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would even prove superior to the others; yet on the whole, we 
must give a much greater amount of importance to the glazed 
covers ; nevertheless, there should, doubtless, be a set of each 
in every gardening establishment ; for the opaque covers, in 
many cases, would forward crops for the glazed ones, the latter, 
perhaps, being all engaged at the time. 
In preparing ground to receive the drill covers, some special 
culture will be necessary, of which more shall be said by and 
bye. It will not be improper, however, to observe here, that as 
the sides of our drill covers are but six inches (and it being 
only nine inches to the apex from the ground level perpendicu- 
larly) a little ingenuity will be requisite in forming the plot to 
receive them ; we name this by the way, in order to anticipate 
an objection which might be raised, of their being short of 
depth. We can show in the sequel how the objection can be 
shorn of its weight ; our intentions in planning them thus shal- 
low, were merely to render them as portable as possible, and to 
economise expense. 
Before concluding with the drill covers, we must say a few 
words about the ventilation of those which are glazed. Whe- 
ther they should have much or little glass, depends, of course, 
in some degree, on the strictness of economy with which they 
are made. As a matter of principle we should say that it would 
be well to have the whole of the span roof glazed; the sides 
and ends, of course, being of wood, for lightness and economy’s 
sake. If this plan be adopted, we do not see why the whole of 
each side of the roof should not open to ventilate the interior. 
It is, nevertheless, only of second-rate import to have these 
arrangements so carried out ; we may merely say that a copi- 
ous ventilation must be provided ; and that no doubt many of 
our readers are in a position, equally qualified with ourselves, 
to carry out such results. 
It may here be observed that, whatever the mode of venti- 
lation may be, it is essential that the flaps or ventilating portion 
open upwards from the shoulders of the drill covers towards 
the apex ; in fact, in a similar way to that suggested for 
the opaque drill covers. This will prevent the injurious effects 
of hail storms, and of cutting winds ; and moreover will be 
found of immense benefit, under the course of culture here pro- 
posed, in warding off the perpendicularly acting white frosts in 
