CHAPTER II. 



PI.ANTS.-THE AIR.-WATER. 



14. Plants are formed by a re-arrangement of simple sub 

 stances, (or elements,) already existing in (a,) the air, (b,) the 

 water, and (c,) the soil Animals are formed by a re-arrange- 

 inent of these plants, of water, and of air. These changes are 

 not simply mechanical, but chemical ; and are under the direc 

 tion of a power called LIFE, of which very little is yet known. 

 Heat, light, electricity, the wind, the rain, and the sun, have alao 

 a powerful influence over vegetable and animal existence. 



15. Wherever the proper elements and circumstances unite, 

 there will vegetable life exist. 



16. While all plants are composed of a certain quantity of 

 different substances, the various orders of plants demand either 

 a different proportion of the elements; or one requires an 

 element which is not requisite to the existence of another plant. 

 Thus, one species of plants grows in earth containing a large pro 

 portion of potash or soda, as wormwood (artemisia) and aspara 

 gus ; while another requires little or no potash, as Indian corn. 

 One grows in water, without any connection with the soil ; while 

 another grows in the air like the wind-plant of Florida ; or the 

 mistletoe of Europe, forcing its radicles into the sap wood of 

 another tree, 



17. W T hile plants grow naturally where they find the ele 

 ments, and other circumstances necessary for their formation ; 



