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XX. Experiments and Obfervations on the Diffblution of Metals 
m Acids , and their Precipitations ; with an Account of a new 
compound acid MenJiruum , ufeful in fame technical Operations 
of parting Metals . By James Keir, Efq. F. R . S. 
Read May 20, 1790. 
I N the following Paper, I intend to relate two fets of experi- 
ments ; one 9 fliewing the effects of compounding the vitriolic 
and nitrous acids in dijfolving metals ; and the other, defcribing 
fome curious appearances which occur in the precipitation of 
fiver from itsfolution in nitrous acid by iron 9 and by fome other 
fubfances. In a fubfequent Paper I hope to continue the fubjedt 
of metallic diffolution * and precipitation, firft, by adding fome 
experiments on the quantities and kinds of gas produced by 
diflolving different metals in different acids, under various cir- 
cumftances ; fecondly, by fubmitting certain general propoft ions , 
* The Englifh word folution has two fignifications in chemifiry ; one, expref- 
live of the aft of diffolving, as when we fay, that “ folution is a chemical 
operation and the other, denoting the fubfiance diffolved in its folvent, as 
** a folution of filver in nitrous acid.” The French language is equally equi- 
vocal, as the word “ diffolution” is ufed in both the above-mentioned fenfes. In 
treating on this fubjeft, in which both meanings were very frequently required, 
fometimes in the fame fentence, I could not but be fenfible of confufion in the 
flyle, and X have therefore confined the word folution to exprefs the fubftance 
diffolved together with its folvent, and the word diffolution to denote the ad of 
diffolving. 
which 
