270 Dr Fyfe on the Evaporative Power of Coal. 



ments I had them generally at the distance of about 8 inches. 

 The fuel was in general about 4 inches in depth, and in stok- 

 ing it was thrown as equally as possible over the whole sur- 

 face of the fire. 



It is unnecessary to state the result of the numerous trials 

 made after having satisfied myself that I had effected com- 

 pletely the combustion of the fuel. I will confine my remarks 

 to one only, performed when the furnace was in good work- 

 ing condition, the pressure on the boiler being 17 lb. It was 

 continued from ten in the morning till half after six in tbe 

 evening. Subjoined is a tabular view of the working, which 

 will shew the mode of proceeding, and the regularity with 

 which the fuel was supplied, and how the evaporation went on. 



In this trial the total quantity of coal used was 448 lb., and 

 the evaporation amounted to 3560 lb. ; there were therefore 

 evaporated 7.94 lb. for each pound of coal. The evaporative 

 power of this anthracite, when tried by the litharge test, was 

 found to be 10.78, compared to that of carbon as 12.3. 



Now 10.78-7.94 = 2.84,andl0.78 : 2.24: :100 :26.34; there 



