SODIUM. 235 



which is soluble in water, and may be washed away 

 from the metal which has been produced. 



SODIUM. 



581. PROPERTIES. The metal sodium is 



Sodium de- 

 scription, similar in its properties to potassium. It 



^dvni^and * s P re P are d by similar means, from carbo- 

 occurrcnce? nate of soda, and may be employed by the 

 chemist, for the same purpose. It occurs, principally, 

 in nature, in the form of common salt. Thrown upon 

 water, it decomposes it, without however igniting the 

 hydrogen which is evolved.* Sodium is readily sol- 

 uble either in water or acids. 



582. USES OF SODIUM. Sodium is now 



.For K'hat pur- . 



pose is it prepared in large quantities, in France, 



as a material to be used in the manu- 

 acture of the metal aluminiu n. Its cost, a few years 

 since, was ten dollars an ounce. It can now be pro- 

 cured for less than a dollar per pound. 



AMMONIUM. 



583. Ammonium is a compound of ni- 



Wkat is said . . 



of ammoni- trogen and hydrogen, which is presumed 

 um ' to be a metal. Its molecule contains one 



atom of nitrogen, to four of hydrogen. If a metal, it 

 differs from all others, in being a compound, and not a 

 simple element. There are, however, good grounds 



* If sodium is wrapped in paper, to prevent waste of heat, it burns 

 with flame, like potassium, upon water. 



