GENERAL PRINCIPLES. 



131 



the economy of heat is concerned, such a 

 circulation should be adopted as would 

 cause a great portion of the heated air 

 at the top of the house to descend to the 

 floor, or under it, to become amalgamated 

 with fresh air from without, and so keep 

 up an ascending and descending current. 

 By the application of mechanical power, 

 the heated air at the top might be drawn 

 down to air-chambers under the floor, 

 through tubes fixed to the under sides of 

 the rafters or curvilinear ribs that form 

 the structure ; and also a supply of cold 

 air could be made to ascend through 

 similar tubes, and be made to diffuse 

 itself at any height or heights that may 

 be deemed necessary. At all events, 

 insufficient ventilation has hitherto been 

 the great defect of extra lofty houses." 



The new conservatory at Trentham — 

 which is a very handsome architectural 

 screen, separating the kitchen garden 

 from the pleasure-ground — is a house 

 very much to our mind, as, while it is 

 capacious, it is not too lofty. The length 

 is 89 feet, and the breadth 60 feet. The 

 roof is a series of spans 9 feet wide, and 

 rising 3 feet to the centre of the span. 

 The sides are 9 feet in height, and are 

 all glazed to the ground, while ventilation 

 is amply provided for. 



In regard to form, we may here 

 observe, that of all other figures, the 

 domical is the worst. And we are not 

 alone in this opinion. The late Mr 

 Loudon, in referring to the destruction 

 of that immense house, the Anthseum, 

 attempted to be erected at Brighton, but 

 which unfortunately fell to pieces long 

 before it could be finished, says of such 

 forms : " When, however, it is seriously 

 contemplated to grow house plants in 

 quantity together, and to a large size, a 

 square or parallelogram will be found the 

 most advantageous ground-plan, with a 

 ridge-and-furrow roof, supported on cast- 

 iron pillars, which might be raised as the 

 plants advance in size. Such a house, 

 whatever might be its extent, would be 

 a mere repetition of two or three very 

 simple parts in straight lines, and would 

 therefore cost very little — at least not 

 one half per superficial foot so much 

 as a dome of such proportions as the 

 Anthseum. 



" A dome is calculated to have a very 

 grand appearance when seen from with- 



out, and also, if comparatively empty, 

 when seen from within ; but when filled 

 with plants, the domical form, and the 

 circumstance of its being without interior 

 supports, pass for nothing. Any one will 

 be convinced of this who has had an op- 

 portunity of examining the exterior and 

 interior of the dome at Sion, or of that 

 once existing at Bretton Hall. Circular 

 houses, composed of a succession of roofs 

 supported by pillars, are totally different 

 constructions, and are scarcely more ex- 

 pensive than the square or parallelograms 

 which we recommend, while their in- 

 terior effect is equal to that of any dome 

 whatever. Let it not be forgotten that 

 the vastness of the hemispherical roof is 

 totally lost in the interior, when the 

 house is entirely or even in part filled 

 with trees." The correctness of this 

 opinion is every day confirmed by the 

 circumstance of this form of roof being 

 entirely discarded. 



One great mistake has been fallen into 

 by most hothouse builders and garden 

 architects, namely, not giving their struc- 

 tures sufficient height of base. We in 

 general see houses otherwise faultless 

 built upon the general ground-level of 

 the garden they are placed in. This cer- 

 tainly should not be the case, for by it the 

 borders are often injured by damp, and 

 the furnace fires drowned out in times of 

 heavy rains, where proper provision for 

 draining them has either not been made, 

 or where it has been impossible to do so ; 

 while, in addition to all this, the houses 

 themselves are deficient in effect for want 

 of elevation. All houses should stand 

 above the ground-level from 2 to 3 feet, 

 according to their size and the length and 

 importance of the range. The borders, if 

 they are fruit-houses, will then have a 

 sufficient slope towards the walk, and the 

 houses be looked up to when viewed from 

 thence. More elegant structures, such as 

 conservatories, should stand high, and be 

 terraced around with all the accompani- 

 ments of parapets, steps, &c; or, for 

 greater effect in the case of forcing-houses, 

 when the range is extensive, the borders 

 may be made level and made good at the 

 front next the walk with a stone ashlar 

 or a brick wall, divided into compart- 

 ments by running up at equal distances 

 pilasters finishing above the wall in 

 square plinths, on which to place vases 



