THE VOLATILE PART OF PLANTS. 31 



ciura, magnesium, iron, and manganese, as well as oxygen, 

 carbon, and nitrogen.* 



These fourteen bodies are elements, which means in 

 chemical language, that they cannot be resolved into other 

 substances. All the varieties of vegetable and animal 

 matter are compounds, are composed of and may be re- 

 solved into these elements. 



The above fourteen elements being essential to the or- 

 ganism of every plant and animal, it is of the highest im- 

 portance to make a minute study of their properties. 



2- 

 ELEMENTS OF THE VOLATILE PART OF PLANTS. 



For the sake of convenience we shall first consider the 

 elements which constitute the destructible part of plants, 

 viz. : 



Carbon, Hydrogen, 



Oxygen, Sulphur, 



Nitrogen, Phosphorus. 



The elements which belong exclusively to the ash will 

 be noticed in a subsequent chapter. 



Carbon, in the free state, is a solid. We are familiar 

 with it in several forms, as lamp-black, charcoal, anthracite 

 coal, black-lead, and diamond. Notwithstanding the 

 substances just named present great diversities of appear- 

 ance and physical characters, they are identical in a cer- 

 tain chemical sense, as by burning they all yield the same 

 product, viz. : carbonic acid gas. 



That carbon constitutes a large part of plants is evident 

 from the fact that it remains in a tolerably pure state after 

 the incomplete burning of wood, as is illustrated in the 

 preparation of charcoal. 



* Earely, or to a slight extent, lithium, rubidium, iodine, bromine, fluorine, 

 barium, copper, zinc, and titanium. 



