a | 
tuitous, are grounded on the known properties of the agents 
employed, among which acids and falts are by far the moft 
univerfal; but to apply thefe with fecurity, their quantity, 
proportion and ftate, whether of concentration or dilution, 
fhould be afcertained with fome degree of accuracy ; this, how- 
ever, is allowed to be a problem of great difficulty, and few 
have attempted to folve it. Not aware of the obftacles it pre- 
fented, but fully fenfible of its importance, it has attracted my 
attention, and employed much of my leifure thefe ten years 
paft. My firft eflays are already known to the public; their 
defects and imperfections were fignified to me in the moft 
obliging manner by Meffrs. Morveau and Berthollet, men with 
whofe merit no part of Europe can be unacquainted. The 
methods I| have fince contrived to remove thefe imperfections, or 
at leaft to diminifh the aggregate of errors, form the fubject of 
this paper*. 
§ 1. Of the Proportion of Acid in the Mineral Acids. 
Of the Marine Acid. 
roo cubic inches of marine acid air weigh as nearly as I 
could eftimate 60 grs. barometer 29,6, thermometer 57°. 10 grs. 
of water abforb 10 of this air, bar. 29,6, ther. 49°. The fpirit 
of falt thus formed occupies the {pace of 13,3 grs. nearly; hence 
its 
* This paper was prefented laft April, and would have been read, had it not been that 
Mr. Pouget’s letter, on which much of this is grounded, had been miflaid. 
