On the Drill Huxbandry of Tvrnips. 
57 
simple reflection, that of course it could not fj^row where it was 
entirely out of reach of the circulation of air, and that the same 
absence of air which ])revented seed from vejj^etating, mif^ht still 
tend to preserve its veyctatiinj quality, until brought under more 
favourable circumstances for calling it into action, I at once 
came to the conclusion that, if I cultivated the land so as to cause 
all the seed to grow that was within the circulation of the air, or 
usual ploughing depth, and, after the seed had grown, destroyed 
the weeds by ploughing the land, I should by that means get rid 
of all cause for apprehension on their account until I ploughed 
deeper. I therefore invariably acted on this idea, experience 
convincing me of its correctness ; and I can now say that, under 
favourable circumstances of the turnip-fallow season, for getting 
the seed grown, it is a most effectual remedy. 
In the summer of 1830 a most favourable opportunity pre- 
sented itself for putting my theory to the test. One of the fields 
I had to sow with turnips that season had always been much 
subject to growing charlock, therefore I determined to make the 
whole of the seed, within the depth of the first ploughing, grow, 
and, having grown, to destroy it of course before the time I wished 
to sow the turnips. 
The first ploughing was done early in the autumn, as I have 
before recommended. The next in the first period after Christ- 
mas, in which the land seemed sufficiently dry for the purpose ; 
this was of course across the other, it being well known that on 
light soils with dry substrata, it is better that each succeeding 
ploughing, or dragging, should be taken in a contrary direction 
from the preceding one. In a short time the land became suffi- 
ciently dry to harrow and roll ; it was therefore immediately har- 
rowed with common harrows, closely followed by the drag-iiarrow 
with its broad set of teeth, there being no couch in the land ; 
then alternately harrowed and rolled, each operation following as 
closely on the other as practicable, until the soil was as thoroughly 
pulverized as possible, so that the seeds of the weeds might thus 
be more likely to grow. 
After a few days the charlock sprung up so thickly, as nearly to 
cover the whole surface of the land. I allowed it to grow to 
about 2 inches in length, and then had the land again dragged 
with the drag-harrow as before, the common harrows and roller 
again following each other as closely as possible ; and the field was 
soon prepared for a second crop of charlock. A second certainly 
soon came, but it was a very thin one in comparison with the 
first ; I had evidently caused the greater part of the seed to grow 
at once. 
This process was repeated for the third lime, the crop of char- 
lock still diminishing ; and when, after the fourth v^orking, I sowed 
