and the Economy of Fuel. 119 



estimate the real loss of heat in each of the two ex- 

 periments before mentioned (No. 4 and No. 20), as also 

 in every other case in which the quantity of fuel con- 

 sumed, and the effects produced by the heat, are 

 known. 



Thus, for instance, in the 2Oth Experiment, as the 

 effects actually indicated that, with that part of the 

 heat generated in the combustion of i Ib. of the fuel 

 which entered the boiler, 2Oyo Ibs. of ice-cold water 

 might have been made to boil ; as by the above esti- 

 mate it appears that 31^5 Ibs. of ice-cold water might 

 be made to boil with all the heat generated in the com- 

 bustion of i Ib. of the fuel, it is evident that about one 

 third of the heat generated was lost, or ff^ of it was 

 saved. 



This loss is certainly not greater than might reason- 

 ably have been expected, especially when we consider 

 all the various causes which conspire in producing it; 

 and I doubt whether the economy of fuel will ever be 

 carried much farther. 



In the Experiment No. 4, as the effects produced by 

 the heat which entered the boiler indicated that no 

 more than 1.14 Ib. of ice-cold water could have been 

 made to boil with i Ib. of the fuel, it appears that in 

 this experiment only about ^th part of the heat gen- 

 erated was saved. 



In all the experiments made on a very large scale, 

 with brewhouse boilers, rather more than one half of 

 the heat generated found its way up the chimney, and 

 was lost. 



