50 



C H F, M I S T R Y. 



Kinneiiu phosphorus, and acquire* the property of burning 

 ' ' with a yellow flame. 



_*-*! .?' The simple incombuctibles have no effect on it at 

 any temperature tried. Chlorine gradually destroy* 

 a over water, convertuig it into carbonic acid gas. 

 This mixture cannot be kindled by electricity ; 

 whereas a mixture of chlorine and carbureted hydro- 

 gen burn directly when an electric spark is passed 

 through them. 



Its action on metals and their oxides has been but 

 imperfectly examined. Neither the alkalies nor the 

 earths have any action on it whatever. 



Oiidetof 

 azote. 



Nitrous 

 oxide gas. 



How ob- 

 tained. 



It proper 

 tin. 



SECT. 111. Of the Oxides qfAsote. 



Azote and oxygen form two different oxides, both 

 gases, and both discovered by Dr Priestley. The 

 first has been called nitrous acid gas, the second ni- 

 trous gas, or nitric oxide gas. 



1. Nitrons O.ride Gas. 



This gas was discovered by Dr Priestley in 1 TTG, 

 and called by him depMogislicalfd nitrous gas. The 

 associated Dutch chemists examined it in 1793, and 

 ascertained its composition. But for the best ac- 

 count of it, we are indebted to Mr Davy. 



It may be obtained by exposing the salt called wi- 

 tnite of ammonia, in a retort to a heat between 34-0 

 and 500 a . It melts and emits abundance of gas, 

 which may be collected in jars of water. 



Thus obtained, it has all the mechanical properties 

 of air. Its specific gravity is 1.G03, that of air be- 

 ing 1.000. 



It supports combustion better than common air, 

 almost as well as oxygen gas, but for a much shorter 

 time. But combustibles do not burn in it, unless 

 previously in a state of ignition. 



It may be breathed for a short time, and produces 

 effects similar to intoxication. 



Water absorb* nearly its own bulk of this gas, and 

 acquires a sweetish taste ; but its other properties are 

 not perceptibly altered. It may be driven off from 

 the water unaltered by means of heat. 



It is not altered by light, nor by a moderate heat. 

 But by a red heat it is decomposed, and converted 

 into nitric acid and common air. 



Oxygen, or common air, has no action on this gas. 



Sulphur, if introduced into this gas while burning 

 with a blue flame, is immediately extinguished ; but, 

 if it be burning with a violet flame, it continues to 

 burn for some time with great brilliancy with a fine 

 red flame. The products are sulphuric acid and 

 azote. 



Phosphorus, when touched with a wire white hot, 

 burns with great brilliancy in this gas. The pro- 

 ducts are azotic gas, phosphoric acid, and nitric acid. 



Charcoal may be kindled in it by means of a burn- 

 ing glass. The products are carbonic acid gas, and 

 azotic gas. 



Hydrogen detonates with it by means of electrici- 

 ty. According to Mr Davy, 39 measures of nitrous 

 oxide consume 40 measures of hydrogen, and after 

 the combustion 41 measures of azotic gas remain. 

 From this experiment it has been concluded, that 

 nitrous oxide is composed by weight of 



63 azote. 

 37 oxygen. 



_ ^__ 



100 



Elements 



tt 

 utiy. 



Sulphureted, phosphureted, and carbureted hydro- Compoii- 

 gen gas likewise burn when mixed wiia nitrous oxide, tiun. 

 and kindled. 



Neither azote nor muriatic acid produce any effect 

 upon this gas. 



Some of the metals, as iron and zinc, burn or may- 

 be oxidized in it. 



It has the property of combining with alkalies, 

 and of forming a peculiar species ot salt, to which 

 the name of azutiles may be given. Mr Davy, to 

 whom we are indebted for the discovery of these 

 compounds, did not succeed in combining nitrous 

 oxide with ammonia and the earths but he has ren- 

 dered it probable that such compounds are possible 1 . 



2. Nitrout Gas. 



This gas was accidentally obtained by Dr Hales ; Nitrous 

 but its properties were first investigated, and its na- g^ 

 ture ascertained, by Dr Priestley. 



To obtain it, dissolve copper or silver in nitric HOW ot* 

 acid diluted with water, a gas separates, which may tained. 

 be collected in jars over water, and is the gas in ques- 

 tion. 



It possesses the mechanical properties of common '' proper- 

 air. Its specific gravity is 1.091, that of air being " 

 1.000. 



It is exceedingly noxious to animals, producing 

 instant suffocation whenever they attempt to breathe 

 it. 



Most combustible substances refuse to burn in it. 

 But pyrophorus burns in it with great splendour ; and 

 Homberg's phosphorus takes fire in it spontaneously, 

 just as in common air. Dr Henry has ascertained, 

 that ammoniacal gas, when mixed with it, detonates 

 by means of electricity. 



When mixed with common air, or oxygen gas, a 

 yellow colour appears ; and if the mixture be stand- 

 ing over water, its bulk gradually diminishes very 

 considerably. The yellow colour is owing to the 

 presence of nitrous acid which is formed, and the di- 

 minution of bulk to the gradual absorption of that 

 acid by the water. The cause of this remarkable 

 phenomenon is obvious. The nitrous gas combines 

 with the oxygen, and forms nitrous acid. Hence 

 the diminution of bulk depends upon the quantity of 

 oxygen present. There is a good deal of difference 

 in the result obtained by chemists of the amount of 

 the diminution of bulk which ensues. According to 

 Dalton, 21 measures of oxygen gas unite either with 

 36 measures of nitrous gas, or with 72 measures. 

 According to Gay-Lussac, 100 measures of oxygen 

 gas unite either with 200 or with 300 measures of 

 nitrous gas, according to circumstances. 



Nitrous gas, by electricity, is converted into ni- 

 trous acid and azote. 



Water, according to Dr Priestley, absorbs about 

 one-tenth its bulk of this gas ; according to Dr Hen- 

 ry, about one-twentieth ot its bulk. 



It is decomposed by phosphorus and charcoal, and 

 probably also by sxilphur at a very high temperature. 

 Hydrogen gas mixed with it burns with a green 



