118 THE YEGKETABLE KINGDOM. 



which had formed on the surface. The seeds of some plants 

 are furnished with minute wings or plumes which cause 

 them to be borne on the air or floated on the water (fig. 4), 



to fertilise some barren spot, 

 perhaps a coral reef which has 

 at length reached the surface 

 of the water and which ascends 

 no higher, for the little crea- 

 tures which built it are aquatic 



FIG. 4.-SEEDS WITH PAPPI. ^ ?***<?. llv6 fP 08 ^ tf) 



the air ; this coral reel now 



becomes a receptacle for sea-weed and fungi, which float 

 on the surface of the ocean, are washed on to the reef, die, 

 decay, and leave behind a thin layer of mould, which process 

 being repeated again and again, forms an elevated edge 

 to the reef, enclosing a lake or "lagoon" as it is called, the 

 waters of which evaporate and the space is filled up in the 

 same way as the edge was formed, together with the excre- 

 ments of birds, &c., forming layer after layer of mould, and 

 the 'surface becomes fit for the growth of larger seeds, as the 

 cocoa-nut, banana, &c., which are drifted on to it by the 

 waves ; in this way a coral reef becomes an island fit to be 

 inhabited by man and other animals. 



The vegetable kingdom forms a mysterious link between 

 the mineral and animal kingdoms, and binds all creation 

 into one grand and unspeakably beautiful whole. There 

 are certain substances from which the vegetable derives its 

 nourishment, namely water, carbonic acid, and ammonia, 

 which, though strictly inorganic, are yet not simple or 

 elementary substances, but consist of pairs of elements 

 combined. Thus water consists of oxygen and hydrogen, 

 carbonic acid of oxygen and carbon, and ammonia of 

 hydrogen and nitrogen. All these aliments of the vegetable 

 kingdom exist in the air, and in sufficient quantities to 

 supply all the requirements of vegetation ; so that the air, 

 together with a few metallic oxides (salts) derived from the 

 earth, furnishes food for the whole vegetable tribe, from the 

 highest to the lowest, and these vegetables in their turn 

 supply all the food which the animal tribes consume, for 



