BOTTOM-HEAT FOR ORCHIDS. 
283 
for the assistance of all who feel interested in the matter. As 
my quota, I send you the following outline of the advantages to 
be derived from the employment of bottom-heat in the growth of 
these plants. Its effect on all that have hitherto been subjected 
to its influence is surprisingly beneficial; but, as might reason¬ 
ably have been anticipated, is most evident in the case of Indian 
epiphytes, as instanced through the genera Aerides and Sacco- 
labium. These are vastly improved in every respect,—a greater 
number of roots are protruded, the growth of the foliated parts 
is increased and rendered vigorous, and the subsequent flowering 
made more abundant and highly coloured. 
In fact, I regret only that, owing to the limited space at com¬ 
mand for the purpose, the entire collection has not had an op¬ 
portunity of receiving the benefit which in every case tried has 
resulted. The improvement being so great, I would earnestly 
advise those who have not tried it, to devote a portion of the 
stove to the erection of a bed for the purpose. The exact for¬ 
mation of such an affair must necessarily depend upon the manner 
in which the house is heated, as I would in every case make the 
apparatus which maintains the temperature of the house sub¬ 
servient to this end also, rather than trust to fermenting mate¬ 
rials, for the reason to be subjoined. Here the main dependenee 
is on hot-water tanks, which are every way best suited for orchi¬ 
daceous houses, and afford an easy opportunity of forming a bed 
for the purpose described, all that is required being, to run a slip 
of wood along the back and front edge of the tank, about four 
inches deep, and to fill up the space thus formed with the screen¬ 
ings of coal ashes or small pebbles, these proving the best mate¬ 
rials, on account of their continued porosity, allowing the heat 
’ to rise freely, and at the same time affording the requisite drain¬ 
age to the plants standing thereon. 
Sand, though at first sight promising to be the best medium, 
was found in a little time to become covered with a thick, im¬ 
penetrable coat of the smaller particles, which had become fused 
together, as it were, by the action of the heat and frequent water¬ 
ings ; and I would particularly advise that no bark, or tan, as it 
is called, be used, or any other fermenting material, as in the 
course of a short time they are filled with innumerable insects. 
The plants, when in a growing state, are merely placed upon 
