l6a Inquiry into ihe Laws of AJlmt^. > 



between the mercury mod oxigenatcd, and that leaft To : it appears that all tlie Intermediate 

 "proportions may exift, as I have obferved with refpecl to the fulphates. 



When the nitrate of mercury is precipitated by the muriate of foda, mercurial muriates 

 are obtained, which differ according to the OKidation of the mercury. With the nitrate 

 little oxided a white precipitate is obtained, which retains a part of the nitric acid, and 

 cannot be diflblved in the muriatic acid, nor be taken up by the concentrated nitric acid^ 

 without giving out much nitrous gas. From the folution prepared by heat, a precipitate 

 is obtained rather of a yellow colour, which is not folublc in the muriatic acid, but readily 

 diflblves in the nitric acid, giving out little nitrous gas. The fupernatant fluid affords by 

 evaporation, a little corrofive mercurial muriate. 



If the experiment be made with a nitrate, prepared in fuch a manner that the mercury 

 fhall be in the moft oxided ftate, and has not re-dilTolved any metallic mercury, and if it 

 be diluted with a confiderably large quantity of water, no precipitate is formed, but all the 

 mercury is found in the ftate of corrofive mercurial muriate : neverthelefs, it is not obtained 

 in this ftate but in a limited quantity, and fometimes even none is had, according to the 

 proportion of muriate of foda employed, becaufe the corrofive mercurial muriate has the 

 property of forming with the nitrate of foda a quadruple fait. 



This fait is capable of forming rhomboidal cryftals, grooved on their face, of a confide- 

 rable fize : it fufes upon ardent charcoal ; by expofing it tp a fufficient heat in a retort, all 

 the mercury is feparated in the form of corrofive mercurial muriate. The refidue is a nitrate 

 of foda which retains a little muriatic acid, fo that the feparation which takes place is de- 

 cided by the refpeftive volatility of the fubftances, and by a difference of affinity between 

 the nitric acid and the muriatic acids relative to the oxide of mercury. 



After the cryftallifation of this fait, another is obtained in fmall needles, which appear to 

 be a complex fait, in which the oxide of mercury is found in a greater proportion. 



Nothing certain can be cftablifhed as to the refults of the mixture of the nitrate of mer- 

 cury highly oxided, and the muriate of foda, becaufe they vary according to the propor- 

 tions of the fubftances which aft. 



From the preceding obfervations we deduce, that the nitric folution of mercury may hold 

 this metal in folution from the loweft degree of oxidation to the higheft, or to that which 

 is required for the conftitution of corrofive mercurial muriate ; that it may pofTefs it in all 

 the intermediate degrees, but that its properties will be different according to the degree 

 of oxidation. 



5. Fourcroy lays it down as a principle, that any metallic oxide whatever gives to acids 

 a colour fimilar to that which it has itfelf ; whence he concludes, that when a m.ercurial 

 precipitate which proceeds from a white fait acquires another colour, a change muft have 

 been made in the oxidation. This opinion does not appear to me to be well founded. 



I took fome muriatic acid, and difTolved in it fome red oxide of mercury ; the folution 

 was eafily efFe£l:ed, without any difengagement either of oxigen gas, or oxigenated muriatic 

 acid : it fpontaneoufly afforded fine cryftals of corrofive mercurial muriate. I may here 



remark, 



