ELEMENT AET BODIES. 



81 



Seven non-metallic solids and fluids sulphur, phosphorus, 

 selenium, iodine, bromine, boron, and carbon. 



Three metallic bases of the alkalis potassium, sodium, 

 and lithium. 



Four metallic bases of the alkaline earths barium, stron- 

 tium, calcium, and magnesium. 



Six metallic bases of the earths aluminum, silicum, 

 yttrium, glucinum, thorinum, and zirconium. 



Thirty metals, whose combinations with oxygen produce 

 neither alkalis nor earths 



Of these metals, the first five decompose water at a red 

 heat* The next fifteen do not decompose water at any tem- 

 perature, and their oxides are not reducible to the metallic 

 -state by the action of heat alone. The oxides of the rest are 

 decomposed by a red heat. It may be added, that of the 

 above there are not more than sixteen elementary substances 

 which are of any importance in the formation of the earth 

 itself or the atmosphere which surrounds it, and consequently 

 which possess any especial claim on the attention of the 

 geologist. These substances are 



Oxygen 

 Hydrogen 

 Nitrogen 

 Carbon 



Sulphur 

 Chlorine 

 Fluorine 

 Phosphorus 



Silicum 

 Aluminum 

 Potassium 

 Sodium 



Magnesium 

 Calcium 

 Iron 

 Manganese. 



Of the above elements, oxygen is the most important. 

 It forms more than one-half of the globe, constituting eight 

 tons in every thirty-six of air, eight in every nine of water, 

 nearly a half of the more abundant earths, silica and 

 alumina besides being present in almost all vegetable and 

 animal substances. 



Were these bodies perfectly free to combine with each 



