2T4 Examination of the received DoBrmes 



perceiving any fuch effect." It may be true that a thick ball 

 of frmll capacity will not give any fcnfib'e indication of heat 

 to a hand applied to it, or even to a fluggifh thermometer, 

 which can only touch it in one point ; for, where a large 

 mafs of materials is ready to receive the heat as it is expreffed 

 from the air, the effect may not be immediately obvious: it 

 would be a lono- time before a large piece of ordnance could 

 be made feniibly hotter by applying the flame of a taper to it, 

 but who would therefore deny that heat has paffed into the 

 metal ? Inilead of applying their hands to the condenfing 

 ball, let them, as before ftated, place a thermometer in the 

 ftream of the air when liberated, and they may receive com- 

 plete evidence that the air demands a portion of caloric to 

 brino- it into equilibrium with the furrounding bodies, which 

 could not poffibly be the cafe if it had not previoufly fuffered 

 fome privation. 



I (hall here briefly ftate the refults of an experiment under- 

 taken for the exprefs purpofe of afcertaining whether there 

 liad been any miftake in the facts reported by others refpee~t- 

 ing the phenomena which accompany the compreffion of 

 air *, 



By means of a powerful fyringe A, Plate VI. fig. I. 

 (2?, inches long and 2 infide diameter) made faft to one end 

 of a table and to the floor of the room, the veflel B, con- 

 structed of tinned copper, and made faft to the other end of 

 the table, was charged with as much air as could be forced 

 into it by the llrength of one man. The temperature of the 

 room was 59°. Bv the condenfation of the air, the thermo- 

 meter C, introduced into a tube foldered into the veffel B 

 (and open at its exterior extremity), was raifed feven de- 

 grees. On expofmg the bulb of another thermometer to 

 the orifice of the cock D, which was then opened to dif- 



* For the execution of this experiment I am indebted to the London 

 Phifofbphical Society. Having ftated to that Society the fact, which I 

 wifheri to fee afcertained, the fubjeft was taken up with that alacrity and 

 teal which chara&erifes all its proceedings. The apparatus was prepared 

 bv Mr. Varley, experimenter to that inttitution, and the experiment was 

 wade in the prefence of the Society on the 18th of November 1799. 



charge 



