engine in question, and the testing apparatus 

 connected with it, formed the nucleus of a mechanical labora- 

 tory used in instructing the students of the Institute ; and it 

 was the first of the many steam laboratories which have been 

 established in the colleges of this country. In the course of 

 these investigations a board of experts, consisting of Chief 

 Engineers Loring, Baker, and Farmer of the United States 

 Navy, was appointed by the Bureau of Steam Engineering to 

 examine the subject; and they conducted a series of tests on 

 the same plant, and reported them to the Bureau. These trials 

 were under the active charge of the author. The character of 

 this work was such as to require from the very first the most 

 reliable apparatus and the best methods and instruments. In 

 preparing for it and carrying it on, the author had the best 



