PEEFAOE. 



This book relates to a large number of evaporative tests, 

 which were conducted personally by the author. The sub- 

 stance of Parts I and II, which form the body of the work, 

 was originally prepared at the request of the New England 

 Cotton Manufacturers' Association, and embodied in a paper, 

 which was read to that Society. A few copies of the paper 

 were reprinted from the Transactions of the Association, and 

 furnished to parties interested in the subject. The supply of 

 these was quickly exhausted. The favor with which the paper 

 was received, not only by members of the Association, but also 

 by those who have been supplied with the reprints, led to its 

 publication in the present form. In the revised work the ar- 

 rangement and numbering of the various boilers have been 

 changed, and cuts have been introduced to show the general 

 features of the boilers tested. An index has also been added. 

 These changes supply what was lacking in the paper as first 

 prepared, and give to the work that degree of completeness 

 which is desired in a book of reference. 



The book is offered to the public in the belief that it is 

 of considerable interest and value to steam engineers, manu- 

 facturers, and any persons who are concerned, either directly or 

 indirectly in the burning of coal and the economical genera- 

 tion of steam. 



GEO. H. BARRUS. 



95 MILK ST., BOSTON, 

 May, 1891. 



