and Oxygen Gas by Respiration. 245 



right hand on the coek, fig. 2, he opened the communication 

 with the water gasometer, and made an inspiration ; then 

 immediately closing it, he opened with his right hand the 

 cock at 2 ; and that at 4 being also opened, he expired into 

 the mercurial gasometer G. 1.; then closing 2, which cut 

 off all communication with the mercurial gasometer, he 

 opened 1, in order to make a fresh inspiration ; then closing 

 it, he again opened 2, and expired into the mercurial gaso- 

 meter ; and proceeding in this way, always taking care to. shut 

 one cock before the other was opened, the air was made to 

 pass from the water gasometer, through the lungs of the 

 operator into the mercurial gasometer, and this with great 

 ease, as the diameters of the tubes were purposely made large. 

 The scale of the mercurial gasometer was carefully noticed, 

 and when nearly full, the cock 4 underneath was shut ofT; 

 then, by a signal from the operator, his colleague opened 3, 

 and the expirations were received in G. 2. While this was 

 filling, the number of cubic inches in G. 1 was registered^ a 

 portion saved in the mercurial bath, and the rest quickly ex- 

 pelled. This operation was repeated until the contents of 

 about twelve or thirteen mercurial gasometers were taken 

 off: the operator always concluding with a strong effort to 

 empty his lungs as completely as possible. The quantity 

 inspired from the water gasometer was then compared with 

 the quantities expired into the mercurial gasometers, and the 

 difference noted. The following are the results of the first 

 ten experiments. 



Cubic inches Cubic inches 

 No. Time. of common air of gas Deficiency. 



inspired. expired. 



1. timenotnoted 3760 3741 19 



2. 11 minutes 3900 3869 31 



3. 10-i- ■ 3624 3620 4 



4. 10£ 35 70 3551) 20 



5. 11 3685 3653 32 



6. 11 3380 3355 25 



7. 10^ 3180 3141 39 



• 8. 10J- 3360 329S 62 



Q, lox 32QO 3267 23 



10. 11 3580 3543 3/ 



In this last experiment we ascertained that the expired gas 

 contained 8 per ce»t. of carbonic acid, 



Q 3 The 



