246 METALS. 



but is more readily reduced by hydrogen. A cur- 

 rent of this gas being made to pass through a hot 

 tube containing the oxide, it combines with oxygen, 

 and passes off with it as water, leaving the metal in the 

 form of a fine powder. Its proper solvents are the 

 same as those of iron and chromium. The solutions 

 of cobalt are pink. The oxide is employed for im- 

 parting a blue color to glass. 



NICKEL. 



Nickel 609. Nickel is still another grey metal, 



' l[ 8 hiQ * in color and more malleable than 



ores, solvents, cobalt, and not much affected by the air. 



and uses? * * i i " 



It is round in combination with copper, in 

 the mineral called copper nickel. It may be prepared 

 by either of the methods used for cobalt. Its proper sol- 

 vents are the same as those of the last four metals. The 

 solutions of this metal are green. Nickel is principally 

 used in the preparation of the alloy called German sil- 

 ver. This imitation of silver is brass rendered white 

 by the proportion of nickel which it contains. The 

 alloy is composed of one hundred parts of copper, six- 

 ty of zinc, and forty of nickel. 



ZINC. 

 610. DESCRIPTION. Zinc is a bluish- 



de- 

 scription, white metal, readily tarnished in the air. 



Jt is brittle at ordinary temperatures, and 

 converted into vapor at a red heat. If 



