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



Ay 

 True specific heats of the diamond y T Values of — m- 



WO'O _w°"° 



■79-7 -21'2 = 00fi35 



= 0955 



V— 50 - 5 



58-5 



y-io-6 



w°'° 



_ VV — 2P2 



21-2 





o-o 



yio-7 



214 



^33-4 



W 45'35 w 214 



vv o-o ~ w o-o 



23-95 



^58-3 



W 7l-2 w 4535 

 _ v Vo W 0'0 



25 85 



3^85-5 



W 99-8 W 71'2 



_ v Vo — w o-o 



286 



y,,„ «. 



_ w 80 " 2 -wf 8 



^140-0 



80-4 



^206-1 



, 17 .232-0 w 180'2 

 W ~ W 



51-8 



?/o^. n 



_ wf^-wf 2,0 



= 01128 



01318 



= 01532 



=01765 



= 0-2218 



50 



0-2733 



3026 



0030802 from -50° to -10< 



0000812 from -10° to 10°. 

 000837 from 10° to 30°. 

 0000859 from 30° to 60°. 



0000856 from 60° to 85°. 

 000083 1 from 85° to 140°. 

 0000779 from 140° to 205°. 

 0000716 from 205° to 250°, 



From these experiments it appears that the specific heat of dia- 

 mond increases uninterruptedly as the temperature increases 



Ay 

 from —50° to + 250°, — the velocity of this increase, -^L slowly 



accelerating from -50° to +60°, and from +60° to +250° 



constantly diminishing. In the neighbourhood of + 60° there 



is a turning-point in the curve representing the specific heat of 



diamond. The constant diminution, from 60° upwards, of the 



Ay 

 value -r>p makes it probable that this diminution will continue 



to increase at higher temperatures, and that there exists a tem- 



Ay 

 perature at which -~ becomes exceedingly small, or even dis- 

 appears entirely — and, further, that there is a definite limit of 

 value towards which, as the temperature rises, the specific heat 

 tends. To test the truth of this expectation, the specific heat of 

 the diamond was determined for three temperatures between 

 500° and 1000° by the aid of the double calorimeter already de- 

 scribed. The crystals used in the foregoing experiments could 

 not now be made use of, as at the high temperatures employed 



