146 



breaking the lumps left by the plough. Rolling stiff soils 

 when wet, would only make them too hard and compact, 

 and thus do them more harm than good. 



CHAPTER XY. 



SOWING, PLANTING, ETC. 



462. Moisture, warmth, and exposure to the air, to 

 some extent, are needed to make the seeds of plants 

 germinate healthfully. Light is not necessary; on the 

 contrary, it is believed to interfere in some degree with 

 the process of germination. 



468. The seed is buried in a properly prepared soil, 

 where the moisture soon softens it throughout, and certain 

 chemical changes take place, by which the mealy parts 

 are prepared to nourish the swelling germ. 



464. A radical shoot or rootlet first bursts its covering, 

 and invariably grows down, fixing itself in the soil, 

 while a stalk shoots up towards the air and light in which 

 it expands its leaves. 



465. By means of its leaves, which serve as its lungs, 

 the plant draws much nourishment from the air. There 

 arc a great many small openings or pores in the leaves, 

 which are most numerous on the under side. On a 

 single square inch of the leaf of the common lilac, there 

 are no less than, one hundred and twenty thousand of 

 these little mouths, and on an inch of the white lily 

 there are sixty thousand. They are found in great 



