Analysis of the Human Breath. 119 



Table XIII. 



Teiasion of gas, in Absorption per 100 by 



parts of an inch. carbonic acid and dry air. 



0-5 32*1 



10 48-3 



1-05 48-8* 



11 49-4 



1-15 50-0* 



1-2 50-7 



1-25 51-3* 



1-3 52-0 



1-35 52-3* 



1-4 52-6 



1-45 530* 



1-5 53-4 



1-55 53-7* 



1-6 ..... 54-0 



1-65 54-3* 



1-7 54-5 



1-75 54*9* 



1-8 55-2* 



1-9 55-9* 



2-0 565 



Referring to the absorption by 30 inches of breath in bag 

 No. II. given in Table V. and found to be 52*8 per cent., we next 

 compare this absorption with the nearest approach to it seen in 

 the above Table ; this is at 1 *4 of an inch tension • this amount 

 of carbonic acid, when mixed with 20 inches of dry air, absorbs 

 52*6 per cent, of the entire radiation from a carbonic oxide name. 

 We may therefore conclude that the absorption by 30 inches of 

 breath in this case is approximately the same as by 1*4 inch of 

 carbonic acid ; from which we obtain 4" 66 as the percentage of 

 carbonic acid in the breath of bag No. II. Let us now turn to 

 the analysis made by Dr. Frankland of the same breath. In 

 Table VI. we find he states this expired air to contain 4*556 of 

 carbonic acid. Our determination is therefore a remarkably 

 close approximation, considering the novelty of this analysis by 

 physical means, and the difficulties attending these first experi- 

 ments. 



A number of other specimens of breath taken at different 

 periods were examined ; their absorption and the percentage of 

 carbonic acid are given in the following Table. Dr. Frankland 



* The absorptions thus marked have been intercalated. 



