BOTTOM HEAT. 
107 
certain that, during every process of decay — (the result of fermentation) — 
agencies of prodigious power are exerted : water is decomposed, a galvanic energy 
is displayed in the progressive development of the elements oxygen, hydrogen, 
nitrogen, and in new combinations, forming hydro-carbons, carbonic acid, 
ammonia, &c, all essential to vegetation ; and these facts, which now are placed 
beyond reasonable doubt, tend to repudiate the opinion that the efficiency of 
bottom-heat is dependent solely upon increase of temperature. In a word, we may 
safely infer that the process of radification is the result of electro-chemical 
attraction, while that depends upon elemental disturbance. 
So far, it will be evident that we are constrained to favour the old fermenting 
medium ; but, alive as we must be to its inconveniences, we inquire whether the 
new and cleanly bed resting over the tank would not suffice for all the processes of 
propagation, and also to maintain the ample verdure and health of such rooted 
plants — as for instance, the Gardenias — which demand the appliance of moist and 
warm substances to the surface of their pots ? Were charcoal- powder always 
employed, with sand sufficient to give it texture and firmness, we have little doubt 
that the roots would emerge, and revel in the bed ; and no scalding or burning 
would result from the violent extrication of ammoniacal gases. And although in 
the event of protruded roots, the luxuriance of vegetation might not equal that 
produced by the tan or leaf bed, yet not only do gardeners object to this rooting 
for the reasons before assigned, but they ought on every account to prefer cleanness 
and security, provided they are not purchased at the expense of a positive injury. 
A tank alone will not be sufficient for hothouse or even pit culture ; we must 
have atmospheric moisture and heat; therefore from the returning channel or 
gutter of the tank a connected pair must be continued in front, by the end, and 
generally at the back of the erection, so as to convey the flow- water ; and a cor- 
responding " return " stream, till the latter terminate in the receiving pipe of the 
boiler ; and then, if these channels be regulated by sluices across the watercourse, 
and by sliders at the top, both correctly adapted and moveable, any degree of 
moisture may be commanded and regulated. 
We now invite our intelligent readers to observe, and decide for themselves, 
for such are the conveniences of the hot-water tank-plunging system, that we 
should regret extremely to see it abandoned for one which, for years, has been 
productive of nuisances of the most serious character, A further remark, and that 
a painful one, remains to be made ; the vapour of a tank-house is not found to bear 
out the assertion that it will afford ample protection against the Acarus, or plant- 
spider. We have very lately seen an entire collection of Gardenias the prey to 
thousands of this pest ; and now, as sulphur also is found utterly valueless, we 
fear that there is no remedial application, and that the gardener must trust to 
vigilance alone, 
