vi THE COMPOSITION OF THE AIR 51 



We have yet to learn, however, if the whole or 

 only part of the air is consumed in this change as it 

 passes through the burning charcoal. 



The Action of burning Phosphorus on the Air 



In order to decide this point we shall try some 

 experiments with another substance which burns 

 readily, and which is used in the manufacture of 

 matches, namely, phosphorus. 



Experiment 31 



Phosphorus is sold in sticks which are always 

 kept under water, owing to their tendency to go on 

 fire when exposed to the air. Take one of these 

 sticks out of the bottle by means of a pair of nippers 

 or a sharp-pointed penknife, and, placing it under 

 water in a saucer, scrape it clean at one end with 

 the knife, and cut off a little piece, about a quarter 

 of an inch thick, and cut it into four bits. Re- 

 move one of these bits with the nippers and dab 

 it gently with blotting-paper to dry it, then place it 

 in a deflagrating spoon. Take the bell-jar used in 

 the last experiment and dry it thoroughly inside and 

 place it on a sheet of window glass carefully dried and 

 remove the stopper from the jar. Light the phos- 

 phorus in the deflagrating spoon by touching it with 

 a hot wire, and lower it into the bell-jar till the open- 



