42 
sulplinretted hydrogen and comparing the depth of colour 
produced with that in a standard liquid : the process is ex- 
ceedingly accurate and delicate. 
T/IBLE F. 
Copper dissolved hy ivater charged ivlth Carbon dioxide 
at ordinary pressure. 
Salt. 
Mgms. 
per 
Litre. 
Grains 
per 
Gallon. 
Copper dissolved. 
Mgms. per Lit 
24 ’ 48 1 72 
re. 
120 
Grains per Gallon. '' 
1 1 1 
24 1 48 72 ! hrs. 
Potassitim Carbonate.. 
i 
200 
14 
0-1 ... 
0-15 
0-2 ! 
1 
•007 ... 
•0105 -014 
Caicium Chloride 
200 ' 
i 14 
0-7 , ... 
1-20 
1-80| 
•049 ... 
•084| -126 
Ammonium Nitrate ... 
20 
! 1-4 
0-3 i ... 
0-601 
1-40 
1-021 ... 
•042 -098 
Ditto 
40 
' 2-8 
0-6 ... 
0-80 
1-40 
•042 ... 
•056; -098 
Potassium Carbonate 
j 100 
7 ] 
1 
1 
and 
) and 
1 and > 
0-2 ' ... 
0-30 
1-0 
•014 ... 
•02l| -07 
Ammonium Nitrate ... 
) 20 
j 1-4) 
1 
Potassium Carbonate 
j 200 
! 14 1 
1 
and 
’ and > 
trace . . . 
trace 
. 0-1 
trace ... 
trace' -007 
Ammonium Nitrate . . , 
) 40 
i 2-8) 
i 
1 Ammonium Nitrate 
j 20 
1-4 f 
i 
1 i 
j and 
1 and 
and > 
0-6 ... 
2-4 
3-0 
1-042 ... 
•168 -252 
i Calcium Chloride 
)200 
j 14 
j 
1 
i 
1 Distilled Water 
o 
O 
CO 
... 
1-0 
•007 -021 
... ; -07 1 
The general conclusions which I would draw from these 
results are : 
( 1 ) Distilled water, charged with carbon dioxide, exercises 
a notable solvent action upon copper, the amount of metal 
dissolved increasing with the length of time during which 
it is exposed to the action of the water, 
(2) The salts which have the greatest effect in increasing 
this action are chlorides and nitrates, especially the latter : 
if there are both present the action is very largely accelerated. 
(3) Carbonates, especially when present in large quanti- 
ties, very materially diminisli this solvent action. 
(4) If carbonates and nitrates are present together the 
solvent action of the latter is much diminished by the pre- 
sence of the former salts, so much so indeed that if the car- 
bonates be present in proportionately large quantities the 
solvent action upon the copper almost entirely disappears. 
I have also carried out a few experiments with the view 
