258 
GARDEN ARCHITECTURE. 
of the greatest ornaments imaginable to the pleasure-grounds ; and by their parti- 
tion into compartments of any required length, each heated from the centre, and 
having a system of hot- water pipes independent of all the rest, and capable of being 
warmed or not at pleasure, the various tribes of plants might be arranged into 
groups in accordance with their appetencies, and every one of these might be 
allowed an aspect and a temperature such as it naturally delights in. Space 
precludes us from saying more on this occasion than that we have always enter- 
tained the belief that the only way to cultivate tender exotics to perfection is to 
separate them into classes as above hinted ; and we know of no system by which 
this could be so well accomplished as that of erecting a circular range of houses for 
their reception. 
For ventilating plant-houses different plans must be pursued in regard to the 
mode of their construction. A span-roofed house should have its side-lights hinged 
at the top, or fixed on pivots on each side of the middle, with a flat perforated 
piece of iron attached to the bottom, the perforations made at intervals of an inch 
to fit on a small iron rod in the lower part of the frame, in order to fasten the 
sashes open, and secure them when they are closed. By opening all or a portion 
of these on one or both sides of the house, according to the season, the state of the 
atmosphere, and the power of the wind, at the same time, in greenhouses, having a 
few of the upper lights capable of sliding, a kind and degree of ventilation may be 
obtained, which is exactly what could be desired for the inhabitants of the green- 
house. Of course, a less command of air will be necessary for the stove, though 
the same amount should be provided, with the exception of the movability of 
the superior lights, (which can be fixtures,) to be made use of at the discretion of 
the manager. In an orchidaceous-house, side-lights will be superfluous, and the 
ventilation may be effected by means of iron or wooden slides in the walls, beneath 
the outer stages. 
Structures with curved and fixed roofs are differently ventilated. In these, the 
air should enter, through the medium of iron or wooden shutters, regulated as to 
size and number by the nature of the plants to be grown, and placed below the 
side stages. Similar shutters should be provided, at somewhat corresponding 
intervals, along the summit of the roof ; it being of little moment whether this 
narrow surface is glazed or opaque, because the sun never shines in precisely a 
vertical manner, and if he did, this would be at a period when a slight obstruction 
to his rays would be rather useful. We may note, that the best principles of ventila- 
tion are involved in the process just sketched. Cool and heavy air entering at the 
base of a building, naturally drives the warmer and lighter air to the top of the 
roof; and as arrangements are here made for its escape, the most rapid and 
thorough circulation is effected. In the new conservatory erected at the gardens of 
the Horticultural Society, a cistern of water passes all round the inside of the house, 
immediately under the ventilators, thus both cooling the entering current, and 
charging it with moisture. 
