53 J Cendu fling Peweif of Bodies with Regard to Meat, 



new compound B. Compound C is a third time formed by ftratum i. Three (Irata 

 are now heated. Stratum I is combined with three dofes, ftratum 2 with two dofes, 

 ftratum 3 with one dofe. The heat can pafs no farther, for ftratum 4 cannot decompofc 

 compound A, nor compound A compound B, nor compound B compound C ; but ftra- 

 tum I combines with a fourth dofe of caloric, and forms a new compound, which we 

 fliall call D. This Hew compound is decompofed by ftratum 2, which forms compound 

 C. Stratum 2 Vs decompofed by ftratum 3, which forms compound B, and ftratum 3 by 

 ftratum 4, which forms compound A. Stratum i again forms compound D, which is 

 again decompofed by ftratum 2. This, in its turn, is decompofed by ftratum 3, which 

 forms compound B. Stratum i again forms compound D, which is again decompofed by 

 ftratum 2, in order to form compound C. Compound D is again formed by ftratum r, 

 and is not now decompofed. Here are four ftrata combined with caloric. Stratum i with 

 four dofes, ftratum 2 with three dofes, ftratum 3 with two dofes, and ftratum 4 with one 

 dofe. In this manner may the heating progrefs go on till any number of ftrata whatever 

 are combined with caloric. 



Thus we fee that caloric is conducted through bodies merely by repeated chemical com- 

 binations and decompofitions. Hence the reafon of the flownefs of its progrefs. We 

 fee, too, that the temperature of the ftrata muft diminifli in a kind of arithmetical ratio 

 according to their diftance from the fource of caloric ; and this, in fa£l, holds in every 

 inftance. When one end of an iron rod is held in the fire, the temperature gradually 

 diminifhes as we approach the other extremity. Wc fee, too, that the diftance to which 

 a body can conduft caloric muft in all cafes depend upon the degree of heat to which 

 the firft ftratum of its particles can be fubje£led, before it changes its ftate. If it can 

 bear a very great heat, the body will condudl to a very confiderable diftance ; whereas, if 

 if it can bear but little heat, the body will conduft but a very fhort way. Thus brick will 

 condud much farther than wood, becaufe when the temperature is raifed above a certain 

 degree, the wood catches fire, and is diflipated; whereas, the brick undergoes no change. 

 The diftance, then, to which a body conducts caloric, is not a criterion of the goodnefs of 

 its conducing power, fo much as of the degree of heat to which it can be fubjeded 

 without a change of ftate, unlefs the heat be far inferior to what is capable of producing 

 fuch a change. It appears, too, from this account, that the conducting power of a body 

 isj in all cafes, Inverfely as its affinity for caloric. Confequently, the beft condudtors arc 

 thofe bodies which have the weakeft affinity for caloric. 



It can fcarcely be doubted that caloric is conduced through all folid bodies in the min, 

 Jier above defcribed. AH folid bodies hitherto examined are conduftors of caloric. Fluids, 

 too,, were univerfally confidered as condudors, till Count Rumford drew the contrary 

 conclufion from his very ingenious experiments. If his conclufions be juft, this con- 

 ftitutes a very curious and important diftindion between folid and fluid bodies. But the 

 more important the conclufion is, the more rigidly ought we to examine the premifes 

 before we adopt it.. 



3' Count 



