39 



and Inserted into the mould in the midst of the 

 growing peas. The lime-water soon acquired a pel- 

 licle on its surface, which, by the fourth day, was 

 very thick, and, by the sixth day, had sunk down 

 to the bottom of the glass ; and the water into 

 which the jar was inverted, had risen in it to a con- 

 siderable height, proving that carbonic acid was 

 formed, and that a diminution in the bulk of air 

 had taken place. 



31. As the mould, in which these plants grew ? 

 might by some be supposed to influence the produc- 

 tion of the carbonic acid, the experiment was next 

 varied in the manner following. Some mustard 

 seeds, which were raised on moistened flannel, and 

 had grown to more than an inch in height, were in- 

 troduced into a jar of atmospheric ai , and supported 

 about half way up it by a small whalebone hoop, 

 covered with netting. In a deep dish, filled with 

 water, and appointed to receive the inverted jar, was 

 placed a glass of lime-water, which stood directly 

 under the hoop. In four hours, a thickish pellicle 

 overspread the lime-water, and the inside of the jar 

 was bedewed with moisture. At the end of twenty- 

 four hours, the lime-water was very turbid, and the 

 water, into which the jar was inverted, had risen near- 

 ly half an inch. These appearances increased du- 

 ring the two succeeding days, at which time the 

 water stood nearly an inch high in the jar. The 

 plants now began to look sickly, gradually drooped, 

 and, by the ninth day, fell down in different direc- 

 tions against the sides of the jar, and, when with- 

 drawn from it, emitted a putrid smell. The resi- 

 dual air extinguished a taper, rendered lime-water 



C 4 



