SODIUM. 73 



spreading the ashes upon the land. According 

 to Pliny, the ancient Britons used to burn their 

 wheat straw and stubble, and scatter the ashes 

 upon the land. 



On the farm, no substance containing potash 

 should be allowed to go to waste. Every parti- 

 cle of wood ashes, leached and unleached, should 

 be applied to the soil, together with the ashes of 

 dead branches of trees, of weeds and of leaves, 

 and of whatever contains potash. By this 

 means the farmer may often obtain a supply, 

 more cheaply than in any other shape. 



SODIUM. 



Sodium is a solid ; and was discovered by Sir 

 H. Davy, in 1807. It is lustrous, and of a yel- 

 lowish-white color, more nearly resembling silver 

 than potassium, to which, in other physical pro- 

 perties, it is similar. When heated in air or 

 oxygen, it burns with a bright yellow flame. 

 Like potassium, it is lighter than water, which 

 it decomposes with great rapidity, liberating the 

 hydrogen and combining with the oxygen, thus 

 forming soda, which, having an affinity for 

 water, combines with a certain amount of it, 

 and becomes the hydrate of soda caustic soda 

 of commerce. Soda was originally obtained from 

 the ashes of marine plants, but is now obtained 



