166 PROCEEDINGS OF 



the distillation of sugar at 12.3 pounds, taking the water at 32°, which is equiva- 

 lent to 14.45 pounds, at the temperature of 212°. 



The experiments of Richardson and those of Regnault on eoals, and the analysis 

 of wood by Peterson and Shoedlen, have all had in view the determination by this 

 theoretical means of the heating power of the several combustibles. 



Ingenious as this method certainly is, it has failed to give results which could be, 

 generally, reproduced when a practical application was sought to be made of the 

 information thus acquired. The practical commonly fell short of the calculated 

 efficiency of fuel. 



In the practical determination of the value of fuel, the kind of evaporating vessel, 

 the due regulation of the fire, the nature and condition of the products of combus- 

 tion, the temperature of water used, and that of the air which supplies the grate, 

 are all circumstances to be attentively considered. The hygroraetin state of the 

 fuel itself also deserves notice. 



From the tables in the treatise above referred to, from page 129 to page 142, are 

 derived the following comparisons of results, deduced from the experiments of Dr. 

 Samuel L. Dana, of Lowell, Massachusetts. 



1. In plain Cylindrical Boilers, twenty feet long, thirty inches in diameter. 

 Sydney coarse bituminous coal, 7.18, 208 pounds per hour burned. 

 Philadelphia pea coal, 8.60, 180 pounds per hour, on an average. 

 Philadelphia pea coal, mean of 10 days running, 9.48, 100 pounds per hour burned. 



2. In Cylindrical Boilers, twenty feet long, forty-five inches in diameter. 

 Coarse Sydney anthracite, 6.04, 300 pounds burned per hour. 

 Anthracite dust i, Sydney slack i, 7.40, 233 pounds burned per hour. 

 Anthracite dust J, Sydney bituminous slack i, 7.51, 228J pounds burned per hour. 

 Best peach mountain anthracite, 8.00, 243 pounds burned per hour. 



Peach mountain anthracite, 8.43, 240J pounds burned per hour. 

 Beaver meadow anthracite, 8.89, 196 pounds burned per hour. 

 Coarse Lackawanna anthracite, 9.17, 249 pounds burned per hour. 



3. In three Cylindrical Boilers, thirty.six feet long, twenty. four inches in diameter. 

 Anthracite, coarse, 10.60, 179 pounds burned per hour. 

 Anthracite, coarse, 11.59, 151 pounds burned per hour. 



4. In four Cylindrical Boilers set on Mr. A. A. Hayes's plan, each twenty feet 

 long and twenty-four inches in diameter. 

 Sydney coal, screened from dust, 5.83, 250 pounds burned per hour. 

 Sydney slack alone, 8.64, 148§ pounds burned per hour. 

 Philadelphia pea coal alonp, 9.06, 117 pounds burned per hour. 

 Boston anthracite dust J, Sydney slack if, 9.60, lOti pounds burned per hour. 

 Lackawanna nut anthracite, 9.77, 106 pounds burned per hour. 

 Anthracite dust 3 parts, Sydney slack 1 part, 10.24, 141.5 pounds burned per hour. 

 Lackawanna egg, 10.28, 147.3 pounds burned per hour. 

 Anthracito dust \, Sydney ulnck i, 11.1.1, 112.5 pounds burned per hour. 

 Anthracilo dust J, Sydney slack \, 11.36, 67.1 pounds burned per hour. 

 Anthracite dust i, Sydney alack \, 11.37, 107 pounds burned per hour. 



