366 THE CHEMISTRY OF CREATION. 



some ; for it is said, the plants vitiate the air.* 

 It is important to set the real state of this 

 beautiful case of nature's chemistry before the 

 reader, if only to assist him to a right know- 

 ledge of facts. To ascertain the point, the fol- 

 lowing experiment may be suggested to those 

 who are sufficiently expert in mechanical and 

 chemical manipulation to attempt it. Take any 

 plant, the branches of which are sufficiently 

 long and well-clothed with leaves (see cut), and 

 insert it in a dish of mercury, bringing it up 

 through the fluid into an inverted glass jar filled 

 with air containing a slight excess of carbonic 

 acid.f The apparatus may be easily arranged, 

 as in the cut, and the whole must be exposed 

 to sun-light. If now, in a few days' time, the 

 air in the jar is examined, by merely intro- 

 ducing a lighted taper into it, it will be found 

 that the flame is much more brilliant than in 

 open air, which is due to the presence of an 

 increased amount of oxygen in the air of the 

 jar. From this we learn, and the experiments 

 of Boussingault, Saussure, and Priestley, have 

 with due accuracy proved the fact, that plants 

 in reality, while exposed to the sun, retain the 



* Plants with a profusion of flowers undoubtedly vitiate the 

 air, to some slight extent, until the flowering season is over. 



f Easily produced by pouring a little dilute hydrochloric acid 

 over a lump of chalk or marble, and then allowing the gas to 

 escape into a jar, out of which it may be poured into this jar. 



