WITH TOE MARINE ACID. 311 



of cor*ofivc mercury, a red powder is precipi- 

 tated. If the acid is in considerable quancity, 

 the colour of the precipitate will be proportio- 

 nally paler, and will become perfectly white if 

 the cxccfs of acid is very rcat. The fmallcft 

 particle of lixivial fait, although the acid be in a 

 large proportion, will precipitate fome of the 

 corrofive mercury, which is however in a fhort 

 time again dilfolved. Petermaa * is of opinion, 

 that the red colour is owing to martial vitriol ; 

 but Teichmeyer conceives it fliould be attribut- 

 ed to the fulphureous parts of the falts. It is 

 certain indeed that a red powder can be prepa- 

 red without any vitriol. 



Volatile alkali alfo decompofes the folution of 

 corrofive mercury. If it is pure, it precipitates 

 a white powder; but, if it is charged with any 

 fatty fub fiance, (as in the vinous ipirit offal 

 ammoniac,) the precipitate is of an afh-colour f. 

 From the plogifton in the volatile alkali, it 

 fomctimcs happens, that a dark afli-coloured 

 or black powder is precipitated. 



According to Meyer t, an ounce of lime-wa- 

 ter is capable of precipitating two grains of cor- 

 rofive mercury of a yellow colour, which, on 

 being dried, changes gradually to black. This 



Y 3 is 



* Chcmia, 1708. 



I Zimmerman in Zuf.U7.cn zu Ncumaru Chcmifchcn Vor- 

 kfungen. 



i Abhandlung vom ungclofchtcn KalcK. 



