224 HEATING AS APPLIED IN HORTICULTURE. 



and Healy. Here, again, the roof of the 

 stove is objectionable, being formed of 



Fig. 303. 



plates of metal made into compartments, 

 with grooves to be filled with sand to 

 prevent gaseous exhalations. It is con- 

 structed in separate pieces, to prevent 

 fracture by unequal expansion. A fire- 

 brick arch would have answered the pur- 

 pose better, so far as the purchaser at 

 least is concerned. 



There can be no doubt of the purity of 

 intention of both Mr Murray and Mr 

 Meek — both since deceased 1 ; the one the 

 imaginary inventor, and the other the 

 staunch advocate, of this mode of heating. 

 It is, however, to be regretted that, in 

 canvassing the merits of the principle, so 

 much ill feeling has prevailed, — and con- 

 sequently error and prejudice have been 

 promulgated, truths have been perverted, 

 and assertions made which had not even 

 the appearance of probability to support 

 them. As a useful mode of heating, our 

 own opinion is unfavourable to it ; and 

 we think, had it been designated the 

 Polmaise mode of ventilating, rather than 

 of heating, the title would have been 

 more appropriate. What success may 

 have attended its adoption in the south, 

 we know only by report this much, 

 however, we do know, that its utility in 

 the north has not been very great ; and, 

 so far as we are aware, there are very few 

 exemplifications of it even up to this time 

 in Scotland. Even with regard to its 

 success at Polmaise— in the neighbour- 

 hood of which, by-the-by, a few years 

 ago, grapes ripened in the open air — we 

 know that the grapes sent to Edinburgh 

 for competition in September were scarcely 



ripe, although otherwise good- sized fruit, 

 such as might be expected from vines 

 producing from one to three bunches each, 

 and that for the sole purpose of exhibition. 

 Its applications in England, so far as we 

 are aware, have been upon so small a 

 scale, that we can attach but little im- 

 portance to the published results. 



Hazard's plan of heating is thus de- 

 scribed by him in a communication 

 to " The Gardeners' Chronicle : " — " I 

 send a sketch of a range of garden 

 houses — fig. 304 section, and fig. 305 



ground-plan — heated under my direc- 

 tions, comprising a forcing-house 30 feet 



long, and green- 

 house 16 feet long, 

 both 14 feet wide ; 

 and two melon pits, 

 each 8 feet square. 

 The apparatus for 

 warming the whole 

 of these, contain- 

 ing, independent of 

 bottom heat, an 

 area of upwards of 8000 cubic feet, con- 

 sists of a fire-box k, 18 inches by 16 

 inches, connected with the smoke-flue by 

 a series of five rows of tubes, five tubes in 

 each row. The heated gases produced by 

 the combustion of the fuel traverse the 

 whole of these pipes, affording a radiating 

 surface of 200 superficial feet. The sup- 

 ply of fresh air is brought from /, and 



