52 THE FOOD OF PLANTS CHAP. 



ing into the jar is closed by the brass disk attached to 

 the wire handle of the spoon. The phosphorus in burn- 

 ing gives off a copious white smoke, which presently 

 collects into flakes, which fall like snow to the 

 bottom of the bell-jar and collect on the glass plate. 

 When the phosphorus has gone out, remove the 

 deflagrating spoon and test the air left in the bell- 

 jar with a lighted taper. The taper goes out, show- 

 ing that the air has again been altered by the burn- 

 ing body. Lift off the bell-jar and the glass plate 

 is seen to be covered with a white snow-like powder. 

 During this experiment the phosphorus has dis- 

 appeared and this white powder has been formed, 

 which contains the phosphorus. It, however, must 

 contain something else besides phosphorus, as on 

 weighing it, it is found to weigh more than the phos- 

 phorus which was consumed. (This cannot be shown 

 without special arrangements.) Apparently, then, 

 the phosphorus in burning is joining with, or 

 combining with, some other body, which is 

 obtained from the air by which it is sur- 

 rounded ; and it is on account of the absence 

 of this body that nothing will burn in the 

 bell-jar afterwards. 



The Phosphorus removes Part of the Air 



We can now proceed to vary this experiment, so 

 as to decide definitely whether any part of the air 



