o- 



ESSAYS AND- OBSERVATIONS 



turned Into a red calx, or Has been firft 

 dilFolved in nmia fortis, and afterwards, 

 by evaporation and calcination, freed 

 from the acid, and reduced to a red pow- 

 der ; if either of thefe red' powders, 1' fay, 

 is digefted' with oil; of vitriol; and made' 

 to boil, this liquor will not now dillblve 

 the mercury, or fo much as change its" 

 colour. On the other Hand, tho' Tpir. 

 fal. mar. is not efteemed a proper men' 

 ftruum of quick-filver in the immerfive 

 way, but when applied to it in form of 

 "Vapour in fublimation ; yet:, if this fpirit 

 is poured upon the red precipitate mfer^' 

 cuiy, it prefently changes its colour ta 

 •white, and quickly dijOTolves it. Again, 

 fpir. fal. m.ar. readily diifolves clean and' 

 frefh fileings of iron: Yet, if thefe are' 

 frequently moiftened-with water, and by- 

 trituration and calcination turned to x 

 crocus ; fp. fal. mar. poured upon this, 

 raifes an eftervefcence indeed, but does^ 

 not feem to make a folution ; for the iron' 

 lies at the bottom' not fenfibly dimini'lied, 

 and the colour of the liquor is not chan- 

 ged. 



