238 REMARKS, 
vigour. Again, plants, natives of a colder climate, may be grown in 
a far warmer one than ever they were subjected to in their natural 
state, provided at all times the extra heat and moisture are judicicusly 
applied, and only when the plants are in full vigour and in good health ; 
so we find that air plants, although naturally subjected to a high 
temperature, may, with proper precautions, be grown with advantage 
in a much lower one; and as all plants grown in a lower temperature 
than their natural one require less moisture, so Orchids, in a cool 
atmosphere, should be kept drier during a certain period of the year ; 
an increase of moisture should only be given with an increase of heat, 
and that only in the growing season. It should be recollected that no 
plants can exist for any very great length of time without rest, and 
that rest is induced in a tropical climate by drought, in the same way 
as low temperature in our own country suspends vital energy: there- 
fore Orchids must be subjected to the usual seasonable changes of rest 
and activity. Rest is induced by withholding moisture from their 
roots, and partly from the air, and this state of things may be consi- 
dered to represent their winter. Spring should be imitated by gradually 
reviving energy, by inerease of moisture, first to the atmosphere, and 
afterwards to the roots or soil, accompanied by a proportionate increase 
of temperature: this period of their growth should be very slow. 
Summer must be represented by a greater increase of both heat and 
moisture; partial shade should also be resorted to to bring the energy 
of the plant into full foree. And lastly, an autumn must be created to 
bring about maturity by gradually reducing the quantity of both heat 
and moisture, until the plants are again brought to a fit state for repose. 
The first and last stages should be of but short duration, and require 
caution, otherwise much mischief may be done to the plants. By 
growing Orchids in the mean instead of maximum of heat and moisture, 
they will not make such rapid growth; but they will become more 
robust and healthy, and be less liable to receive injury from sudden 
transitions in the atmosphere, either of heat, drought, or moisture. 
The temperature of the house can only with certainty be kept regular 
by night, particularly in summer ; therefore the fire should never raise 
the heat of the principal house higher than 60°, and about 5° less 
should be maintained where the plants are in a less excitable state ; 
but as the days lengthen, so the temperature may rise, yet it should, 
if possible, never range higher than 75° by night in summer; it will 
occasionally, however, be higher in very warm weather, and should be 
counteracted as much as possible by evaporation and ventilation by 
night, and by both, as well as by shading, by day. Injury is often 
effected by a sudden rise of temperature by ’fire-heat in winter, while 
little or none is caused if the rise is occasioned by sun-heat: care 
should therefore be taken to guard against a rise of temperature by 
fire-heat, particularly in midwinter; rather suffer a depression of a few 
degrees of heat in very severe weather than use over-strong fires, 
which will over-dry the atmosphere, and, on the other hand, create too 
much moisture, if water is supplied. Moisture, however, is by no 
means injurious to Orchids, provided they can part with it freely, but 
they are impatient of stagnant damp.—Mr. Gordon’s Paper in the 
Journal of the Hort. Society. 
