266 TRANSACTIONS OF THE 



The chemical effect produced by pulverizing the soil is in two ways ad- 

 vantageous ; it enables the roots to penetrate to a proper depth, and renders 

 it permeable by atmospheric influence, thus supplying the roots with oxy- 

 gen gas, and moisture, not only from the soil, but atmosphere. This power 

 to absorb moisture from the air depends upon the division of the particles 

 of soil, their absorbing powers increasing in proportion to the disintegra- 

 tion ; when this power is great, moisture is abundantly supplied even during 

 drought. The most fertile and highly cultivated soils possess the greatest 

 absorbent powers. An imperfectly pulverized soil invariably exposes a 

 large surface to the wind and sun, which of course facilitates by evapora- 

 tion the loss of moisture, and directly aggravates the injurious influence of 

 drought, in every stage of the growth of plants. 



We have seen, then, that to insure the growth of the seeds we place in 

 the earth, a proper cultivation of the soil is of the most importance, and 

 that minute pulverization is indispensable to admit air, and drainage to 

 remove superfluous water, which would otherwise destroy the seed. 



The next important step is sowing the seed, and although they will vege- 

 tate in a moist atmosphere on the surface of the earth, and also even when 

 too deeply covered, it does not certainly follow that the depth at which 

 they are planted is unimportant ; too much covering is very detrimental, 

 and entirely at variance with the wonderful process of nature. You will 



observe on the black board 



/ / two rye plants ; a represents 



a seed planted at the proper 



distance below the surface of 



the earth, and b one that was 



^-^ / \^"^^ /^ /'\^^^^ — *oo deeply covered ; h vege- 



^ ^ •' tated notwithstanding the 



mistake in planting, and 

 threw out two sickly leaves 

 above the ground, where they 

 remained stationary until 

 new roots were formed near the surface superseding the first. While a 

 being properly planted far surpassed h. Those practising the drill system 

 find that seeds can be more uniformly planted than when sown broadcast 

 promiscuously and harrowed in ; and should therefore be generally prac- 

 ticed in all expedient cases. 



The most critical period in the life of a plant appears to be, when the 

 seed has completely expended its nourishment in its development, as may 

 be detected, by the yellow appearance presented by it, immediately after 

 being weaned, and left to seek in the earth a new kind of food. At this 

 period all sickly individuals die, and by their decomposition strengthen and 

 invigorate the healthy advancement of the rest, which progress rapidly 

 to maturity, if the disintegration of the earth has been thorough. The inju- 

 rious consetjuences of the often extreme variations of seasons are mitigated 

 when the land is thoroughly and perfectly drained, and cultivated with 



