370 THE ORCHID REVIEW. 
CALENDAR OF OPERATIONS FOR DECEMBER. 
By H. A. BuRBERRY, Highbury, Moor Green, Birmingham. 
THE temperature for the winter months should range as follows :— 
THE Coot House.—Day, with sun, 60°; without sun, 50° to 55°; 
night, 50°; morning, 45° to 50°. 
THE INTERMEDIATE Hovuse.—Day, with sun, 65° to 70°; without sun, 
60°; night, 55° to 60°; morning, 55° to 58°. 
Tue Warm House.—Day, with sun, 70° to 75°; without sun, 65° to 
70°; night, 60° to 65°; morning, 60°. 
The present autumn has, up to the time of writing, been particularly 
foggy, and in large centres of industry the air has been impregnated with 
smoke and various gases, which would otherwise have passed away quickly 
into space, and thus the atmosphere has been rendered more or less dis- 
tasteful to vegetable life. Some species are, of course, more sensitive in 
this respect than others; but generally speaking the flowers of all become 
affected in a greater or lesser degree, whilst the foliage of some also soon 
indicates its objection to atmospheric impurities by turning yellow and 
falling off. I have noticed this most particularly with some of the Mexican 
species, such as Epidendrum vitellinum and Lzlia autumnalis. It is, 
unfortunately, an ill which must be endured, and the only way to avoid 
extremes in this matter of loss of foliage that I can suggest is to keep up a 
good supply of atmospheric moisture, and admit no air during the times the 
fog ison. Now that we are in the depth of the dull season it is more than 
ever necessary to be carefulin such matters as watering, ventilating, and pay- 
ing constant attention’to the maintenance of the most suitable atmosphere. 
Of course, no good cultivator will try to force his plants to make growth 
quickly at this dull dark season ; but ‘will endeavour by all possible means 
to prevent them from going back. This can be done only by keeping up 
the above-mentioned temperatures steadily, avoiding éxcessive heat or cold, 
moisture or aridity. Of the two latter I believe aridity is the most injurious 
when carried to extremes, either at the roots or in the air. It should be 
seen that the resting of any Orchid that may be dormant is not too severely 
done, whilst all those that are growing’should be afforded enough water to 
keep the compost in a moistened state. And it will generally be found 
necessary to damp down the floors, &c., once or twice daily, as it may seem 
to require. This will cause the hygrometer to register, if that instrument is 
employed, about three degrees below the temperature, or in other words 
three degrees of evaporation for the greater part of the time, and this 
remark applies to the Cool, Intermediate, and Warm departments ; that is, 
so far as it affects the atmosphere. Where it is possible to collect all the 
cool resting Ccelogynes, Dendrobiums, Lycastes, and some few individual 
members of the genera Odontoglossum and Oncidium and their allies into 
