the Attractive Powers of Mineral Acids. Ccy 
The third point neceflary for the explanation of the pheno- 
mena attending the folution of metals, and their precipitation 
by each other, is to determine the proportion of phlogifton 
which they lofe by folution in each of the acids, and the affi- 
nity which their calces bear to the part fo loft. I have not 
been able to determine this by any direct experiment ; for 
though I might determine the part which efcapes in the form 
of air, yet I could not that which is equally feparated from the 
metal, but retained in the folution ; yet from various collateral 
conhderations I am induced to think, the proportion of phlo-' 
gifton, feparated from the metals by the different acids, is, at a 
medium, as exprelfed in the following table. 
By vitriolic acid 
Iron. 
Cop- 
per. 
Tin. 
Lead. 
Silver, 
Mer- 
cury. 
Z:uc. 
\V11- 
jnuch. 
Co- 
balt. 
ickcl K«i). ol 
jantimo. 
K.g. 01 
aifenc. 
2 
I 
8 
n 
1 
98 
Intirc 
8 7 
8; 
8 1 
9 3 
1 do 
Intire 
9 7 
86 
1 0 
1 O 
I 0 0 
too 
I O O 
IOO 
IOO 
1 0 0 
By nitrous acid 
I 
8 1 
7 
8 3 
Intirc 
9 
99 
9 7 
Intirc 
Intirc 
Intirc 
9 9 
IiO 0 
1 0 
IOC 
I O 
I OO 
i 0 0 
i 0 0 
By marine acid 
4 2 
5 7 
3 
6 
6 
7 
94 
8 
84 
8 
i O 
1 00 
1 O O 
I O 
I 0 
1 0 
1 0 
I OO 
J O 
I OO 
On this fuppolition the affinity of the calces to the deficient 
part of their phlogifton mayealily be calculated ; for they may 
be confidered as acids whole affinity to the deficient part of 
their bafis is as the ratio which that part bears to the whole, as 
already laid Thus the affinity of iron, thoroughly deprived 
of its phlogifton,. being 375, as it lofes qds of its phlogifton 
bv folution in the vitriolic acid, the affinity of iron to thefe two- 
thirds is ads of its whole affinity, that is, *ds of 375- 250. 
Tnefe affinities, together with thole of the three acids to 
the feveral calces, are reprefented together in the following- 
table. 
Vitriolic 
