COMBINATIONS OF OXYGEN AND NITROGEN. 41 



made to disappear ; the water acquires a sweetish 

 taste, but its other properties do not differ per- 

 ceptibly from common water. The whole gas 

 may be expelled again by heat. 



It does not change blue vegetable colours. It 

 has a sweet taste, and a faint, but agreeable odour. 



This gas explodes with hydrogen, when electric 

 sparks are made to pass through the mixture. 

 Animals, when confined wholly in this gas, give 

 no signs of uneasiness at first; but they soon be- 

 come restless, and then die. 



When it is mingled with atmospheric air, and 

 then received into the lungs, it generates highly 

 pleasurable sensations. The effects it produces on 

 the animal system are very extraordinary ; it ex- 

 cites the body to action, and rouses the faculties of 

 the mind, inducing a state of great exhilaration, 

 an irresistible propensity to laughter, a rapid flow 

 of ideas, and unusual vigour and fitness for muscu- 

 lar exertions, in some respects resembling the sen- 

 sations attendant on intoxication, without any lan- 

 guor or depression of spirits, or disagreeable 

 feelings afterwards ; but more generally followed 

 by vigour and a disposition to exertion, which 

 gradually subsides. 



This gas is produced when substances having a 

 strong affinity with oxygen are added to nitric acid, 

 or to nitrous gas. It may, therefore, be obtained by 

 various methods, in which nitrous gas or nitric acid 

 is decomposed by bodies capable of attracting the 

 greater part of their oxygen. The most commo- 

 dious and expeditious, as well as cheapest mode 

 of obtaining it, is by decomposing nitrate of ammo- 

 nia by heat, in the following manner: put into a 

 glass retort some pure nitrate, and apply to it 

 an Argand's lamp ^ the salt will soon liquify, and 



