INTRODUCTION. H 



The tests are so varied in object, in conditions, and in type 

 of boiler, that it has proved advisable to take up each boiler 

 and the tests made upon it, separately, and give, as briefly as a 

 clear presentation of the subject warrants, the general features 

 and dimensions of the boiler, the data and results of the tests, 

 and memoranda of the main points of information which the 

 tests reveal. Given in this form, the reader will find means 

 for studying the subject, if desired, from his own standpoint. 

 The special object of the paper is an examination of the tests 

 as a whole, and a classification of the data and results, so as to 

 put in connected shape the information which they give as to 

 the conditions which govern the economical generation of steam 

 and the best practice in boiler engineering. 



The paper is divided into two parts ; Part First embracing the 

 analysis of the tests as a whole, and Part Second treating of 

 the various boilers, and the tests made upon them individually. 



Before entering upon the proposed examination, the general 

 subject of boiler tests and the methods which were employed 

 in conducting the tests under consideration demand attention. 



The object of all boiler tests, first sought, is the determina- 

 tion of the weight of water evaporated by a pound of coal. 

 The object ultimately sought varies in different cases. Some 

 tests have in view the determination of the efficiency of the 

 boiler as a generator of steam, when operated under such con- 

 ditions of quality of fuel, kind of firing, capacity and general 

 management as will give the best result. These determine the 

 true efficiency of the generator. Others have in view the gen- 

 eral result produced by the boiler, however much it is affected 

 by disturbing causes, and they determine the economy with 

 which the fuel is burned, whether the type of boiler, kind of 

 fuel, capacity, mode of firing and management are favorable or 

 unfavorable. 



Owing to the two general objects named, boiler tests might 

 be divided to advantage into two classes. The first might be 

 termed the engineering test, being of greatest interest to the 

 engineer, who must know the true efficiency of the boiler to 

 intelligently lay out his plans. The second might be termed 



