iz NITROGEN. PARTI. 



having a capacity peculiar to itself, which under the 

 same circumstances is greater as its density is less; 

 therefore hydrogen the lightest of gases not only rises 

 in the air on account of its levity, but is more quickly 

 and completely diffused than oxygen which is the sup- 

 port of life. Though hydrogen is inferior in density 

 to every other gas, it surpasses them all in conducting 

 electricity, just as silver and copper conduct electricity 

 better than platinum, though far less dense. The great 

 refrigerating power of hydrogen is owing to its extreme 

 mobility and consequent rapid convection of heat, in 

 which it surpasses all other gases. It is as permeable 

 to radiant heat as atmospheric air, has a very high re- 

 fractive power, a specific heat of 3 '2936, and may be 

 substituted in many chemical formulse for a metal, 

 without altering their character : hence it is sometimes 

 called a metalloid. 



The quantity of nitrogen gas or azote that exists in 

 nature is enormous. It constitutes four-fifths of the 

 atmosphere, whence it may be had in a pure state, as 

 well as by chemical means. Like oxygen, this gas is 

 permanently elastic, without smell, taste, or colour ; it is 

 neither acid nor alkaline, it does not change vegetable 

 colours, it neither burns nor supports combustion, and 

 is incapable when breathed of supporting animal life. 

 It abounds in organic bodies, in all parts of the animal 

 texture, in the blood, muscles, nerves, even in the 

 brain; and is either a highly nutritious or poisonous 

 principle in the vegetable kingdom. 



Nitrogen gas is altogether passive ; it has no affinity 

 for the metals, and cannot be liberated from any of its 

 compounds even by electricity. Excepting boron and 

 titanium, it will not combine directly or spontaneously 

 with any simple element, even under the highest tem- 

 perature, but its indirect combinations are numerous 

 and violent : those with hydrogen are either noxious or 



