OP ARTS AND SCIENCES: APRIL 11, 1871. olo 



The details of a complete analysis are as follows : — Having filled 

 the perfectly dry bottle, by means of a pair of bellows, with the air to 

 be analyzed, 50 c. c. of the baryta water are added, and the interior 

 surface of the bottle kept moistened by turning the same for about half 

 an hour. 



At the end of this time the baryta water is poured into a cylinder, 

 the latter tightly corked, and the carbonate of barium allowed to de- 

 posit, requiring about fifteen minutes. 25 c. c. of the nearly clear 

 liquid are now transferred to a small flask, and the oxalic acid solution 

 run in from a burette, until a single drop of the mixture fails to give 

 the alkaline reaction on turmeric paper. Taking, for example, the 

 first experiment made on the outer air, it was found that 20.4 c. c. of 

 the oxalic acid solution were required to neutralize 25 c. c. of the 

 baryta water after the action of the air. 



The difference between 20.4 c. c. and 23 c. c, the amount required 

 to neutralize 25 c. c. of baryta water before the action of the air, being 

 multiplied by 2, — for 50 c. c. of baryta water were used in the ex- 

 periment, — we obtain 5.2 c. c, each c. c. of which is equivalent to 

 nearly one mgrm. of carbonic acid, in accordance with the proportion : 



at.wt. at.wt. wt. of in 



O CO, 1 c. c. of sol. wt. of C0 2 . 

 63 : 22 — .0028636 : .0009998 



Multiplying this weight of carbonic acid by 5.2 c. c. and reducing the 

 product to volumes in terms of c. c. at the normal temperature and 

 pressure, we obtain 2.637 c. c. of carbonic acid in the volume of air 

 analyzed. Bottle No. 1 having been used, after reducing its volume 

 to the normal temp, and press., we obtain the percentage of carbonic 

 acid by a simple proportion, thus : — 



5783.26 : 2.637 = 100 : .04560%. 



In order to ascertain if the oxalic acid used in these experiments 

 could be depended on for purity, the strength of the baryta water was 

 tested with different solutions of the acid, prepared from crystals which 

 were obtained under various conditions. 



I. A solution of oxalic acid in hot water was made and allowed to 

 crystallize. These crystals were dried between sheets of blotting-paper, 

 2.8636 grms. weighed out, dissolved in water, and the solution made 

 up to a litre. 25 c. c. of the baryta water required 23 c. c. of this 

 solution. 



VOL. VIII. 40 



