AGENCY OF MAN. Ill 



not develope itself without his care and skill. He cannot act 

 directly upon the functions of plants, as the other agents do, 

 but he can modify, and, to a certain extent, control the influ- 

 ence of those agents. He must learn the conditions required 

 for their beneficial action. He is the overseer, who brings 

 together natural powers, that they may act usefully upon 

 each other, and upon the materials which are to be manufac- 

 tured. And although his agency is secondary, still it is not 

 less necessary or beneficial, than if he could cause his crops 

 to grow by direct power ; for although the agents we have 

 described, act with their own efficiency, and according to 

 their own fixed laws, still they are under the control of the 

 farmer, to a much greater extent than he supposes. 



In reference to the vital power itself, we have already seen 

 the agency of the farmer : he must supply it with certain con- 

 ditions, proper food, soil, tillage, etc. before he can expect a 

 bountiful crop. The other agents are perhaps less under 

 his control, and it may be asked by some, of what use a de- 

 scription of them can be to a practical farmer. On the sup- 

 position that the atmosphere, water, light, heat and electrici- 

 ty, do exert all the influence which is claimed for them, are 

 they not beyond the control of man ? How can the farmer 

 make the sun shine warmer or brighter, or the rains and 

 dews descend in greater or less quantities ? How can he 

 control those mysterious powers of electricity and aflSnity, 

 whose universal agency is witnessed by all ? These inquiries 

 arise from an erroneous idea of the case, from a false idea of 

 the processes above named. It is because these agents are 

 under the control of the farmer, not directly but incidentally, 

 that they are brought forward for his consideration. Their 

 agency is not a matter of mere science, but of practical utili- 

 ty, of vast importance to every man who attempts to cultivate 

 even a garden. 



1. The atmosphere and its contents. How can the farmer 

 employ this agent 1 He can secure its agency by so prepar- 



