10 ENGINE TESTS. 



opportunity that could be afforded at that time for becoming 

 educated in the practice of engine-testing, and the training 

 thus acquired laid the foundation for much of the testing- work 

 in which he has since been engaged. 



This volume relates mainly to the engine tests which the 

 author has conducted subsequent to the investigations in super- 

 heating just referred to. It has been his custom, whenever en- 

 gaged upon any work relating to the performance of engines, 

 to advocate the determination of their economy on the basis of 

 feed-water consumption, rather than on that of the coal con- 

 sumed. Whenever called upon simply for indicating, he has 

 advocated the feed-water test, rather than to rely solely on the 

 showing of the diagram. In a great many instances the feed- 

 water test has thus been undertaken where it would have other- 

 wise been omitted. By following this practice, and answering 

 the calls which have come in the ordinary course, the ant Inn- 

 has personally obtained a considerable amount of data, which 

 he believes to be of value to the engineering public, as well as 

 to all who are interested in the use of power or development of 

 economical engines, and therefore worthy of puhlication in 

 permanent form, as here presented. 



The author's work in engine-testing has embraced the indi- 

 cating of engines for the simple purpose of valve-setting ; 

 indicating for the determination of the horse-power, or for 

 determining the power used by various machines or depart- 

 ments of machinery which the engine drives; investigations 

 upon the economy of different systems of operating engines ; 

 feed-water tests having for an object the improvement of the 

 engine and the attainment of greater economy ; and tests having 

 in view the determination of the fulfilment or non-fulfilment of 

 the terms of a contract guaranteeing a certain efficiency. These 

 investigations and tests have been made on a great variety of 

 engines, from the simple non-condensing engine with a single 

 cylinder, to the triple expansion condensing engine ; and they 

 relate to many designs and to products of many builders. Tlu-v 

 have also covered widely varying conditions of service as to 

 boiler pressure, cut-off, load, speed, and valve-setting, together 



