332 Dr. T. Andrews on the Heat disoigagcd during the 



Stdphiir and Oxi/gen. 



The sulphur was employed in the state of flowers ofsulphur 

 deprived of tlie acid with which they are always contaminated 

 by washing. A small quantity of earthy residuum remained, 

 the weight of which was determined at the end of each expe- 

 riment, and deducted from the original weight of the sulphur. 

 During the combustion, a small quantity of sulphuric acid 

 (corresponding to about 3 per cent, of the sulphur) was formed, 

 lor which reason the experimental results must indicate a little 

 more than the true quantity of heat due to the conversion of 

 sulphur into sulphurous acid. The heat in these experiments 

 was given out in the course of eight minutes. 



1. 2. .3. 4. 



M 3-087 gnns. 3*089 grms. 3*240 grms. 3-114 grms. 



T 10°-4 ]2°-8 8"-0 8°-7 



E 1^-0 1^-0 l°-5 0°-9 



I 2°-510 2°'436 2°'467 2H61 



Ic 2-'512 2°-438 2°-476 2°-462 



W 2699 grms. 2739 grms. 2818 grms. 2737 grms. 



V 175 grms. 175 grms. 175 grms. 175 grms. 



1. 2. 3. 4. 



2338 2300 2287 2302 



We have, therefore, for the heat evolved during the com- 

 bination of — 



One gramme sulphur with oxygen . 2307 

 One gramme oxygen with sulphur . 2307 

 One litre oxygen with sulphur . . 3315 



Dulong's experiments indicate from 2452 to 2719 units of 

 heat for each gramme ofsulphur burned. 



graphite, but differs from tlieir experiments with wood-charcoal itself. 

 Furtlier researches are required to settle this difficult question. At present 

 I will only venture to direct attention to the apparently anomalous circum- 

 stanceinFabre and Silbeiniann's results, that while wood-charcoal extricates 

 so much more heat in combining with oxygen than graphite or the diamond, 

 the- two hitter yield very nearly the same quantity of heat. 'J1ie analogy 

 of the specific heats of these three forms of carbon is at variance with such 

 a result, as will immediately appear from the following comparison : — 



Specific heat Heat of combination 



(Regnault). (Fabre and Silbermann). 



Diamond 0-147 78^24 



Graphite 0-201 7778 



Wood-charcoal 0-242 8080 



'I'hus, while wood-charcoal has both a higher specific heat, and gives more 

 heat of combination than graphite, the latter, with a higher specific heat, 

 produces less heat of combination than the diamond. 



