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Henck ihe proportion ofjixed air in aerated vol-alkalis is to that of 

 mere alkali in thofe falts as \'^ to 6, and the remainder is water 

 of compofition. 



Wenzel, p. loo, alfo perceived that the proportion of mere 

 alkali in aerated vol-alkali was very fmall, and ftates it nearly as 

 low as I do; for to 240 grains of this fait, containing 53,75 per 

 cent, of fixed air he afcribes 139 of fixed air, 31,125 of water, and 

 confequently 79,875 of mere alkali. Hence 100 grains fhould 

 contain 53,75 fixed air, 33,28 of alkali and 12,97 of water. 



Common Sal Ammoniac. 



By diftilling in a pneumatic apparatus and a fand heat, 100 grains 

 of fublimed fal ammoniac and 300 grains of quick lime, I found 

 it to yield as much alkaline air as amounted to 25 grains, with 

 fome few drops of water; the remainder of the water being pro- 

 bably detained by the lime or by the muriated lime which is known 

 to retain water moft obflinately. 



By treating 100 parts of this fait in folution with a folution of 

 nitrated filver, I found it to afford 258,5 of muriated filver heated 

 to fufion, and confequently to contain 42,75 of real marine acid. 



Hence 



1 



