62 MASSACHUSETTS AGRICULTURE. 



But the dignity and worth of your calling is shown not only 

 by the great fruits of its labors and progress, but by the large 

 requirements it makes of those who would prosecute it with 

 skill and success. To subdue the earth and to replenish it. 

 To subdue the earth, we must understand its powers, or laws 

 of growth and production, and must so prepare the soil as to 

 give the freest and fullest play to those laws ; science must be 

 combined with art — the culture of the mind with the culture 

 of the soil. 



The plant that springs up at my feet, on what food does it 

 feed? What condition of the soil is necessary to ripen and per- 

 fect its fruit? To answer these questions, which every season 

 repeats to the farmer, is the province of science. The plant 

 must have nutriment. I will feed it. But will the manure on 

 my fork assist or check its growth ? Will any of its properties 

 enter into the composition of the plant ? Again, I plant wheat 

 in my field this year. It takes up for its nourishment and 

 nearly exhausts certain properties of the soil. What shall I 

 do? Science gives the answer. She says sow a root crop the 

 next year, and while you are raising the root crop the influence 

 of the atmosphere on the soil, aided by culture, will prepare 

 and render soluble the food which will supply the wheat the 

 year after. It is thus we can understand the remark of Pro- 

 fessor Johnston, that the art of agriculture is almost entirely 

 a chemical art, [and that nearly all its processes are to be 

 explained upon chemical principles. 



And this is true, I conceive, not only of what may be called 

 the natural but the mechanical processes of agriculture. The 

 mere passing of the ploughshare or the harrow through the soil 

 can have, of itself, no effect in increasing its productive powers. 

 How, then, does the deep ploughing of dry land and the stirring 

 of its subsoil increase its fertility? Mainly by increasing its 

 power to absorb water, through whose gentle agency the food of 

 plants is dissolved and held in solution for its use. " This 

 power of land to absorb water," Mr. Humphrey says, " de- 

 pends in a great measure upon the division of its parts. The 

 more divided these arc, the greater its absorbent j)0vver. When 

 this pov/er is great, the plant is supplied with moisture in dry 

 seasons. The effect of evaporation in the day is counteracted 

 by the absorption of aqueous vapors from the atmosphere, by the 



