OBSERVATIONS ON MURIATIC ACID, £35 



pording to the metal ; but the falls thus produced are merely 



muriates. In order to form real hyperoxigenized muriates, It muft combin* 

 . . ~. . ,- , . . . r 11 n n * c -j- with the maxi- 



*t is neceffary to take the metal in its tulleit itate or oxidize- mum 0X j<j eSj ^ 



ment, and combine it with the acid, either by double decom- produce h. ox* 

 pofition, or by paffing a current of oxigenized muriatic acid mur ' a 

 gas through the oxide fufpended in water. The acid is thus 

 feparated into muriatic and hyperoxigenixed muriatic acid ; 

 and, in thefe ftates, combines with the metallic oxide. The 

 metallic hyperoxigenized muriates are different, in every re- Thefe greatly 

 fpect, from the metallic muriate?,, Red oxide of iron is dif- r5a * tes> 

 folved with difficulty. Oxide of copper more eafily. Red Habitudes of 

 oxide of lead exhibits the fame appearances, during its combi- ™^ ^"^ 

 nation with this acid, as with nitric acid. When nitric acid is Lead. 

 poured, even in excefs, upon red oxide of lead, only a part of 

 the oxide is diffolved, unlefs heat be applied ; and what re- 

 mains becomes a blackim brown powder. But, if metallic Red oxide of 

 lead be added, in a juft proportion, all the red oxide difap- ^ te " t ^° XJ§e " 

 pears, and none oT the brown powder is formed ; neither is wholly diflblvefi 

 there any difengagement of nitrous gas, when the metallic p a " t * k e ° a ^ **' 

 Jcad is diffolvrd. The precipitates caufed in either cafe, by more oxigcnited 



pouring an alkali into the nitric folution, are yellow. Hence and the other 

 7 . . , - . . , . , part difiblves, 



it appears, that red oxide of lead contains too much oxigen to 



be diffolved by nitric acid. One part of the oxide takes up the 

 excefs of oxigen, and becomes brown ; while the portion 

 which lofes oxigen, becomes yellow, and is foluble in nitric 

 acid. The prefence of metallic lead promotes the total folu- 

 tion of the red oxide, by taking up the fuperabundant oxigen. 

 I found that a current of oxigenized muriatic acid gas, like the Ox. row. acii 

 nitric acid, diffolved a part of the red oxide, and caufed the afts fltni,arl i r - 

 brown powder to be formed, upon which it could not a£i. 

 Hyperoxigenized muriate of lead is much more foluble than Hyp. ox. mm. 

 muriate oYlead; and the acid is very flightly attraaed by the oflead: (o[M ^ 

 bafis. 



But, of all the metallic falts formed by the combination of Mercurial ma- 

 the muriatic acid, in any of its different flates, none fo much ria es * 

 deferve attention as thofe which have for their bales, the ox- 

 ides of mercury. The nature of the falts which refult from the 

 combination of common muriatic acid with the different oxides 

 of this metal, has been ftated in the moft contradictory man- 

 ner, by different chemifts. But, as the knowledge of hyper- 

 oxigenized muriatic acid lias thrown fome light upon the 



true 



