on Cooking for the Poor. 539 



tity would have required (upon the above supposition) to 

 heat it from the temperature of 55° to that of 212° a 

 quantity of heat equal to that which would be gene- 

 rated in the combustion of 100000 °^ ^ pound of the 

 wood in question. 



But it appears, by the result of experiments published 

 by Dr. Crawford, that the quantities of heat required to 

 heat any number of degrees, the same given quantity 

 (in weight) of water and of wheat (and it is presumed 

 that the specific or absolute heat of rye cannot be very 

 different from that of wheat), are to each other as 

 2y^o to I ; water requiring more heat to heat it than the 

 grain in that proportion. Consequently, the quantity 

 of wood required to heat from 55° to 212° the iiVo Ih. 

 of rye-meal which enters into the composition of each 

 loaf instead of being lowoo o^ a pound, as above de- 

 termined, upon the false supposition that the specific 

 heat of water and of rye were the same, would, in fact, 

 amount to no more than if If io , for 2-1^0 (the specific 

 heat of water) is to i (the specific heat of rye) as looooD" 



lb lU 1 00 0- 



Hence it appears that the wood required as fuel to 

 heat (from the temperature of 55° to that of 212°) a loaf 

 of rye-bread (in the state of dough), weighing 2I lbs. 

 would be ,as follows : namely, — 



0£ pine-wood, 

 lb. 



the composition of the dough To oof o" 



To heat the rye-meal, i-jVir lb. in weight . . ^%^^ 



Tntal 7 3 3 5, 



To complete the computation of the quantity of fuel 

 necessary in the process of baking bread, it remains to 

 determine how much heat is required, to send off in 



