262 FIXED ALKALIES AND ALKALINE EARTHS. 



3. Sodium, like potassium, combines with an 

 additional dose of oxygen, and forms a solid of a 

 greenish yellow colour, distinguished by the 

 name of peroxide of sodium. From the expe- 

 riments of Gay^Lussac and Thenard, it appears, 

 that sodium in the peroxide is united with 1 

 times as much oxygen as in soda.* Hence, the 

 peroxide is composed of 



Sodium 3 



Oxygen 1-5 



4-5 



So that the atomic weight of this peroxide is 4*5, 

 and it is a compound of 1 atom sodium and li 

 atom oxygen ; or of 2 atoms sodium and 3 

 atoms oxygen. It is curious that soda has a 

 tendency to combine in the same proportion, 

 with several of the acids, that sodium does with 

 oxygen. 



SECT. III. 



OF THE ATOMIC WEIGHTS OF LITHIA AND 

 LITHIUM. 



THOUGH litliia has been known for only a few 

 years, and though it has been hitherto procured 

 only in small quantities, yet its properties have 



Uccherches Physico-Chcm. I. 152. 

 9 



V 



