ZINC. 247 



heated somewhat above the temperature of boiling wa- 

 ter, it can be rolled into sheets. At a higher tempera- 

 ture it again becomes brittle. Sulphuric and muriatic 

 acids dissolve it readily, forming colorless solutions. 

 It is not found native. The red oxide, and the carbon- 

 ate, called calamine, are among its more important ores. 

 611. PRODUCTION. Zinc is produced 

 produced? from its oxide by heating with charcoal to 



remove tne ox yg en ? or > m other words, to 

 reduce it. When made from the carbonate, 

 the ore is previously roasted, to expel 

 its carbonic acid and bring it to the 

 state of oxide. As the metal is volatile 

 at the heat required in its reduction, an 

 ordinary furnace, such as is used for making iron, can- 

 not be employed in the process : the metal would be 

 lost in vapor. A clay retort, or muffle, such as is re- 

 presented in the figure, is used instead. The zinc va- 

 por condenses in the cool neck, and falls, in drops of 

 melted metaLinto a vessel of water placed to receive 

 it. The carbonic oxide produced in the process at the 

 same time, escapes into the air. It will be observed, 

 that the process is essentially the same as that for pro- 

 ducing potassium and phosphorus, as before described. 

 Acids dissolve zinc, forming colorless solutions. 



612. ACTION OF HEAT AND AIR. Zinc 



How may zinc - : - 



be burned? may be burned by heating it on charcoal, 

 in the blow-pipe flame. It melts, and con- 

 verts itself rapidly in the process into 

 white oxide of zinc. If an intense 

 heat is employed, the vapors of the 

 metal burst through the crust and burn 



