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CHAP TEE III. 



HOTHOUSE-BUILDING. 



§ 1. — GENERAL PRINCIPLES. 



Impeovements in hothouse-building ap- 

 pear to bear no comparison with the 

 improvements that have taken place of 

 late years in other departments of horti- 

 culture. This seems sufficiently proved 

 by the fact, that so few — not more than 

 half-a-dozen cases— of even very modified 

 improvements have been exhibited in the 

 Crystal Palace. Of these we notice two 

 model greenhouses by Mr Dench, in 

 which the metallic sashes are galvanised, 

 and corrugated galvanised iron plates are 

 employed to form the outside of the front 

 parapet wall, while plain plates are used 

 inside, as substitutes for a brick wall. 

 Some parts of the woodwork are left 

 plain, while others are covered with thin 

 plates of iron. If we are to have metallic 

 hothouses, let us have them out and out; 

 but all combinations of wood and iron, 

 such as those here presented, are behind 

 the intelligeDce of the age. The other 

 improvements exhibited in the Crystal 

 Palace appeared to us to possess neither 

 novelty nor merit. What Mr Dench's 

 motive may be for substituting plates of 

 iron for brick in the parapet walls we know 

 not. This much is certain, that they are 

 neither so cheap nor so capable of resisting 

 cold. 



Viewing the Exhibition, therefore, in a 

 horticultural point of view, we are com- 

 pelled to confess our great disappointment 

 at its presenting so few specimens of im- 

 provements in this department. We had, 

 indeed, glass of all shapes and sizes; but 

 we looked in vain for specimens of glaz- 

 ing, although a matter of so much im- 

 portance. Even the almost worn-out 

 subject of heating seemed to have been lost 



sight of, if we except a few of those health- 

 destroying toys called " hot-air stoves." 

 From the painting of the interior, so 

 artistically carried out by Mr Owen Jones, 

 the ornamental hothouse-builder may take 

 useful hints; and future conservatories at 

 least may bear some evidence of the im- 

 proved taste of 1851. 



We need not refer to the original con- 

 struction of hothouses, either in this 

 country or on the Continent, further than 

 to remark that they were by no means 

 calculated for the preservation of tender 

 exotic plants, and still less for the produc- 

 tion of tropical fruits — as they were little 

 other than large rooms, having windows 

 in front, more in number and of larger 

 size than those used in dwelling-houses. 

 The first improvement on these was the 

 adoption of what has been called the 

 lean-to roof; this, till about the begin- 

 ning of the present century, continued to 

 be the form in general use, and for some 

 purposes it will probably continue to be 

 so. Various improvements, more espe- 

 cially as regards their internal arrange- 

 ments, mode of heating, &c, were pro- 

 jected, and carried into beneficial effect 

 by the garden architects of the day ; 

 amongst whom the late Thos. And. 

 Knight held a conspicuous position, and 

 revived the views laid down by Boer- 

 haave about a century previously, as to 

 arranging the angle of the roof to the 

 situation and purpose for which the house 

 was principally intended. — ( Vide sec. 

 Angle of Elevation.) 



Sir George M'Kenzie, a few years after- 

 wards (1815,) proposed what he thought 

 to be the best form of roof for the 

 admission of the greatest possible quan- 

 tity of the sun's rays — namely, a hemi- 



