No perfon is better acquainted than our celebrated Prefident, 

 Vvith the many difficulties that occur in the analyfis of falts 

 in general ; particularly with regard to the quantity of real acid 

 they may contain. It has b.'en a work of trouble to the ableft 

 chymifts, and they have not always agreed in their refults. 

 r The proportions, announced by Fourcroy, may therefore be 

 doubted, in common with thofe of the other learned operators, 

 to whom I have alluded. 



The real quantity of acid, produced by the combuftion of 

 any acidifiable bafis, can be determined by one or other of the 

 following methods only : by dired combination, in fome fait, 

 the proportions of which are already known ; or by obtaining, 

 in a ftate perfedly free from water, the acid refulting from fuch 

 combuftion. To the former method, the general objedions 

 againft all analyfes of falts muft apply. The latter is ftill 

 more defedive'. It is by no means certain, that we have 

 ever yet obtained any acid, in a ftate of perfed ficcity, unlefs 

 we except the phofphoric and the arfenic ; for even the cryftal- 

 lized vegetable acids retain a portion of water in their cryftal- 

 lization. It is not that I abfolutely deny our having obtained 

 them fo ; but I fay merely, that we have no proof. It would 

 indeed be fetting narrow bounds to the perfedion of nature, 

 to affert, that no combuftible body could, when faturated with 



oxygen, 



