COMBINATION OF MERCURY 



As water diilblvcs fomctimcs more, fometimcs 

 lefs, of the white precipitate, ^t may be yet it 

 queflion, whether the muriatic or the nitroivs 

 acid is united with- the mercury in the compofu 

 tion of increurium cofmcticum. Although, in^ 

 deed, I do not deny that fume portion of muria- 

 tic acid exifts in it, as the mode -of preparing .it 

 fcems to indicate, yet I cannot help thinking 1 , 

 that the nitrous acid has the greater .influence 

 on its character, and is chielly inftrumental y ta its 

 production. For if we add a few -drops of nitrat- 

 ed mercury to a dilution of gum arable; thcJiquoc 

 becomes immediately milky, and very fcldoiu 

 recovers its tranlparency though ilill more ni- 

 trated mercury ihould be added. This, milky 

 colour, however, 1 have never feen when the 

 experiment was made with corroiive mercury. 

 Having ihown above, that cofmetic mercury af- 

 fumes the appearance of in ill; when mixed with 

 diflilled water, we infer, that this change of co- 

 lour is occalioned by the nitrated mercury, Co me 

 part of which is dtylroyed by the acceilion of the 

 mucilaginous matter. 



We have now only further to obfervc on this 

 part of our i iibjed, that the method of prepar- 

 ing white mercurial precipitate, as propoled by 

 HII anonymous writer, is yet to be noticed. 

 He allerts, that from the mixture of corroiive 

 mercury with a certain weight of crude mer- 

 cury, a falc is obtained by the application of 



heat 



