340 
THE FLORAL WORLD AND GARDEN GUIDE, 
ieated by gas or ordinary fuel, provided the boiler is of a proper 
character. A very large number of amateurs suppose that in heat- 
ing plant houses by gas the gas is burnt in the house ; but notwith- 
standing the fact, that the combustion of the gas is most injurious 
to plant life, has been frequently pointed out in the most prominent 
manner possible, gas heating has considerable advantage, for the 
only attention required is to turn it on and shut it olF as required. 
It can thus be left for an indefinite period without any attention,, 
and on lighting it on the appearance of frost, it will be simply 
necessary to ascertain the force of gas required to keep out the frost, 
and then regulate it accordingly. Gas is more expensive than fuel, 
but in the case of small houses the difference in the cost will hardly 
be appreciable, and the bother of stoking is done away with. Added 
to this, there is no danger of the plants suffering in frosty weather, 
owing to the fire burning out. For large houses gas is too costlv, 
and fuel is preferable. 
Although a hot-water apparatus is unquestionably the best 
means of heating plant houses, it is well the amateur who cannot 
afford its erection should know that the structures may be most 
effectually heated by a flue. The cost of flues, comparatively speaking, 
is very little, and if built properly, so that the smoke cannot find its 
way into the house, they act most efficiently and are perfectly safe. 
In the case of large houses they should extend round the house, but for 
small houses a single flue on one side will suffice. It will not, however, 
be practicable to carry the flue round the house, if there is a door at 
each end, because the rise from the fire to the chimney must be 
gradual and continuous to ensure a good draught. Flues are perhaps 
the most economical, as the brickwork of which they consist is soon 
made hot, and it also retains the heat for a considerable period after 
the fire has gone out. 
With regard to the management of the fires during the winter 
season, there is not much to be said, although it is most important 
to employ fire-heat judiciously. The only occasions upon which fire- 
heat Mill be required are during frosty and damp weather. As 
sudden changes are most injurious to plants of all kinds, the fire 
should on the appearance of frost be started early, and allowed to 
burn gradually, so that the temperature of the house may be main- 
tained at its proper height, without undergoing any appreciable 
change. The usual way of starting a fire on a frosty night is to 
allow the temperature to fall to within a degree or two of the freez- 
ing point, and then light the fire and drive it as fast as possible until 
the glass stands at or about forty-five degrees, and as the tempera- 
ture will continue to rise for some time after the fire is checked, the 
plants will most probably experience a change of not less than 
twenty degrees within an hour or so. This is not only objectionable 
as regards the health of the plants, but it is exceedingly wasteful, for 
it is impossible to drive fire hard without a great loss of heat. The 
temperature will of necessity decline considerably towards the morning, 
and some degree of caution is necessary in starting the fire. Should 
the weather be bright, no more fire-heat than is absolutely necessary 
to keep out the frost should be employed, for if a huge fire is piade 
