172 COUNT RUJNIFOED. 



water to its boiling-point, or through 180 Fahr. By 

 careful calculation he found this heat equal to that 

 given out by the combustion of 2303-8 grains ( = 4^ oz. 

 troy) of wax. He then determined the " celerity " with 

 which the heat was generated, summing up thus : 

 "From the results of these computations it appears 

 that the quantity of heat produced equably, or in a con- 

 tinuous stream, if I may use the expression, by the 

 friction of the blunt steel borer against the bottom of 

 the hollow metallic cylinder, was greater than that pro- 

 duced in the combustion of nine wax candles, each 

 three-quarters of an inch in diameter, all burning 

 together with clear bright flames." 



* " One horse," he continues, " would have been 

 equal to the work performed, though two were actually 

 employed. Heat may thus ba produced merely by the 

 strength of a horse, and in a case of necessity, this 

 heat might be used in cooking victuals. But no cir- 

 cumstances could be imagined in which this method of 

 procuring heat would be advantageous ; for more heat 

 might be obtained by using the fodder necessary for the 

 support of a horse as fuel." ' 



This is an extremely significant passage, intimating, 

 as it does, that Eumford saw clearly that the force of 

 animals was derived from the food, no creation of force 

 taking place in the animal body. 



' By meditating on the results of all these experi- 

 ments, we are naturally,' he says, ' brought to the great 

 question which has so often been the subject of specu- 

 lation among philosophers, namely, What is heat is 

 there any such thing as an igneous fluid? Is there 

 anything that, with propriety, can be called caloric ? ' 



' We have seen that a very considerable quantity of 

 heat may be excited by the friction of two metallic 

 surfaces, and given off in a constant stream or flux in 



