VINERIES. 



319 



or straight portion of the roof, are 

 attached, (the roof being all in one piece, 

 not divided by rafters and sashes,) as 

 well as to the ridge-board, as in ordinary 

 span-roofed houses. Here we think some 

 important objects are gained — namely, 

 the curved metallic part is so low down 

 that the conduction of heat by it can 

 do little or no injury to the plants within ; 

 the expense of front lights and top wall- 

 plate is dispensed with ; the upper part, 

 on which the sun has most effect, being 

 of wood, we have all the advantages given 

 to curvilinear roofs, without the bad 

 effects attending them when of iron. 

 The ends may be all of metallic astragals 

 and framework, which will give to the 

 structure a lighter appearance ; and as 

 the house is intended to run from north 

 to south, the conducting powers of the 

 iron there will scarcely be perceptible. 

 Ventilation is to be effected as in the last 

 example. 



The majority of vineries built of late 

 years have been made too narrow. These 

 are undoubtedly adapted for early forcing ; 

 but for general crops, houses of much 

 greater breadth will be found superior. 

 We may here remark that, as regards 

 the size of vineries, singular changes have 

 taken place. The earliest erections in 

 this country, copied from the Dutch, were 

 narrow ; then came houses of much 

 greater breadth, as may still be seen in 

 the few examples left of those built about 

 the latter end of the last century. The 

 beginning of the present century brought 

 into vogue narrow vineries again, no 

 doubt arising in a great degree from 

 the examples furnished by Mr Atkinson. 

 Of late, broader houses have been recom- 

 mended ; and for general crops in large 

 establishments, this principle is undoubt- 

 edly correct. In this particular, the 

 vineries at Frogmore afford excellent 

 examples. 



The annexed example, fig. 434, is what 

 we would call a very excellent house for 

 this purpose : it has some peculiarities 

 about it differing from the structures in 

 ordinary use. The houses are each 

 50 feet in length, and 20 in breadth : 

 they may either be on the ridge-and- 

 furrow principle, or constructed with two 

 top sashes in the ordinary way, and as 

 shown in section. The front wall should 

 be of brick or stone ashlar, with venti- 



lators 3 feet long and 9 inches broad 

 in the opening, distributed equally along 



Fig. 434. 



0 5 ll, 



the front. This wall is to be 3 feet high, 

 and built upon stone or brick pillars, 

 arched or lintelled over with pavement, 

 stone, or bars of cast-iron, to permit the 

 roots of the vines to pass out to the 

 external border. 



The back wall is to be 14 feet high 

 from the ground line to top of coping, 

 and 12 feet high from border level to 

 inside of glass roof. Ventilators, b, of the 

 same size as in front, are to be placed 

 along the top of the back wall, which 

 should reach within 6 inches of the 

 glass. 



Ample though this extent of ventila- 

 tion may appear, still we would provide 

 means for increasing it, and therefore 

 would bring air-drains, by means of 

 tubular tiles 10 inches in diameter, c, 

 from the front, through under the parapet 

 wall, as shown in section, and lead them 

 under the hot-water pipes, having their 

 opening, d, close to the floor, and 8 feet 

 within the house. Similar tubular drains 

 should be brought through under the 

 back wall, having their openings at e, 

 close to the trellised footpaths : these 

 tubular ventilators to be placed under 

 the front ventilators, and in the same 

 proportion to numbers. This under- 

 ground ventilation should be regulated 

 from within the house by proper covers 

 or stoppers being fitted to the mouths 

 of the tiles ; and for this purpose nothing, 

 perhaps, would look neater, or answer 

 the end better, than brass revolving venti- 

 lators j or the whole may be opened and 

 shut by machinery of a very simple form. 

 The vines are to be trained all over the 

 roof and also against the back wall. As 

 vineries of this size are too large for 

 early forcing, the roof may be fixed, 



