342 



SCIENTIFIC RECREATIONS. 



We must be careful how we handle phosphorus, for it has a habit, well 

 known, but sometimes forgotten by amateur chemists, of suddenly taking 

 fire. Light this piece of phosphorus, a small piece will do if the jar be 

 of average " shade " size, and place the glass over it, as in the illustration 

 (fig. 325). The smoke will quickly spread in the jar, and the entry of air 

 being prevented, because the jar is resting under water, phosphoric acid will 

 be formed, and the oxygen thereby consumed. The water, meanwhile, will 

 rise in the jar, the pressure of the air being removed. The burning 

 phosphorus will, soon go out, and when the glass is cool, you will be 

 able to ascertain what is inside the jar. Put a lighted taper underneath, 

 and it will go out. The taper would not go out before the phosphorus 

 was burnt in the glass, and so now we perceive we have azote in the 



324. Rutherford's experiment. 



receptacle that is, nitrogen. The other, the constituent of our atmosphere, 

 carbonic acid, as we have seen, is very injurious to the life of animals, and 

 as every animal breathes it out into the air, what becomes of it ? Where 

 does all this enormous volume of carbonic acid, the quantities of this poison 

 which are daily and nightly exhaled, where do they all go to ? We may- 

 be sure nature has provided for the safe disposal of it all. Not only 

 because we live and move about still, and of course that is a proof, but 

 because nature always has a compensating law. Remember nothing is 

 wasted ; not even the refuse, poisonous air we get rid of from our lungs. 

 Where does it go ? 



It goes to nourish the plants and trees and vegetables that we delight 

 to look upon and to eat the fruit of. Thus the vegetable world forms a 

 link between the animals and the minerals. Vegetables obtain food, so to 



