33? THE ORCHID REVIEW. [NovEMBER, 1915 
The injurious effects of artificial heat during unusually cold weather, 
‘when the hot-water pipes have to be kept extra warm, should be as far as 
possible counterbalanced by the admission of fresh air, and the use of a 
moderate amount of water in damping the paths, stages, and immediately 
under the pipes, thus moderating the dryness of the air in the house. In 
order to economise heat during spells of cold frosty weather, it is good 
practice to cover the houses with canvas, garden mats, &c. The mats 
should be neatly and strongly tied at the ends, and several may be sewn 
together in different lengths as required for each house. These may easily 
be rolled along the lower part of the roof, which is generally the coldest 
part of the house, putting them on at dusk and taking them off at day- 
break. As a safeguard in cold windy weather, these coverings should be 
made secure, so that they cannot be blown off, and when wet or frozen 
they should be thoroughly dried before using them again. Some growers 
leave their open lattice wood blinds on all the winter, in order that when 
cold nights come they may be let down over the glass, also over the mats, 
which not only assists to keep them firmly fixed in their places, but are a 
great help in keeping up the temperature of the house. It is not advisable 
to employ the usual canvas roller blinds for this purpose—although they too 
are useful in maintaining the warmth inside—for it may happen in very cold 
weather that they become frozen so stiff that they cannot be rolled up 
again for several hours after day-break, the plants thus losing a considerable 
amount of light which, as previously mentioned, is an agent they never get 
enough of during our long dull winters. : 
If there be any large deciduous trees near to the Orchid houses, they 
will probably, ere this, have discarded their foliage, and immediately the 
leaves have fallen, the glass of the houses, both inside and out, should be 
well washed, and at the same time see that all the laps in the glass are also 
freed from dirt, for when these Japs are thoroughly clean more air can 
penetrate, thus causing a nice refreshing feeling in the atmosphere inside. 
The woodwork should likewise be scrubbed, and if the walls are lime- 
washed, it will greatly assist in increasing the light in the houses. | While 
the plants are being removed and re-arranged they should all be carefully 
examined for insects. Sponge the leaves with clean soft water, wash the 
pots, stages, &c., and keep everything about the plants trim, clean, and 
tidy. In ventilating the houses through the winter months the aim should 
be to admit as much fresh air as possible without chilling the plants. In 
low-roofed houses this is best done by opening those ventilators on the 
ground line, and these should be near, or opposite to the hot-water pipes. 
In mild weather the top ventilators in lofty houses may be opened slightly, 
there being less danger here of the plants getting chilled. When very cold 
or east winds prevail it is best to keep the top lights closed, and to regulate 
