132 BOARD OF AGRICULTURE. 



B.ut I propose to consider to-night the provisions which nature 

 has made for clothing this earth with vegetation, and so adjusting- 

 plants to the world that they can keep their place in it. In the 

 study of this subject, I have been struck with wonder and admi- 

 ration at the complexity and yet the perfection of the machinery. 

 The whole world is full of springs, and valves, and self-regu- 

 lating adjustments, any one of which ceasing to act, every 

 living thing would perish and the earth become a waste. It is 

 not strange to me that some men, in the glimmering of scientific 

 light, have considered the earth a living thing. Its adjustments 

 and provisions are so perfect for the support of vegetation upon 

 its surface, that it seems like the animal system, secreting and 

 throwing out in every place just the materials needed to carry 

 on the vital processes. Nearly seventy elements are now known. 

 They make up the air, the waters and the solid ground. Many 

 of them are so small in quantity that we do not know their use. 

 About twenty of them make up the great mass of the earth's 

 crust and the organic beings upon it. Now, if one of these 

 abundant elements were blotted out, or essentially changed in 

 its quantity, its nature or its distribution, life would be impossi- 

 ble upon the globe. We speak of such beings as now inhabit it. 

 I will take, for illustration, some of the elements that are gener- 

 ally considered of secondary importance in organic beings. 

 Take potash as an example. None of our higher forms of vege- 

 tation can exist where this substance is wanting in the soil. 

 Suppose this substance were unknown upon the globe, or confined 

 to limited localities, what a change would pass over the whole 

 face of nature. Or take phosphorus. We think of it as a rare 

 substance, and I suppose most people think the worst that would 

 happen to us, if this were swept out of existence, would be the 

 loss of friction matches. But every grass, and grain, and fruit- 

 tree must find phosphorus in the soil or they cannot grow and 

 ripen their seeds. If phosphorus were gone, or essentially 

 changed from what it is, the earth would become a waste, for 

 the higher forms of vegetation would be impossible, and the 

 higher forms of animal life unknown. Man could not exist 

 upon the globe, for bone and brains must both have this element 

 in their composition. 



But there arc four elements — oxygon, hydrogen, nitrogen and 

 carbon, that arc the pillars of all organic structures. 



