97 



CHAPTER III. 



METALLIC ELEMENTS — THE ALKALIES — THE ALKALINE 

 EARTHS, AND THEIR SALTS. 



196. In classifying the elementary substances, the 

 first and most obvious arrangement seems to be that 

 of dividing them into non-metallic and metallic ; the 

 former including oxygen, chlorine, &c., or the sup- 

 porters of combustion as they are sometimes called, 

 together with the non-metallic simple combustibles, 

 such as carbon and sulphur, &c. ; whilst the latter 

 includes iron, gold, lead, tin, and all the ordinary 

 metals, as well as a number of very scarce metals ; 

 some of which, however, are very abundant in a state 

 of combination, though they are hardly ever met with 

 in a pure and separate form. 



197. In the pure state, the metals are chiefly im- 

 portant for their strength, hardness, malleability, and 

 other mechanical properties; their interest to the 

 chemist is for the most part confined to their combi- 

 nations, and the difi'erent compounds which they 

 form by combining in. various ways, with the non- 

 metallic elements. The oxides, or the substances 

 which the metals form by uniting with oxygen, are 



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