ON THE CULTURE OF THE CUCUMBER. 
47 
labour, and filth, and uncertainty, which is attendant on the use 
of casings of fermenting material, as a'means of maintaining a 
requisite degree of heat: when we consider the advantage of 
being able to bestow that degree of attention to the plants which 
they require, without exposing them to the influence of a rush 
of cold air, as is the case when the lights of a frame or pit are 
opened, we have quite enough before us to establish the pre¬ 
ference of a small house over a dung-bed, and moreover, over a 
pit, even though the temperature of this latter is maintained by 
means of a hot-water apparatus. Neatness, economy, conve¬ 
nience, and certainty, are the advantages gained by employing 
a pit so heated, over that of using a structure in which the tem¬ 
perature is maintained by the aid of fermenting masses ; whilst 
a still greater degree of certainty, and also of convenience, are 
the particulars in which small houses may be regarded as being 
preferable even over pits. 
With regard to the question of heating, the gutter and the 
tank system are both valuable, the latter especially, as a means 
of securing an equal and genial degree of warmth to the roots. 
With the use of fermenting masses they admit of no comparison 
whatever, being infinitely preferable. It must not, however, be 
supposed, that the heat thus conveyed to the atmosphere, is in 
itself more suited to the plants to which it is applied, than that 1 
supplied by other means,—for heat, that is, simply caloric, is the 
same in its effects whatever may be the source through which 
it is derived; and consequently, heat imparted from fermenting 
manure is as good for the purpose as that derived directly from 
fire through the medium of a body of water ; in one sense, it is 
even preferable, for ammonia, combined with other gaseous 
bodies, is contained in the vapour of fermenting manure, and this 
ammonia is of considerable value to plants when it does not exist 
in excess. The value and importance of the tank system con¬ 
sist in the uniformity of its action ; for when once heated, a 
body of water such as that employed is found to maintain, with 
little trouble, and by the application of very slight stimulating 
power, a constant and genial degree of warmth ; whilst, on the 
other hand, fermenting masses are, from their very nature, both 
fluctuating and ephemeral in their action ; and, setting aside 
altogether the labour attendant on the employment of them, we 
have at once before us, in this particular, a proof of tneir decided 
inferiority to the tank. Cultivators know full well that in 
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