HG8 Absorption of nitrous gas: 



unlefs expofed to But if it be expofed to it, it rapidly abforbs oxigen, lofes its 

 abforbs'ox^cn '' c °l° ur > an( * becomes acid to the tafte. In this cafe, the green 

 becomes acid, oxide of iron is converted into red oxide ; and a fmall quantity 

 depofits red of ammonia is formed. 



oxide, and af- 

 fords a little When a folution of fulphate of iron, impregnated with ni- 



ammonia. trous gas, is placed under the receiver of an air pump, in pro- 



The impreg- portion as the prefliire of the atmofphere is removed from it, 

 nated folution, jt gives out its nitrous gas. When the mercury in the gage 

 its nitrous gas ftands at about -f^ of an inch, it becomes almoft wholly freed 

 without change, from it, recovers its colour, and is found unaltered in its pro- 

 perties. 

 The fame folu- When folutions of green fulphate, or muriate, of iron, im- 

 ernks nitrous pregnated with nitrous gas, are expofed to the heat of a fpirit 

 gas, depofits a lamp, nitrous gas is produced from them in a very pure ftate, 

 little red oxide, the fiuids lofe their dark co i our and a f ma ][ qua ntity of yellow 



and contains . . . 



ammonia. oxide of iron is thrown down in them. If examined after this 



procefs, they are found to contain a little ammoniac, combined 



with fome of the acid j and the oxide of iron diflblved is green 



oxide. 



Theory. The theory of thefe appearances is obvious. 



The nitrous gas The abforption of nitrous gas, by folutions containing oxide 



is firft abforbed of iron, at its minimum of oxidation, at common temperatures, 



by Ample afH- _ . . r . .... r 



nity j probably appears to be owing to a iimple combination between the gas 



from the attrac- and the fluid ; owing probably in fome meafure to the modi- 

 for oxigen. ' ^ cc ^ a ffi m ty °f tne g r een oxide of iron for oxigen ; for the red 



fulphate and muriate of iron have no affinity for nitrous gas. 

 Expofure to air The changes taking place in the impregnated folutions, 

 trous gas into" 1 " wnen expofed to the atmofphere, evidently depend upon the 

 acid ; a portion convertion of the nitrous gas of the folution into nitrous acid, 

 alfoof^he'wa- ^ v tne abforption of oxigen ; and upon the fubfequent decom- 

 ter, aredecom- pofition of a portion of this nitrous acid, and of the water of 

 pofed by the iron the roKxtion, by the green oxide of iron. 



converted into r 



red oxide. Heat feems to act. upon impregnated folutions, by increaf- 



Heat increafes ing the tendency of nitrous gas to aflume the elaftic form, and 

 the tendency of D y increaiing the affinity of the green oxide of iron for oxiVen. 



nitrous gas to fly J & J r •? a - «. .u 



off, and alio that * n coniequence, a portion of nitrous gas flies oft, and another 

 of the iron to portion is decompofed ; its oxigen combining with the green 

 and°witer! oxide, and its nitrogen with the hidrogen of a fmall quantity 



Hence red oxide of water, which is afted upon by a iimilar attraction. 

 oxi^Tof th y is the Thc abforption of nitrous g as b y Solution of common ful 

 gas and of the phate of iron was difcovered by- Dr. Prieftley. - It has been 



employed 



