Chemical Instruments and Operations. 261 



which consists of a volume of nitrogen, and two volumes of 

 oxygen, would require one volume of oxygen. Of course, if 

 nitrous acid be the product, one-third of the deficit produ- 

 ced, would be the quantity of atmospheric oxygen present. 

 This would be too much to correspond with the formula of 

 Gay-Lussac. 



Supposing hyponitrous acid produced, only one-half as 

 much oxygen would be required as is necessary to produce 

 nitrous acid ; so that instead of the two volumes of nitric ox- 

 ide taking one volume, they would take only a half volume. 

 The ratio of i in 21, is the same as 1 in 5, or one-fifth, which 

 is too little for Gay-Lussac's rule. 



The formula recommended by Dr. Thomson, agreeably to 

 which, one-third of the deficit is to be ascribed to oxygen 

 gas, is perfectly consistent with the theory of volumes, and 

 much more consonant to the results of my experiments than 

 that recommended by the celebrated author of that admira- 

 ble theory. 



The late Professor Dana ingeniously reconciled Gay-Lus- 

 sac's statement with the theory of volumes, by suggesting 

 that a half volume of oxygen may take one volume of the ni- 

 tric oxide, and another half volume of oxygen, two volumes. 

 Vol. Vol. 



I oxygen takes 1 oxide and forms ni- 

 trous acid. 



I oxygen 2 oxide and forms hy- 



ponitrous acid. 



to 



Deficit due to oxy- > ^ 



gen is as 5 



This result is evidently dependent upon the contingencies 

 which may prevent nitrous acid from being the predominant 

 product. I have accordingly found it precarious, in at least 

 one hundred experiments accurately made with the sliding 

 rod eudiometer. 



