C 83 3 



Atmospherical Air, vr common Air. 



As the two gafes of oxygen and azote exift in 

 the air, merely in a ftate of intimate mixture, and 

 not in chemical combination, they may be eafily 

 feparated by a fubftance poffeffihg an ele&ric at- 

 traction for either of them : thus, if pure mercury 

 be expofed for fome time in clofed vefiels filled 

 with atmofpheric air, to a heat nearly approach- 

 ing to ebullition, a quantity of air will difappear, 

 and the mercury be converted into a red powder, 

 oxyd, or calx of mercury, which will have gained 

 an addition of weight equal to that of the air 

 abforbed, the mercury having united with the 

 pxygen gas, which leaves the azote. If a bell 

 glafs be inverted over a folution of liver of ful- 

 phur, the air in it will fufFer a diminution * fhe 

 oxygen will be abforbed, and the unabforbed part 

 will be azote, mowing that there are 27 parts of 

 oxygen, and 73 parts of azote in 100 parts of at- 

 mofpheric air. 



If the azote in liver of fulphur be expelled, 

 and the oxygen in the red calx of mercury, or 



elaftic fluid. Oxygenated muriatic Acid gas % or dephlogifikated ma-> 

 tine acid, which is difengaged during the reciprocal aclio'n of 

 native oxyd of mangauele and muriatic acid, being produced 

 by the tranfition of oxygen from the manganefe into the muria- 

 tic acid. Ammoniac gas, alcaline air, or volatile alcaline gas, is 

 difengaged by heat from liquid ammoniac ; or, from a mixture 

 of ammoniacal muriate, or common fal ammoniac, with quick 

 lime. Hepatic gas, or folphurated hydrogenous £as, is obtained 

 from folid alcaline fulphures, or livers of fulphur, by decompof- 

 ing them with acids. Phofphorated hydrogenous gas, or ph ifphork 

 gas, obtained by boiling a lixivium of cauftic pot-afh with half 

 its weight of phbfphorus, and receiving the elaitic fluid difen- 

 gaged into giafles containing mercury. 



M 1 precipitate 



