PROTECTION OF PLANTS FROM FROST. 
39 
effective manner. Coverings of bast mats are the most usual, and, 
at the same time most objectionable method; objectionable be¬ 
cause they are expensive without being durable, cumbrous and 
untidy, ineffective, and excessively troublesome in either wet or 
windy weather. * Nor are the best of the other modes in use en¬ 
tirely free from the same or similar objections ; a demurrer of the 
strongest nature may certainly be entered against all loose cover¬ 
ings ; every house, pit, or even common frames where they can 
be ranged in parallel rows, should have a fixed roller on which a 
waterproof covering of some kind may be made to work, so that 
the whole may be covered, or the protection removed with the 
least trouble in the smallest space of time. A cheap, durable, 
pliant, and transparent material, that will exclude frost and wet 
is yet a desideratum. But we have only to state our wants dis¬ 
tinctly, in this age of skill and enterprise, in order to have them 
supplied, so that we do not despair of the arrival of that time 
when mats and other coverings of a similar kind shall be in the 
position that the old brick flues as a mode of heating are fast 
arriving at—mere matter of history. As it is, we have to con¬ 
sider the best manner of using the means we already possess; 
and here we would beg to impress in the most forcible manner 
on the attention of all concerned, the fact that coverings, of 
whatever nature, have their effectiveness increased nearly one 
half by being kept at a proper distance from the surface to be 
guarded; this applies to all glazed structures, the coverings to 
which (and every house or pit should have one, as a means of 
economizing the heat) ought to be elevated three inches above the 
rafters, which may be easily and neatly done by fixing small iron 
rods on feet along the middle of each rafter, on which the roller 
of the blind will run ; and if the covering be a close impervious 
material, such as is offered by waterproof cloths, the space thus 
formed will become warmed by the radiated heat from below, and 
act as a non-conducting medium, in effect nearly equal to the 
same space actually filled with ordinary mats. 
The protection of plants a few grades more tender than com¬ 
mon shrubs, which are ordinarily placed out of doors as perma¬ 
nent objects, will also require attention through this and the fol¬ 
lowing month, and indeed not unfrequently till the middle of 
April. Here, too, an error prevails in practice ; the plants are 
