CHANGES PRODUCED IN AIR BY RESPIRATION. JgJ 



- The apparatus consists of three gasometers, two of which Apparatus for 

 are filled with mercury, a»id one with distilled water. purport. 



The water gasometer which belongs to the Royal Institu- 

 tion is capable of holding four thousand two hundred cubic 

 inches of gas, and each of the mercurial ones three hundred 

 cubic inches; the apparatus was so arranged, that the inspi- 

 rations were all made from the water gasometer, and the ex- 

 pirations into the mercurial gasometers alternately. Each of 

 the gasometers is furnished with a graduated scale, and they 

 aire all made to range with each other, so that the quantity 

 of gas inspired and expired could be immediately and ex- 

 actly ascertained: to each of tlua mercurial gasometers a 

 glass tube is fixed, aud made to euter a mercurial bath, from 

 which portions of the expired air could at any time be taken 

 for examination. 



By the kindness of our friend Silvanus Bevan, we are 

 enabled to give an accurate drawing of the apparatus. 



Description, 



PI. VI, fig. 1. The communication with the water gaso- Referenced 

 meter. the plat*. 



2. A cock so constructed that it might be made to com- 

 municate with either of the mercurial gasometers, while at 

 the same time all connexion with the other was cutoff. 



A. The mouth piece. 



3 to 10. Brass cocks. 



G. I, and G. 2. Mercurial gasometers. 



S. S. Scales graduated to cubic inches. 



M, Mercurial bath. 

 The large reservoir or water gasometer is not shown in 

 this drawing, it having been so frequently described in che- 

 mical works. 



Manner of conducting the Experiment. 



Qur first care was, to be certain that all the parts of our Mannerof con- 

 apparatus were perfectly air-tight, and this, from the nature experin/nts 

 of it, was very easily ascertained ; we agreed, that the breath- 

 ing should always be performed by one of us, and the regis- 

 tering &c. by the other, as each would by these means ac- 

 quire 



