Keib VulUcntkm, 273 



*^^ Thi>: gas is obtained by fxpofiiig the miinatic acid tp 

 heat and evaporation while it is a6lihg on a fabihnce that 

 'contains oxvgen ; fuch, for examplej af5 the tialive oxyd of 

 hiangancfe. If you therefore put 50 parts of the liativeoiyd 

 ^fmanganefe arid 160 parts of muriatic acid into a glafs re- 

 tort^ and t'xpofc it to heat, il ftrohg feriiien ration will be ex- , 

 fcited, during whith the muriatic acid will be coilvertcd into 

 gas, but furchargcd with oxygen which it takes from tjie 

 bxyd of manganefe, becaufe it has a great afiinity for that 

 fubllance. To collecl ibis gas, when »'ou have reafon to 

 think that all the air in the retort has palled over, introduce 

 the beak of it below a bell filled with mercury or water; for 

 this gas dt)es riot diOblve in watfer biit in a hnall quantity, 

 and when the water is faturated with it, the excefs of the gas 

 will pa fs into the upper part of the bell. 



*^ This gas, then, is compofed of muriatic acid gas and an 

 fexccfs of oxygen. It is this oxygeti in excefs which, though 

 it be the acidifying principle, deprives it of the whole, or 

 hearly the whole, of its acidity, and renders it lefs foluble in 

 water. This is a h& difiicult to be explained. We have 

 have alreadv faid that an excefs of oxvo-en added to nitrous 

 gas produces in it a Contrary eflc6l ; for it gives it an acidity 

 it did not bef()ffc poffjfs, aiid renders it perfectly foluble in 

 water. It would be difiicult to account for thtfe different 

 eftecSts, but they are hS.s, well attelled, which we ought to 

 adopt though ignorant of the caufe. 



" Oxygeilated muriatic gas is not invlfible like the other 

 gafes; it is of a green ifli- yellow colour, which renders it 

 very perceptible, ft has a ftrong pungent odotir, and i§ 

 dangerous to infpire, becaid'c it excites a violent cough, and 

 hiight occafion a haemorrhage. 



" We have before mentioned that oxygenated muriatic 

 gas is tiot acid, or at lead verv little fo : a proof of this is, 

 that it does not combing, or at leaft very little, with alkalies; 

 and that it has not force fufncient to drive the carbonic acid 

 from the dit^erent bafe? with which it is combined : an Q^t^ 

 produced by all the kitown acid?, howevfei- weak ; bcfides, it 

 does not redden bhie vegetable colours, as it would do if ii 

 were acid. It however deftroys not only hh^dj but alii.) all 



Vol. IX. Mm ' the 



