MAGNESIA AND MAGNESIUM. 



283 



atom of oxygen. Consequently, the weight of 

 an atom of magnesium must be 1-5. 



From the details contained in the different 

 sections of this chapter, it is evident that the 

 fixed alkalies and alkaline earths are all anala- 

 gous substances, being each a compound of one 

 atom of a metallic basis, and one atom of oxy- 

 gen. Potassium, sodium, and barium combine 

 with two doses of oxygen ; though this has not 

 been shown to hold with the other four bases 

 contained in this chapter, yet it is probable, from 

 the striking analogy between the properties of 

 all these bodies, that they will be found hereafter 

 to be in the same predicament. 



Lithia is the lightest, and barytes the heaviest 

 of these bodies. It may be worth while to sub- 

 join a tabular view of the atomic weights of the 

 metallic bases and the alkalies, arranged accord- 

 ing to the weight. 



ATOMIC WEIGHTS. 



ALKALIES. ATOMIC WEIGHTS. Table of 



the atoms 

 of the alka- 

 line metals 

 and alka- 

 lies. 



