Prof. Regnault on the Specific Heat of some Simple Bodies. Ill 



I made some determinations with another specimen of rho- 

 dium, also lent by M. Chapuis ; it was a medal, remarkable for 

 its sharpness, and had been struck at the Paris Mint. The medal 

 was suspended during the experiment by a very fine silk thread, 

 the influence of which might be neglected : — 



M . 



. . 47s r -107 



47s r -107 



T . 



. . 96°*77 



97°-75 



& . 



. . ll°-07 



9°-80 



A6' . 



. . l°-5498 



P-6791 



A . 



. . 149^-576 



149^*73 



C . 



. . 0-05742 



005865 



Mean . . . 0-05803 



The product of the specific heat 0*05803 by the equivalent 

 652*1 is 37-84. 



Iridium, 



I have made several determinations of the specific heat of iri- 

 dium at different times on specimens which 1 have succeeded in 

 procuring. In 1839 I worked upon a very large piece of conso- 

 lidated iridium which had been lent by M. Meyendorff. I found 

 (Ann. de Chim. et de Phys. 2nd series, vol. lxxiii. p. 53) for the 

 specific heat 0-03683 ; this number, multiplied by the equivalent 

 1233-2, gives 45**43. In 1855 (Ann. de Chim. et dePhys. 3rd series, 

 vol. xlvi. p. 263) M. Chapuis lent me another quantity of iridium 

 which formed half a disc, strongly compacted by percussion ; I 

 found for this specimen the number 0*0363, which is little dif- 

 ferent from that obtained with M. MeyendorfPs specimen. Never- 

 theless, as the product 45 of the specific heat by the atomic 

 weight is very high, I always considered the metal impure, and 

 sought opportunities of making fresh determinations. In 1857 

 M. Chapuis offered me a new specimen, also consolidated by per- 

 cussion, and which he considered purer than that of 1855 ; this 

 specimen gave me the following results : — 



M . . . 300^-55 300^-55 



p . . . 1^-5048 1^-5048 



T . . . 97°-63 97°-50 



& . . 



A0' . . 



A . . 



C . . 



Mean . . . 004186. 

 This specific heat is still higher than that which I found for 

 the preceding specimens, and, multiplied by the atomic weight, 

 gives the number 51*62. 



20°*71 



21°-34 



2°-3284 



2°-2923 



466sr-69 



466^-69 



0-04200 



0-04173 



