Cti PUTREFACTION, 51 



Humboldt, but not found to differ from atmospheric air in the 

 proportion i f its oxygen and nitrogen. 



The stale of the barometer, however, Was not attended to in 

 this experiment, which renders it liable to exception. Neither 

 did Dr. Priestley attend to the state of the barometer in his 

 experiments, or if he did he omitted to*mention it. 



I repeated this experiment over mercury. The thermometer Repetition of 



as before stood at 70, and the barometer at 20- 1 inches. The rhe "P en ' 

 ' ^ ment over 



experiment was continued three days, when the putrefactive mercury ; with 

 fermentation had taken place, as was evinced by the odour n0 absorption, 

 emitted: but there was at no time any absorption of mercury 

 within the jar. Upon examining the included air with the 

 eudiometer it was not found to ditfer from atmospheric air. 



But to magnify and render more conspicuous any absorption, The same re- 

 in consequence of a diminution of the included atmospheric ^ different 1 

 air, by the combination of its oxygen with the animal matter, I mercurial ap- 

 invented an instrument which I shall now describe. paratus, 



I took a cylindrical bottle perfectly transparent, and put half 

 a pound of muscular flesh (a portion of the diaphram of a 

 bullock) in the bottom of it and secured it there. The flesh 

 was taken while warm, and cooled under mercury to prevent the 

 access of air. To the bottle was adapted a cork which was per- 

 forated, and a bent tube passed through the perforation, the 

 other end of which was hermetically sealed. Some mercury 

 was then put into the bottle — the bottle corked and made 

 perfectly air-tight by luting and sealing — the bottle was now 

 inverted. The mercury filled about two inches of the neck of 

 the bottle, and was made to pass up the glass tube by heating 

 it, and expanding the air, and thus expelling a portion of it to > 



a proper distance. In this situation the bottle was put to rest 

 in a fixed position. A thermometer was included within the 

 bottle in order to note the temperature. 



The bottle and curved tube in some measure represented 

 Mr. Leslie's Differential thermometer. The barometrical 

 influence was perfectly excluded. And as variations in the 

 temperature equally affected both the air included in the tube, 

 and that in the bottle, it is evident that thermometrical influence 

 could not affect the experiment. To the tube was adapted a 

 graduated scale, which would mark any rise or fall of mercury 

 in the tube. 



E 2 Now 



