128 ESSAY VI. 



obtained at first corrosive sublimate in the neck of the 

 retort, and afterwards arsenic. Hence it would follow that, 

 as the quicksilver in the corrosive sublimate is calcined, the 

 muriatic acid has a stronger attraction for arsenic than for 

 the calx of quicksilver. In order to ascertain this point, I 

 mixed butter of arsenic with calcined quicksilver, and 

 distilled the mixture. I first obtained some drops of the 

 butter in the receiver, then corrosive sublimate rose into 

 the neck of the retort, which was at last followed by 

 arsenic. But the case is quite different with the regulus 

 of arsenic ; for if it be mixed with an equal quantity of 

 corrosive sublimate and distilled, smoking butter of arsenic, 

 niercurius dulcis, and a little quicksilver, are obtained. 

 Hence it follows that mercurius dulcis is decomposed by 

 a double elective attraction, that of the phlogiston of the 

 regulus for the calx of mercury, and that of the muriatic 

 acid for the calcined regulus of arsenic, whence the quick- 

 silver is reduced/ and butter of arsenic is produced. The 

 same thing happens with a mixture of orpiment and 

 corrosive sublimate. 



SECTION XXVI. UPON COPPEE. 



(a) Copper is attacked by the acid of arsenic during 

 digestion. The solution is of a green colour. A quantity 

 of light blue powder is deposited, and attaches itself to the 

 copper. This powder consists of acid of arsenic and calcined 

 copper, (b) One part of filings of copper was mixed with 

 two parts of dry acid of arsenic, reduced to a fine powder. 

 The mixture was exposed to distillation, and the fire 

 increased till the retort melted. Here some arsenic rose 

 into the neck, the mass entered into fusion, and turned 

 blue. After the retort was cooled, I poured some water 



