158 COCNT RCftFORO's NE^T EXPERIMENTS 



the particle B, at the temperature of 167°, and on the other 

 the particle D, at that of 77°. The point in queftion is, whe- 

 ther the prefencc of thefe two particles will make any change 

 io the temperature of the particle C, or not. 

 •-of that middle In the firit place it is evident, that if the calorific influences 

 particle. Q f lJie p art j c i e J5 on the particle G be as efficacious in heating 



it, as the ftigoritic influences of the particle D be in cooling it # 

 the temperature of the particle C ought not to be changed. 

 But experience has (hewn, that, at equal diftances and equal 

 intervals of temperature> the calorific influences of hot bodies, 

 and the frigorific influences of cold bodies, are exactly equal; 

 and as thediftance from B to C is equal to the diftancefrom D 

 to C, while the interval of temperature between Band C = 

 45°, is the fame as that between D and C=45°; it is evident 

 that the temperature of the particle C, which is in the middle 

 of the cylinder, can be no way affected by the introduction 

 of the intermediate particles B and D. 

 And by the fame By the fame way of reafoning may be proved, that the in- 

 reaion it would troduction of an indefinite number of intermediate particles 



not be changed . \ 



by other pani- Would produce no change in the temperature of the middle of 

 des interpoftd. the axis of the cylinder, or in any part of it; and if the intro- 

 duction of an indefinite number of intermediate particles make 

 no change in the flate of a thermometer placed in the middle 

 of the axis of the cylinder, we may conclude that the ther- 

 mometer would remain equally ftationary> if the number of 

 intermediate particles were increafed till they had that proxi- 

 mity to each other which is neceflary to conftitute a folid body. 

 If, inftead of a iingle row of particles in a right line, there 

 were a bundle compofcd of an indefinite number of fuch rows 

 placed fide by fide, forming a folid cylinder, the temperature 

 in the different parts of the line A E would remain the fame. 

 But the tempf.r- From this reafoning we may infer, that the temperatures of 

 ature of a con- t j ]e differed par t s f the cylinder lliould decreafe in arithmeti- 



tinued folid ' J 



fhould decreafe cat progreffion from one extremity of the cylinder to the other, 

 from one parti- g ut j t j s evident, that this law of decrement of temperature 

 arithmetical pro- could take place only in the tingle cafe of the furfaee of the 

 grcflion. cylinder being completely ifolated, fo as to be no way affected 



onl^when 1 the ky the action of furrounding bodies, which is absolutely im- 



folid is remote poffible* 



from other yj^ c j rcum ft ance s under which the experiments were made 



Ourexperiments are very different from Ihofe here taken for granted. The 



arc always thus bodies 



influenced. 



