S 8 + 
Mr. Keir’s Experiments, &c. 
,q I found alfo, that fiiver may be precipitated m its me- 
OlBc'tott. from its folu.ioi, in vitriolic sad. by addition or 
a rotation of martial vitriol. A vitriol of mercury may alfo 
be decompounded by a foliation of martial vitriol, and the mer- 
cmial precipitate, which is a black powder, forms globules, 
.when dried and warmed. • , • • , 
30 Luna cornea is not decompounded by martial vitriol ; 
■ confidently there is no operation of a double affinity. Never- 
thelefs, this luna cornea may be decompounded by the elemen s 
of martial vitriol, while they are in the aft of dilution , 
that is, the ffiver may be precipitated in its metallic a e, . y 
digefting luna cornea with a dilute vitriolic acid to which 
feme pieces of iron are added. And it is to be obferved, that 
this redudion of the ftlver and precipitation take place, while 
the acid is yet unfaturated. Marine acid and iron applied to 
luna cornea effed the fame redudion of the filver to a meta ic 
date, even when there is more acid than is fufficient for both 
The explanation of thefe phenomena will he attempted 
the fubfequent Papers which I propofe to prefent on this fub- 
jed to the Society. 
! 
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