TRAILING PLANTS, AND THEIR CULTURE. 
233 
A further rule in putting on fire-heat to a house, is to have the apparatus 
always ready for working, and not to get up the temperature so suddenly, nor to 
so great a height, as is often done in urgent circumstances. A violent transition 
from cold to extreme heat is exceedingly injurious. 
Some of the modern modes of heating consist of open gutters in the house, 
along vs^hich the water that is to warm it flows. It is hardly necessary to say 
that, unless some provision exist in them for covering in the water- channels at 
pleasure, the employment of these in winter violates all our principles of genuine 
economy, as respects both the amount of fuel demanded, and the effect on the plants. 
The last, and undoubtedly not the least efficient plan of economizing fire-heat, 
to which we intend now adverting, is by putting on an outside covering to the 
glazed portion of a structure. With something of this kind that is really effectual, 
fires will be altogether needless in greenhouses, and the expense of even an heating 
apparatus will be saved. Considering the great economy and advantage of the 
plan, it is singular that so few have adopted it. For pits, particularly, it would 
be peculiarly adapted, on account of the greater facility of applying it. Surely a 
little of the ingenuity that is bestowed on less important objects might devise a 
material which would possess none of the objectionable features of those hitherto 
used. Their great fault is, that they are too cumbrous. It appears to us that 
something in the way of the oiled canvass or calico at present substituted for glass 
in garden frames, might be found, when rightly elevated above the glass, to exclude 
an immense deal of cold. 
We fear that we shall expose ourselves to the charge of having over-estimated 
the interest of our subject, by the length to which we have pursued it. It is 
alone, however, as we conceive, by tracking out an inquiry in all its ramifications, 
and, by fixing on one main point, concentrating every variety of evidence and 
argument in the establishment of that, that any decided advance can be made in 
the propagation of correct principles. We will only add, that though we do not, 
without some modification, include stove plants in the remarks we have made, we 
yet believe that, in winter, they need very little beyond shelter ; and that the 
current system of maintaining the stove always warm is totally erroneous, adverse 
to the well-being of the plants, and destructive of the fundamental principles of 
economy. 
TRAILING PLANTS, AND THEIR CULTURE. 
It is a very convenient and useful mode of arranging the vegetable kingdom, 
for the purposes of cultivation, to divide it into great classes, according to fixed and 
prominent peculiarities of habit. Such a method, however, is too little practised ; 
and hence, when any kind of plant is wanted for a particular object, or when a 
VOL. X. NO. CXVIII. H H 
