284 



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



mond are identical for every value of the temperature T, and 

 representing the amounts of heat given up by 1 grm. of graphite 

 and 1 grm. of diamond when cooled from T x , T 2 , &c. to T 

 (where T lf T 2 , &c. >T ) by the series 



and 



WT1-T0 



W 



To-T 





wJ>- T °, w?- T °, WJ- T », 



the following equations hold good :• 



WT»- T »-WJ J - T »= Wj>- T °-Wj " T ». 



w? 



The following experiments prove that these equations may be 

 accepted as expressing actual facts. 



3*3 grms. of graphite were placed in one of the platinum ves- 

 sels already described, and 3*5 grms. of diamond in the other. 

 When these were heated to the same temperature they were 

 brought into the double calorimeter and allowed there to cool. 



First Experiment. 

 Heated to about 550°. 





G. 



Q. 



At. 



W. 



T . 



Graphite...... 



Diamond ... 



"3-380 



3-512 



12310 

 125-81 



4-278 

 4150 



526-6 

 522-2 



21-42 

 21-33 



Second Experiment. 

 Heated to about 750°. 



Graphite 



Diamond . . . 



3-362 

 3-525 



151-11 

 15340 



5-224 

 5172 



789-4 

 793-5 



21-63 

 21-58 



Third Experiment. 

 Heated to about 1000°. 



Graphite 



Diamond . . . 



3-401 

 3-541 



203 22 

 20313 



5-607 

 5-658 



1139-5 

 1149 3 



21-30 

 24-41 



The amounts of heat given up by 1 grm. of graphite and 1 

 grm. of diamond respectively in cooling from about 550°, 750°, 

 and 1000° to about 21°-5 were therefore 



Graphite. 



Diamond 



158-14 . 



. . 148-72 



234-82 . ■ 



. . 225-11 



33505 . . 



. . 324-56 



