ARSENIC, ANTIMONY, BISMUTH. COPPER AND LEAD. 261 



is very likely to be, the copper is set free by the formation 

 of an acetate of iron. 



369. Lead. Next to iron, lead is one of the most abun- 

 dant metals. Its softness and low melting-point are its 

 chief characteristics. It is used for a great variety of pur- 

 poses. It is the chief ingredient in type-metal. Bullets 

 and shot are made from it. The mode of manufacturing 

 shot is given in 60, Part I. It is also largely used for 

 pipes for conducting water and other liquids. In the form 

 of sheet-lead it is applied to various uses. This metal is 

 obtained principally from its sulphide, called galena. One 

 mode of obtaining it is to mix the ore with iron, and then 

 apply heat. The sulphur, having a greater attraction for 

 iron than for lead, leaves the lead to unite with the iron. 

 The action of water upon lead we shall speak of in another 

 place. 



370. Oxides of Lead. The monoxide of lead, PbO, is a 

 yellow substance called massicot. If this be melted with 

 a strong heat it solidifies, on cooling, into a reddish-yellow 

 mass composed of brilliant scales, and is called litharge. 

 It is used extensively in the arts, in the manufacture of 

 glass, in making the lead plaster of the apothecary, in form- 

 ing a varnish with linseed-oil for the cabinet-maker, in the 

 manufacture of wliite-lead, red-lead, etc. The red oxide is 

 prepared by exposing for some time to a faint red heat the 

 monoxide which has not been fused. A brilliant red and 

 very heavy powder results called minium, which is used 

 as a cheap substitute for vermilion in painting. 



The composition of the red oxide is 2PbO.PbO 2 , being a 

 compound of the monoxide and of a chocolate-colored ox- 

 ide, PbO 2 , not previously mentioned. 



371. "White-Lead, or Carbonate of Lead, PbCO 3 . This may 

 be prepared by mixing a solution of lead acetate or nitrate 

 with one of sodium carbonate, a white precipitate settling. 



