182 CHANGES PRODUCED IN AIR BY RESPIRATION, 



quire a greater degree of dexterity in performing his part, 

 and the results would be more uniform. 

 Experiment. The water gasometer being filled with common air to a 

 certain mark upon the scale, and the mercurial ones com- 

 pletely empty, the person to breathe, whom we shall uni- 

 formly call the operator, was seated upon a stool, with his 

 mouth e,ven with the tube A, his nose being secured with 

 a steel clip. He made as complete an expiration as possible 

 into the open air, then applying his lips to the tube, and 

 keeping his left hand constantly on the cock 1, and his right 

 hand on the cock 2, he opened the communication with the 

 water gasometer, and made an inspiration; then immedi- 

 ately closing it, he opened with his right hand the cock at 

 2; and that at 4 being also opened, he expired into the mer- 

 curial 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 gasometer; 

 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 off: 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 expelled. 

 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 

 tha 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 experi- 

 ments. 



No. 



