42 
sulphuretted hydrogen and comparing the depth of colour 
produced with that in a standard liquid : the process is ex- 
ceedingly accurate and delicate. 
T/4BLE F. 
Copper dissolved by water charged with Carbon dioxide 
at ordinary pressure. 
Mgms. 
per 
Litre. 
Copper dissolved. 
A. 
1 
Salt. 
i 
Gram."? { 
per Mgms. p< 
Gallon. 
j 24 48 
jr Litre. | 
72 ! 120 
Grains per Gallon. ' 
i 120 1 
24 1 48 72 i hrs. 
Potassium Carbonate . . 
200 
14 0-1 ... 
0-15 
0-2 
•007 ... 
•0105 *014 
Calcium Chloride 
200 
14 ! 07 ... 
1*20! 
1-80 
•049 ... 
•084 *126 
Ammonium Nitrate ... 
20 
1*4 0'3 ... 
0-60 
1*40 
•021 ... 
•042 -098! 
Ditto 
40 
2-8 0*G ... 
0-80 
1*40 
•042 ... 
’056 -098! 
Potassium Carbonate 
1 100 
! 7 ) 
I 
1 
and 
> and 
and > 0'2 ... 
0-30 
1-0 
•014 . 
•021 -07 
Ammonium Nitrate ... 
) 20 
1 1*4) 
! 
Potassium Carbonate 
j 200 
14 ) 
and 
} and 
and > trace ... 
trace 
o-i 
trace . . . 
trace ‘007 
Ammonium Nitrate ... 
) 40 
2*8 ) 
Ammonium Nitrate 
| 20 
D4 , 
1 
and 
? and 
and > 0'6 ... 
2-4 
3*6 
1*042 ... 
•168 ’252 
Calcium Chloride 
) 200 
14 ) 
1 
Distilled Water 
i 0-1 0*3 
1 
... 
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 
