124 plint's natural history. [Book XXXIII. 



CHAP. 41. (8.) — HYDRA RGTROS. REMEDIES DERIVED FROM 

 MINIUM. 



Human industry has also discovered a method of extracting 

 hydrargyros'^ from the inferior minium, a substitute for quick- 

 silver, the further mention of which was deferred, a few pages 

 before,^ to the present occasion. There are two methods of 

 preparing this substance ; either by pounding minium and 

 vinegar with a brazen pestle and mortar, or else by putting 

 minium into flat earthen pans, covered with a lid, and then 

 enclosed in an iron seething-pot well luted with potter's clay. 

 A fire is then lighted under the pans, and the flame kept con- 

 tinually burning by the aid of the bellows ; which done, the 

 steam is carefully removed, that is found adhering to the lid, 

 being like silver in colour, and similar to water in its fluidity. 

 This liquid, too, is easily made to separate in globules, which, 

 from their fluid nature, readily unite.^^ 



As it is a fact generally admitted, that minium is a poison,^^ 

 I look upon all the recipes given as highly dangerous which 

 recommend its employment for medicinal purposes ; with the 

 exception, perhaps, of those cases in which it is applied to the 

 head or abdomen, for the purpose of arresting haemorrhage, 

 due care being taken that it is not allowed to penetrate to the 

 viscera, or to touch any sore. Beyond such cases as these, for 

 my own part, I should never recommend it to be used in 

 medicine. 



CHAP. 42. THE METHOD OF GILDING SILVER. 



At the present day silver is gilded almost exclusively by 

 the agency of hydrargyros f^ and a similar method should 

 always be employed in laying gold leaf upon copper. But 

 the same fraud which ever shows itself so extremely inge- 

 nious in all departments of human industry, has devised a 



79 Or artificial quicksilver. In reality, hydrargyrus is prepared from the 

 genuine minium of Pliny, the cinnabar mentioned in Chapter 36 : it being 

 obtained by the sublimation of sulphuret of mercury. 



80 In Chapters 20 and 32. 



*^ This, probably, is the meaning of " lubrico humore compluere." 



92 See the end of Chapter 38. 



^3 Artificial quicksilver is still used for this purpose. See Note 24 to 

 Chapter 32 of this Book ; also Beckmann's Hist. Inv. Vol. II. p. 295. 

 Bohn's Edition, 



