34 
GARDENING AS A SCIENCE. 
and cheap boiler, which consists of two small copper cylinders, one within the 
other, the exterior vessel containing the water, the inner cylinder the fuel, (coke or 
charcoal,) which thus, being in contact with every inch of the former, produces the 
full effect, equably and speedily. As we have not inspected the machinery, we 
can only allude to it as an improvement upon a previously-announced discovery, 
whereby any person can possess himself of a hot-water apparatus for a mere trifle, 
and " maintain it for twenty-four hours in action at the expense of two-pence I" If 
this be true, the invention is worthy of support ; but our own experience of fire- 
work may serve to render it (and any other contrivance) more economical by the use 
of Moira coal — both large and small ; no material, that we are aware of, is, in fact, 
so appropriate : it consumes entirely to a white ash, rarely clinkers, and never deserts 
the fireman. If Newcastle or Bath coal cost two-pence per night, an observant and 
adroit person will effect the same operations for three-halfpence, by the use of the 
Moira ! Mention has been already made of this new combustible, but we re-urge 
its use from the conviction of its value, which every day's experience tends to confirm. 
Solar light, though it produce intense yet ever-varying degrees of heat within 
a glazed erection, is not in any degree similar to the heat radiated from a flue in 
the hours of darkness. The conviction of this truth has led to very opposing con- 
clusions. Some, and the greater number, of routine gardeners, advocate the necessity 
of maintaining high temperature by night, in order to obviate the danger of arresting 
the growth of their plants by what they term a check ; but others, men of inquiring- 
minds, who take a philosophical view of the phenomena of nature, have argued that 
a high temperature during darkness is at variance with the natural laws, and can in 
no instance be justified by correct analogy. The late President of the Horticultural 
Society, Mr. Knight, may be regarded as the leading authority in this reform of 
the theory of forcing ; and a writer of an article which appeared in col. i. p. 54 of 
the Gardeners Chronicle of January 28th, has detailed some facts confirmatory of 
that theory. 
Taking the Vine as his subject, he states, that his standard of fire heat, 75^ 
allowing himself a range of 3" above and below that point, had produced " the 
development of weak, long-jointed wood — fruitful, certainly ; the fruit, however, 
like the wood, being weak, the branches long and straggling, the berries small, 
and, when ripe, very imperfectly coloured, and in many cases shanking off." A 
practical friend called, and upon inspecting the vines and the state of the fruit, 
then changing colour, and hearing from the grower the detail of his practice, 
adduced a variety of arguments, and suggested the following regulation : — " Begin 
with a temperature lower than 50°, increase it gradually, and always let it at 
night sink at least 10° lower than what you consider necessary by day." Complete 
success followed ; and " strong, short-jointed wood, and close, compact, finely- 
coloured branches," resulted in two seasons from attention to the advice given. 
Low, night temperature may, we admit, offend some delicate tropical subjects ; 
it may also check a pine-apple plant, which naturally revels in low, vaporous, 
