POTASSIUM AND SODIUM. 207 



Fig. 85. 



basket, b x c c?, which is filled with ice. The object of this 

 is to condense the vapor of the metal, while the gas, the car- 

 bonic oxide, is allowed to escape through an opening. The 

 condensed metal falls to the bottom of the reservoir into 

 some mineral naphtha. This is a liquid which contains no 

 oxygen, its ingredients being only carbon and hydrogen, 

 and therefore it will not have any effect upon the potassium. 

 There are some minute details in this process w T hich we have 

 omitted in order that the main points may be clear to you. 

 The process is expensive and difficult, and the metal is 

 obtained in small quantities, and therefore it bears a high 

 price. 



284. Properties of Potassium. Potassium is so light that 

 it floats on water. It is a white metal with a cast of blue, 

 and is very brilliant in its lustre if a piece be cut so as to 

 expose a fresh surface. But so great is its attraction for 

 oxygen that the cut surface immediately tarnishes from 

 uniting with the oxygen of the air, and if left exposed to 



