VI. METALS.— Oxides of. 237 



time dissolve also copper jj in another parcel of nitric acid ; mix 

 the two solutions, evaporate to dryness, and calcine the residuum 

 in a shallow vessel till no more red fumes appear ; caustic. 



LEAD. 



Dross of lead, Plumbum ustum. Melt lead, and rake oft* the 

 scum till it is entirely reduced to dross. 



Massicot, Protoxide of lend, Ochra jylumharia fact'tfia. Roast 

 potters' lead ore, or dross of lead, until it acquires a yellow colour. 

 Used as a paint; comp. of 13 lead, 1 oxyg. ; equiv. 14. 



Litharge of gold, Litharqijrm auri. Yellow, impure. 



Litharge of silver, Litharr/ijnis argcnti. White; obtained 

 in the extraction of silver; from Germany. 



English litharge, Litharr/i/nis^ Plumhioxidum semivitrcum. 

 Made by melting red lead ; used in making plaisters, being more 

 convenient than red lead, and from its peculiar scaly appearance 

 it cannot be adulterated. In grinding litharge, \il oz. of olive 

 oil are usually added to each cwt. to prevent dust. 



Red lead, Minhim^ Plumhi oxidnm ruhiiim. By roasting 

 litharge in a flaming fire; used in making plaisters, and as a 

 paint ; reduced by red earths, a mixture of the protoxide and 

 deutoxide of lead. 



Orange red, Sandix, Made by calcining white lead ; is a 

 brighter colour than red lead. 



IRON. 



Loadstone, Magnes. Found in iron mines; astringent; used 

 externally to draw iron out of wounds, also as an amulet against 

 the gout, and to draw over or stroke certain parts in painful dis- 

 eases, as a magical remedy. 



Blood-stone, I^pis luEvmtitis, Hcpmatitis. Found in mines; 

 made into polishers, and when prepared, used also as a polishing- 

 powder ; drying, astringent, agglutinating. 



Scales of iron, lUark oxide of iron ^ Protoxide of iron, S(/i/amre 

 fn-ri, Oxidumferri nir/rnm. The scales of iron beaten off by the 

 blacksmith in his work, separated from the dirt by means of a 

 magnet, reduced to powder in a mortar, and washed over; do not 

 occasion flatulence. Composed 3*5 iron and 1 ox. ; e(|uiv. 4-5. 



yETHiops MARTI ALis. Keep iron filings under water, shaking 

 them occasionally ; wash the black powder, and dry (juickly to 

 prevent its rusting. 



Chalyrs I'Rki'ARATUS cum aceto. Wet steel dust with 

 ivhite wine vinegar, expose it to the sun ; rejwat this often, then 

 levigate. 



