280 



Dr. H. F. Weber on the Specific Heat of 



in experiments performed with the object of determining the 

 exact temperature at which this point occurs. The steady de- 



A?/ 

 crease from 0° to 250° in the value of -remakes it almost certain 



AT 



that the'specific heat of graphite, as that of diamond, is expressed 

 by a constant number at higher temperatures. Inasmuch as it 

 appears that, in the curves expressing the specific heats of dia- 

 mond and of graphite, the value of the difference y T (graphite) 

 — y T (diamond) becomes smaller and smaller as T increases 

 (within the interval T= +50° to T = 250°) ; and as a series of 

 other elements exhibits the same specific heats in all their modi- 

 fications, it is probable that the constant values which express 

 the specific heats of diamond and graphite at high temperatures 

 are identical. 



A determination of the specific heat of graphite for the tempe- 

 ratures 500° to 1000° has completely fulfilled both of these ex- 

 pectations : the following Tables give the results of this deter- 

 mination. 



b. Experiments at High Temperatures with the double Calorimete?'. 

 Eighth Series. 





G. 



Q. 



At. 



W. 



AT. 



Ct -t. 



To- 



Platinum... 

 Graphite . . . 



Platinum... 

 Graphite... 



32-390 

 3-370 



32-390 

 3-368 



153-21 

 153-50 



15122 

 152-41 



3-920 

 3-820 



3-845 

 3-715 



600-5 

 586-3 



581-4 

 566-1 



535-2 

 519-2 



003465 

 0-3251 



003459 

 0-3237 



22-10 

 2200 



21-74 

 21-60 



From the first experiments ... W 22 - =1740. 

 From the second experiments W^?g 8 = 168-1. 



Ninth Series. 



Platinum... 

 Graphite . . . 



Platinum... 

 Graphite... 



32-390 

 3-260 



32-390 

 3-211 



153-44 

 154 03 



150-32 

 15104 



5 385 

 5-450 



5-367 

 5-315 



826-3 

 839-4 



8067 

 802-7 



720-2 

 705-0 



003541 

 0-3574 



003535 

 0-3549 



2238 

 22-45 



2212 

 2206 



From the first experiments ... \V^ 4 6 =257-5. 

 From the second experiments W 2 'of, =250 0. 



