14 
DR. W. MARCET OR A CHEMICAL INQUIRY INTO 
Found Carbonic Acid as expired per minute. 
Gramme. 
0-3905 1 
0-3881 / 
0-4581 1 
0-4571 / 
0-4228 1 
0-42O3 / 
0-5108 1 
0-5087 j 
0-4403 1 
(•-4393 j 
0-402.5 I 
0-4052 J 
0-4O15 1 
0-4007 / 
0-3030 1 
O-3041 / 
0-4203 I 
0-4-243 / 
0 434S I 
0-4345 / 
0-4246 1 
0-4234 / 
0-4011 1 
0 4000 / 
0-4033 1 
0-4040 / 
0-3760 1 
0-3758 / 
Means . 
Dilference, 
0-0024 
0-0010 
0-0015 
0-0021 
0-0019 
0-0027 
0-0008 
0-0011 
0-0020 
0-0003 
0-0012 
0-0005 
0-0013 
0-0008 
. 0-0013 
Per cent. 
= 0-61 
= 0-22 
= 0-35 
= 0-41 
= 0-25 
= 0-58 
= 0-20 
= 0-30 
= 0-47 
= 0-07 
= 0-28 
= 0-12 
= 0-32 
= 0-21 
= 0-31 
The following precautions were taken in these analyses as necessary to ensure 
absolutely correct results by Pettenkofeu’s method :— 
1. The distilled water used for diluting the solution of barium hydrate (100 to 
200 C.C.), was thoroughly boiled, and kept in glass stoppered Winchester quarts. 
Before using this water it was carefully tested and rejected if one drop of the dilute 
alkaline solution (25 c.c. normal barium solution in 100 c.c. aq.) failed to show a 
reaction in about 30 c.c. of the distilled water coloured with two or three drops of 
solution of turmeric. 
2. The same burette was used in every experiment, and every titration was 
commenced at 0 of the burette scale, the burette being always refilled. 
3. The air drawn into the burette by displacement of the fluid was filtered through 
a tube containing pumice stone moistened with a saturated solution of potassium 
hydrate in very dilute glycerine, and connected wdtli the burette by a cork and india- 
rubber tubing. Thus none of the atmospheric carbonic acid could reach the solution 
in the burette. 
4. During the titration air blown from a bellows over pumice stone, moistened with 
potassium hydrate in dilute glycerine, was driven through the wide-mouth bottle in 
which the titration was being made, so that atmospheric carbonic acid never came in 
