INTRODUCTION. 11 



with various conditions in regard to quality of steam, use of 

 jackets, and the tightness of valves and pistons. 



The tests reported in this volume have not been made with 

 an organized attempt to obtain the performance of certain types 

 and makes of engines ; but they are the result of the investiga- 

 tions which the author has made in responding to the calls of 

 his clients, whether it hap[>ened to be for one object or another, 

 and whatever the class of engine or conditions of service. So 

 far as given here they are confined mainly to stationary engines 

 located in manufacturing establishments, and in most cases 

 operating Avith a fairly uniform load. Nearly all the tests apply 

 to engines which have a capacity of at least 100 horse-power, 

 and they run from this size up to 1700 horse-power. 



The first part of the volume is devoted to Feed-Water Tests, 

 taking up first the simple engine, both condensing and non- 

 condensing, and afterwards compound, and triple-expansion 

 engines. The results of the test on each engine are given in a 

 table by itself, and they are presented in such detail that all 

 necessary in formation regarding the subject is at hand. In 

 connection with the results is given in each case the dimensions 

 and such information regarding the design of the engine, the 

 cniid it inns under which it was worked, and the character of the 

 test, as is needed for a clear understanding of each case ; and 

 comments on the results are added where these are required. 

 In all the engines the condition of the valves and pistons as to 

 leakage is pointed out so far as this can be expressed in general 

 terms. The engines selected were, as a rule, fairly tight; but 

 in a few cases tests of leaking engines are introduced, either on 

 account of the general interest attaching to them, or to show 

 the wasteful effect of the leakage itself in some special instance. 

 The tables of feed-water tests are followed by a chapter which 

 presents a general review of the results, showing in brief the 

 main points of information which the tests bring out. This 

 chapter takes up the question of cylinder condensation, and 

 analyzes the tests here reported, with the object of determining 

 what the percentage of cylinder condensation under different 

 conditions of running practically amounts to. The relative 



