COPPER. 40 1 



potassium and diluted, it becomes the permanganate of potassium, and is 

 used as "Condy's fluid." It readily oxides organic matters, and is thus a 

 disinfectant. It crystallizes in long, deep, red needles, which are dissolved in 

 water. It is a standard laboratory test. There are other compounds, but 

 in these pages we need not detail them. 



COBALT and NICKEL occur together. They are hard, brittle, ana 

 fusible. The salts of cobalt produce beautiful colours, and the chloride 

 yields an "invisible" or sympathetic ink. The oxide of cobalt forms a blue 

 pigment for staining glass which is called " smalt." Nickel is chiefly used in 

 the preparation of German silver and electro-plating. The salts of nickel 

 are green. Nickel is difficult to melt, and always is one of the constituents 

 of meteoric iron, which falls from the sky in aerolites. It is magnetic like 

 cobalt, and is extracted from the ore called kupfer-nickel. A small United- 

 States coin is termed a " nickel." 



COPPER is the next metal we have to notice. It has been known for 

 centuries. It is encountered native in many places. The Cornish copper 

 ore is the copper pyrites. The 

 fumes of the smelting works are 

 very injurious, containing, as they 

 do, arsenic and sulphur. The ground 

 near the mines is usually bare of 

 vegetation in consequence of the 

 " smoke." Sheet copper is worked 

 into many domestic utensils, and 

 the alloy with zinc, termed Brass, is 

 both useful and ornamental. Red 

 brass is beaten into thin leaves, and 



is by SOmC Supposed tO be " gold Fig> 4.-Native copper. 



leaf " ; it is used in decorative work. Bronze is also an alloy of copper, as 

 are gun-metal, bell-metal, etc. 



Next to silver, copper is the best conductor of electricity we have. It 

 is very hard and tough, yet elastic, and possesses malleability and ductility 

 in a high degree. It forms two oxides, and there are several sulphides; the 

 principal of the latter are found native, and worked as ores. The sulphate 

 of copper is termed blue vitriol, and is used in calico-printing, and from it 

 all the (copper) pigments are derived. It is also used in solution by 

 agriculturists to protect wheat from insects. When copper or its alloys are 

 exposed to air and water, a carbonate of copper forms, which is termed 

 verdigris. All copper salts are poisonous ; white of eggs is an excellent 

 remedy in such cases of poisoning. 



LEAD is obtained from galena, a sulphide of lead. It is a soft and 

 easily-worked metal. When freshly cut it has quite a bright appearance, 



26 



