114 On the Powers of Steam, &fc. 



That no deception might arise, from the bottom of 

 one of the basons being thicker than the other, or 

 from one part of the stove, on which they stood, be- 

 ing hotter than the other, I now repeated the experi- 

 ment, changing the basons, and the places on which 

 they were set. In four minutes, the bason heated 

 by steam rose to 80, the other one being only at 45. 

 In seven minutes, they were at 94 and 54 ; and in 

 nine minutes, the difference was 102 and 63. 



From these experiments, the powers of steam in 

 communicating heat appear very evident ; and it 

 seems probable, that these powers might be applica- 

 ble to some useful purposes in the arts. Dr. Black 

 (as was before observed) has shown, that solid bodies, 

 in passing into a state of fluidity, absorb a large quan- 

 tity of heat from substances with which they are in 

 contact ; hence it follows, that if this liquifaction can 

 be produced by any other means than external heat, 

 these contiguous substances will be robbed of their 

 heat, which is powerfully absorbed by the liquifying 

 body. Upon this principle, he explains the artificial 

 cold produced by the solution of salts, and by the 

 common freezing mixtures. He has also shown, that 

 fluids, in passing into a state of vapour, absorb a fur- 

 ther quantity of heat from contiguous bodies. 



Upon this principle depends the fall of a thermo- 

 meter, dipped in water, and then exposed to the wind; 

 the method of cooling bottles of water, on the coast 

 of Coromandel, by exposing them in a wet cloth, and 

 hanging them up, exposed to the hot land wind, 



