its particles adhering together in the familiar 
form of mud.—Turning our eyes to jig. 4, we 
observe still another condition of soil; in this in- 
stance, as far as water is concerned, the soil is in 
its healthy condition—it is moist, but not wet— 
the pores alone being filled with water. But where 
are the canals? We see them in a few places, 
but in by far the greater part of the soil none 
are to be perceived; this is owing to the particles 
of soil having adhered together, and thus so far 
obliterated the interstitial canals that they ap- 
pear only like pores. This is the state of matters 
in every clod of earth 4; and you will at once 
perceive, on comparing it with c, which repre- 
sents a stone, that these two differ only in pos- 
sessing a few pores; which latter, while they 
may form a reservoir for moisture, can never act 
as vehicles for the food of plants, as the roots 
are not capable of extending their fibres into 
the interior of a clod, but are at all times con- 
fined to the interstitial canals. 
“ With these four conditions before us, let us 
endeavour to apply them practically, to ascertain 
when they occur in our fields, and how those 
which are injurious may be obviated. ‘The first 
of them, we perceive, is a state of too great dry- 
ness, a very rare condition, in this climate at 
least ; in fact, the only case in which it is likely 
to occur is in very coarse sands, where the soil, 
being chiefly made up of pure sand and particles 
of flinty matter, contains comparatively much 
fewer pores; and, from the larger size of the 
individual particles, assisted by their irregularity, 
the canals are wider, the circulation of air freer, 
and consequently the whole is much more easily 
dried. When this state of matters exists, the 
best treatment is to leave all the stones which 
occur on the surface of the field, as they act as 
shades, and thereby prevent or retard the eva- 
poration of the water. We will not, however, 
make any further observations on this very rare 
case, but will rather proceed to jig. 2, a much 
more frequent, and, in every respect, more im- 
portant condition of soil,—I refer to an ex- 
cess of water. When water is added to per- 
fectly dry soil, it of course, in the first instance, 
fills the interstitial canals, and from these enters 
the pores of each particle ; and, if the supply of 
water be not too great, the canals speedily be- 
come empty, so that the whole of the fluid is 
taken up by the pores; this, we have already 
SOWING. 
ever, the supply of water be too great, as is the | 
case when a spring gains admission into the soil, 
or when the sinking of the fluid through the 
canals to a sufficient depth below the surface is 
prevented, it is clear that these also must get 
filled with water so soon as the pores have be- 
come saturated. This, then, is the condition of 
undrained soil. Not only are the pores filled, 
but the interstitial canals are likewise full, and 
the consequence is, that the whole process of the 
germination and growth of vegetables is ma- 
terially interfered with. Of course all the in- 
jurious effects are at once overcome by thorough- 
draining, the result of which is to establish a 
direct communication between the interstitial 
canals and the drains, by which means it follows, 
that no water can remain any length of time in 
these canals without, by its gravitation, finding 
its way into the drains.—The fourth figure in- 
dicates badly cultivated soil, or soil in which 
large unbroken clods exist. Too much cannot be 
said in favour of pulverizing the soil; even 
thorough-draining itself will not supersede the 
necessity of performing this most necessary opera- 
tion. The whole valuable effects of ploughing, 
harrowing, grubbing, &c., may be reduced to 
this; and almost the whole superiority of garden 
over field produce is referable to the greater per- 
fection to which this pulverizing of the soil can 
be carried. The whole success of the drill hus- 
bandry is owing, in a great measure, to its ena- 
bling you to stir up the soil well during the pro- 
gress of your crop; which stirring up is of no 
value beyond its effect in more minutely pul- 
verizing the soil, and increasing, as far as pos- 
sible, the size and number of the interstitial 
canals. Lest any one should suppose that the 
contents of these interstitial canals must be so 
minute that their whole amount can be of but 
little consequence, I may here notice the fact, 
that in moderately well pulverized soil they 
amount to no less than one-fourth of the whole 
bulk of the soil itself. For example, 100 cubic 
inches of moist soil (that is, of soil in which the 
pores are filled with water while the canals are 
filled with air) contain no less than 25 cubic 
inches of air. According to this calculation, in 
a field pulverized to the depth of 8 inches, a 
depth perfectly attainable on most soils by care- 
ful tillage, every imperial acre will retain be- 
neath its surface no less than 12,545,280 cubic 
inches of air. Taking into the calculation the 
weight of soil, we shall find that, with every ad- 
ditional inch which you reduce to powder (by 
ploughing, for example, 9 inches in place of 8), 
you call into activity 235% tons of soil, and ren- 
der it capable of retaining beneath its surface’ 
1,568,160 additional cubic inches of air. And to 
take one more element into the calculation, sup- 
posing the soil were not properly drained, the suf- 
ficient pulverizing of an additional inch in depth 
would increase the escape of water from the sur- 
seen, is the healthy condition of soil. If, how- ) face by upwards of 100 gallons a day, a quantity 
