44 AGRICULTURAL CHEMISTRY 



inder unites with the carbon and hydrogen from the candle and 

 forms carbon dioxid and water. The CO 2 is soluble in water, 

 and the gas that is left is mainly nitrogen. The com- 

 bination of the oxygen with the carbon causes a partial vacuum 

 to form, and this results in the water rising in the cylinder. If 

 great care is taken in performing the experiment, it will be found 

 that the water will fill about one-fifth of the volume of the cylin- 

 der, occupying the space of the oxygen which has been com- 

 bined with carbon. When all of the oxygen in the cylinder is 

 combined with the carbon, the candle is extinguished because of 

 lack of oxygen for combustion. 



45. Properties of Nitrogen. In general, the physical 

 properties of nitrogen, except weight, are somewhat like 

 those of hydrogen and oxygen, inasmuch as when pure, 

 it is colorless, tasteless, and odorless. It is about 14 

 times as heavy as hydrogen, and only slightly soluble in 

 water. At a low temperature and under pressure, it is 

 liquefied, and at a still lower temperature and under higher 

 pressure, it is solidified. 



Chemically, nitrogen is unlike either hydrogen or oxy- 

 gen. It is an inactive gas; it is neither combustible nor 

 a supporter of combustion. When in the free state, it is 

 one of the most inactive of all the elements, and will com- 

 bine directly with only a few. When nitrogen enters into 

 combination with other elements, particularly with car- 

 bon and hydrogen, forming the organic compounds, it 

 has a tendency to make a weak link in the combination, 

 and will readily split off and form simpler products. In 

 the air, it serves the purpose of diluting the oxygen. No 

 other element could perform this function as well as ni- 

 trogen. If the air were composed of pure oxygen, all 

 combustion would be carried on in a rapid and wasteful 



