1821.] Mr. Phillips's Reply to Dr. Hope. 25 



tained should lose so large a proportion of deutoxide of azote as 

 2-25 parts out of 15, instead of only about 1-2, as by my ex- 

 periment; and I conclude that the 15 parts of nitrous acid 

 •which you obtained consisted very nearly of 



Nitric acid, sp. 1495 13-8 



Deutoxide of azote 1*2 



15-0 

 Instead of 



Nitric acid, sp. 1500 12-75 



Deutoxide of azote 2*25 



15-00 



Which must have been its composition, had you procured it 

 from 24 parts of nitre, by the action of 16 parts of the strongest 

 sulphuric acid. 



You will perceive that, making an allowance in your fa- 

 vour, the sulphuric acid contained only 3*2 of water, and it 

 could not condense more than 9*55 of nitric acid. I conclude, 

 therefore, either that the sulphuric acid which you employed 

 could not be of the strength directed in your Pharmacopoeia, or 

 that you have made some error in your statement. 



It is evident, from what I have just stated, that I have been 

 able to procure nitrous acid of specific gravity 1522 ; and here I 

 must acknowledge that 1 was not aware that nitrous acid could 

 be obtained of a " full red " colour, without employing impure 

 nitre, or without using some means to convey the gaseous pro- 

 ducts arising from the decomposition of nitric acid through the 

 acid distilled. I repeat that 1 was not aware that by mere expo- 

 sure to the gaseous products, the nitric acid first distilled would 

 absorb sufficient deutoxide of azote, to be in any considerable 

 degree converted into red nitrous acid. By continuing the appli- 

 cation of heat, however, for a great length of time, I procured 

 red nitrous acid, of specific gravity 1534 ; but the quantity 

 which I obtained convinced me that, as I have already endea- 

 voured to show, your statement must be incorrect, or that you 

 employed sulphuric acid differing in strength from what is 

 directed. Twelve ounces of nitrate of potash and eight ounces 

 of sulphuric acid, of specific gravity 18-475, were put into a 

 retort, and heat applied until acid ceased to distil. The product 

 was of specific gravity 1534, it weighed six ounces six dr. ; show- 

 ing that 24 parts would yield only 13-6 parts instead of 15, when 

 acted upon by 16 parts of sulphuric acid, and of these 13-6, the 

 water must have constituted 3-2 parts ; nitric acid, 9'5 , and the 

 remaining 0-9 part will be accounted for by the loss of deutoxide 

 of azote, as already noticed. 



