.50 Mr. Herapath on True Temperature, and the [July, 



ammonia by chlorine ; the gas was successively passed through 

 . an acid and alkaline solution. 



The authors then give the results of their experiments, and 

 compare them with those of Biot and Arago, to which I have 

 added the determination of Dr. Thomson. 



Specific gravity of gases according to 



Berzelius and Dulong. Biot and Arago. Dr. Thomson . 



'■- Hydrogen . . 0-0688 0-07321 0-0694 



Oxygen.... 1-1026 1-10359 1-1111 



Azote 0-976 0-969 0-9722 



Garb. acid.. 1-524 1-519 1-5277 



According to these determinations, the atoms of the gases will 

 be represented as under : 



Berzelius and Dulong. Dr. Thomson. 



Hydrogen^ ...... 1-0 1 



Oxygen 8-013 8 



Azote 14-184 14 



Carbonic acid ... 22-151 22 



For the specific gravities of several other gases, we refer to 

 the original paper ; the experiments detailed in which appear 

 to have been conducted with great care. We may, however, 

 observe, that if any mixture of gases arising from the water 

 over which MM. Biot and Arago made their experiments, ren- 

 dered their hydrogen gas impure, and consequently heavier than 

 it ought to have been, the same cause would probably have 

 produced a similar effect upon the azotic gas. We find, how- 

 ever, that MM. Biot and Arago determine this gas to be lighter 

 •than it was found to be by the authors of this memoir in the pro- 

 portion of 0*969 to 0-976 ; and as Dr. Thomson more nearly 

 agrees with the former than the latter determination, we are 

 inclined to consider the specific gravitv of azotic gas to be nearer 

 0-969 than 0-976. 



Article IX. 



Tables of Temperature, and a Mathematical Development of the 

 Causes and Laws of the Phenomena which have been adduced 

 in Support of the Hypotheses of " Calorific Capacity, Latent 

 Heat," Sc. " By John Herapath, Esq. 



(To the Editor of the Annals of Philosophy.) 



DEAR SIR, CranforJ, Houmlow, London, June 18, 1821. 



The following tables of temperature exhibit a relation between 

 the true temperature, according to my theory of heat, and the 

 •degrees of Fahrenheit on the air thermometer, together with 



