favou"able for the Gio '^th of Seed, 
49 
•acid and to retain the carbon for its own, whilst the oxy^tm is 
thrown off into the air. But at this earlier stage of existence, or, 
in other words, during the period of germination, growth is 
favoured by an action /</.v< the rnierse of this. The seed and its 
sprouts want to absorb, not to throw off oxygen, and to emit 
instead of taking in carbonic acid. During germination, then, 
the action of light would tend to paralyse the vital powers of the 
seed, and limit its growth to the hours of darkness, instead of 
allowing the development to be continuous. Another great 
atlvantage gained by covering the seed is the more equable 
supply of moisture which is preserved beneath the surface, as 
well as the better opportunity afforded to the roots for firmly 
fixing themselves in the soil. 
After this hasty glance at the general principles involved in 
the germination of seeds, we may proceed to notice the special 
requirements of the various crops which come under the care of 
the agriculturist, and to describe the preparation of the land 
which is most successfully adopted in each case. It may be 
as well for me to remark, that although the composition of the 
soil is an essential point in the preparation made for each crop, 
yet it does not come within the scope of this Essay to notice the 
means by which we regulate the presence of those fertilisers 
which are necessary for luxuriant growth. 
Wheat. — The mode of preparing land for being sown with 
wheat will be regulated by the previous cultivation it may have 
received and the natural character of the soil. The heaviest 
clay soils are generally prepared by bare fallow : this plan being 
found, in the majority of cases, productive of the best crops of 
corn from this description of land. When this plan is properly 
carried out, the tillage which the field receives brings it into a 
nice condition for the seed-wheat to make its growth. Close and 
adhesive as these soils naturally are, it has been found necessary 
to adopt a method of cultivation by which the character of the 
soil shall become thoroughly changed. Under the action of a 
properly-managed fallow the soil becomes broken up by the frosts, 
baked by the sun's rays, and crumbled again by the fall of rain ; 
and these influences, combined with the inversion and inter- 
mixing effected by implements employed upon the land, change 
it from being close and adhesive In its character into the con- 
dition of a well-broken soil fitted for the growth of seed. 
There Is much difference even amongst heavy clays as to the 
degree of fineness to which it is desirable to reduce the soil whilst 
under fallow ; but the general feeling is that the soil should not 
be rolled, so as to bring it into a fine state, unless the land is foul 
and it Is necessary to give the seeds of any weeds which may be 
in the soil a better opportunity of growth. Even then it is 
VOL. XXI. " E 
