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 
