Ellis's Discourse on HoiiicuUiire. 451 



temperature it aflfbrds, and in the ready means of increasing or diminisliing 

 that temperature, according to the varying progress of vegetation and the 

 fluctuating conditions of the external air. In the second place, security 

 against partial, irregular, and insufficient heating, freedom from offensive 

 and noxious emanations, and easy means of preserving the atmosphere, as 

 nearly as may be in its natural state of purity and moisture, are desirable. 

 And if, in the third place, economy in the construction of the building, and 

 of labour and fuel in conducting the heating process, can be combined with 

 the other more essential conditions above mentioned, the system which 

 unites these advantages in the greatest perfection will doubtless be entitled 

 to a preference. 



" No one, we think, who compares the method of heating by steam, as 

 detailed in the foregoing pages, with that by smoke flues, as ordinarily 

 practised, or with that derived from the putrefactive fermentation of vege- 

 table matters, can hesitate to admit, that, in almost all the requisites above 

 mentioned, it is greatly entitled to a preference ; while it is subject to few 

 or none of the inconveniences and disadvantages to which the latter 

 methods are exposed. In regard to trouble in attendance, and diminution 

 of expense in labour and fuel, the plan of Mr. Hay seems to have accom- 

 plished almost all that can be desired. It may still, however, receive im- 

 provement in some of its details; for, on comparing, as he says, the pits at 

 Cunnoquhie with those at Castle Semple, it will be seen, from the statement 

 of Mr. Smith, that, at the former place, a pit 50 ft. long requires as many 

 hours of steam, in every twenty-four hours, to raise the temperature to the 

 height required, as another 60 ft. long, and nearly a foot broader, does, at 

 the latter place, in every forty-eight hours. ' The reason of this difference 

 is,' says Mr. Hay, * that the pit at Cunnoquhie has only two feet depth of 

 stones, while that at Castle Semple has three feet ;' — a fact which illustrates 

 in a very striking manner the power of the stones to receive, retain, and 

 slowly impart heat." 



It certainly would appear that this mode of heating a bed of stones is far 

 preferable to the mode of heating by hot water, at least for pine culture ; 

 unless an immense cistern of water were substituted for the bed of stones : 

 but such a cistern we consider objectionable on many accounts ; and even 

 if it were not objectionable, we question its power of retaining a sufficient 

 degree of heat for an equal period with a bed of stones, which, though 

 they give out heat faster, yet have more. We request the practical gar- 

 dener to mark the important fact above quoted, that steam only requires to 

 be applied to the pit about one hour and a half in twenty-four during 

 winter, and only once or twice a week in spring and autumn. No system of 

 heating by hot water, that we have heard of, has ever equalled this, in 

 diminishing the labour of attendance and the risk of a failure of heat. 



We participate in the satisfaction which Mr. Hay must enjoy, after a long 

 life assiduously spent in horticultural pursuits, in being the author of such 

 a useful invention. It appears that Mr. Hay applied steam to forcing- 

 houses at Preston in Midlothian, in 1794; and he may now be considered 

 as having perfected this mode of heating. The Caledonian Horticultural 

 Society unanimousl}' awarded him the London medal for 1828; which is 

 something, though the consciousness of the impression which he has made 

 on tlie horticulture of his time, and of being the most eminent horticul- 

 tural architect that Scotland has ever produced, must be his greatest and 

 best reward. 



The mode of heating by hot water is next described, and notice taken of 

 a house, 60 ft. long, in the Society's experimental garden, and of the houses 

 at Woburn Abbey, so heated. After shortly reviewing the modes of heat- 

 ing by smoke flues, by steam, and by the circulation of hot water, and 

 bearing testimony to the great merits of the latter mode, Mr. Ellis con- 

 cludes : — "It seems doubtful, how^ever, whether, in economy of fuel, cspe- 



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