COUNT RUHFORD. 167 



ments were probably prompted by his views on mole- 

 cular physics. He would hardly have thought of the 

 foregoing arrangement were not the intestine motions 

 of the ultimate particles of bodies present to his mind. 

 He was, moreover, quite aware of the importance of the 

 result here established. The subject had often occupied 

 his thoughts, and he had at different times made ' a 

 considerable number of experiments with a view oi 

 throwing light into the profound darkness with which 

 the subject is shrouded on every side.' 



He devoted his attention to steam, considered as a 

 vehicle for transporting heat ; he sought for the means 

 of increasing the heat obtained from fuel ; he devised 

 a new steam-boiler, in which we have a forecast of 

 the tubular boiler of George Stephenson. After some 

 preliminary experiments on wood and charcoal, he 

 definitely took up the important investigation of the 

 quantity of heat developed in combustion, and in the 

 condensation of vapours. He described the new calori- 

 meter employed in the inquiry. It was a kind of worm 

 through which the heated air and products of combus 

 tion were led, and in which the heat was delivered up 

 to cold water surrounding the worm. 



He experimented upon white wax, spirit of wine, 

 alcohol, sulphuric ether, naphtha, charcoal, wood, and 

 inflammable gases. Whenever it was possible he aimed 

 at quantitative results, and in the present instance he 

 ' estimated the calorific power of a body by the number 

 of parts by weight, of water, which one part by weight 

 of the body would, on perfect combustion, raise one 

 degree in temperature. Thus 1 Ib. of charcoal, in com- 

 bining with 2f Ibs. of oxygen, to form carbonic acid, 

 evolves heat sufficient to raise the temperature of about 

 8,000 Ibs. of water 1 C. Similarly, 1 Ib. of hydrogen, 

 in combining with 8 Ibs. of oxygen, to form water, 



