Chap. 33-1 Corrofive S ultimate. 209 



The muriatic acid has no action on mercury in its me- 

 tallic ftate, becaufe that acid cannot part with the oxygen 

 neceflary to calcine the metal. It has, notwithstanding, 

 a very ftrong attraction for mercury, and diffolves it 

 with great readinefs when the latter is previoufly re- 

 duced to the ftate of a calx. If a fmall quantity of 

 muriatic acid is poured on a nitrous folution of mer- 

 cury, it feizes the metal, and forms a fait, which is 

 precipitated in the form of a whitifh coagulum, which, 

 when dried, is called white precipitate, and is a kind 

 of corrofive fublimate. The marine falts, with a bafis 

 of alkali, or of any faline terreftrial fubilance, fuch 2S 

 lime, magnefia, &c. produce the fame effect, except 

 that in this cafe, though the precipitate is the fame, 

 the nitrous acid, inftead of being left uncombined, 

 unites with the bafis of the marine fait which was em- 

 ployed. 



If mercury, corroded by the vitriolic or nitrous 

 acids, and dried, is mixed with powdered fea fait, and 

 expofed to heat, a double attraction takes place ; the 

 nitrous or vitriolic acid deferts the metal to unite with 

 the fixed alkali of the common fait, while the muriatic 

 acid ieizes upon the mercury, and forms a metallic 

 fait, which, in the degree of heat neceflary for the ope- 

 ration, proves volatile, and, riling in vapour, is con- 

 clenfed in a folid form in the upper and cool part of the 

 vefiel employed. This is the hydrargyrus muriatus, 

 or corrofive fublimate, which is a very acrid and pow- 

 erful preparation of mercury. 



The mild preparation, called calomel, is obtained by 

 rubbing three parts of mercury, in its metallic ftate, 

 with four of corrofive fublimate, till they form a greyifh 

 powder; the mafs is then fublimed*, and forms a 

 fubftance like corrofive fublimate, but more ponderous, 



* Made volatile, or railed in vapour, lay the application of beat. 



VOL. II. P and 



