102 4 VKAR IX SCIENCE 



absorbed by water. For this purpose phosphorus 

 is most generally used. After filling the pneumatic 

 trough with water to the depth of two inches, float 

 a small piece of cork on it. Place on the cork 

 with forceps a piece of yellow phosphorus about 

 the size of a small pea. After igniting the phosphorus, 

 quickly invert a belljar over it so as to confine a 

 portion of the air. The phosphorus will burn as long 

 as there is any oxygen in the jar, forming a white 

 cloud of solid particles, oxide of phosphorus. During 

 the next twenty or thirty minutes this cloudy oxide 

 will be absorbed by the water, and the gas remaining 

 in the jar is nitrogen. 



Nitrogen may also be prepared by taking a mixture 

 of 8 grams of sodium nitrite and 3 grams of ammon- 

 ium chloride, to which is added about 15 c.c. of water 

 heated gently below the boiling point of water. In the 

 chemical action resulting between these compounds, 

 nitrogen is liberated, which may be collected as were 

 oxygen and hydrogen. 



Properties. Nitrogen is a colorless, odorless, tasteless 

 gas. That it is very inactive may be seen by insert- 

 ing a burning splinter into a bottle of the gas. The 

 flame is extinguished at once. Nitrogen neither burns 

 nor supports combustion. Because of its inactivity it 

 is only with the greatest difficulty that it can be made 

 to unite directly with any substance. 



Uses. The very great inactivity of nitrogen might 

 lead one to think it of little use in nature. It is in 



