162 ESSAY XI. 



fore leaves the acid, and that this latter uniting with the 

 regulus goes over into the receiver in the form of butter ; 

 that at last, on increasing the heat, the mercury goes over 

 by itself, or that it is sublimed in union with the sulphur of 

 antimony, under the name of cinnabar of antimony, provided 

 crude antimony (antiinonium sulphuratum) be taken for this 

 purpose instead of the regulus. 



This explication does not agree with the late observa- 

 tions in chemistry ; for the butter of antimony, or, as it is 

 sometimes called, the antimonial caustic, contains not the 

 least regulus of antimony; but the portion of antimony 

 which it contains is half-calcined, and this calcination cannot 

 be owing to the muriatic acid. But as it is well known 

 that the mercury in the corrosive sublimate is not in a 

 reguline form, but in the state of a calx, and that the 

 mercurial calx in this metallic salt may be reduced by 

 being put upon live coals ; that fuming muriatic acid goes 

 over, if the corrosive sublimate is distilled with phlogistic 

 substances ; and, further, that the corrosive sublimate is by 

 no means decomposed when distilled with pulvis algarothi, 

 or with a half-calcined regulus of antimony ; it follows that, 

 in the present process, the mercurial calx, as one constituent 

 part of the corrosive sublimate, attracts the phlogiston neces- 

 sary for its reduction from the regulus of antimony, whereby 

 the muriatic acid is set free, and then attacks the regulus 

 of antimony, which is dephlogisticated in the same propor- 

 tion, and goes over united with it in the form of a thick 

 substance, resembling butter. 



The butter of antimony consists, therefore, of concen- 

 trated muriatic acid, and of a half-calcined regulus of 

 antimony ; and it is from this partly dephlogisticated regulus 

 that the antimonial tartar is obtained when it is united with 

 cream of tartar. The regulus of antimony must be only 



