ESSAY XL 



A CHEAPER AND MORE CONVENIENT METHOD OF 

 PREPARING THE PULVIS ALGAROTHI. 1778. 



THE preparation of this powder, as has hitherto been prac- 

 tised, is an operation very difficult, and dangerous to the 

 health. As this powder is requisite in order properly to 

 prepare antimonial or emetic tartar, I resolved to try whether 

 the preparation would not succeed without corrosive subli- 

 mate, by which means two considerable advantages would 

 be gained : the chemist would be out of danger, and the 

 great quantity of the first-mentioned mercurial preparation, 

 which is now employed for making this powder, would be 

 saved. Both these purposes we obtain by preparing mer- 

 curius dulcis via humida. For the objection, that no cin- 

 nabar of antimony is obtained, is groundless ; because this 

 cinnabar, purified by sublimation, is in no respect different 

 from the common pure cinnabar. 



Before I proceed to describe the new process for pre- 

 paring the pulvis algarothi, it will be necessary to inquire 

 into the theory which has been hitherto received concerning 

 the production of butter of antimony when regulus of anti- 

 mony is distilled with corrosive sublimate. It is said that 

 the decomposition of the corrosive sublimate, which in this 

 case happens, takes place because the elective attraction of 

 the regulus of antimony for the muriatic acid is greater 

 than that of the quicksilver for the same acid ; that it there- 

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