74 
OBSERVATIONS ON THE ROOFING OF HOT-IIOUSES. 
glazed lights or sashes, which are fixed ; and these falling east and 
west from the higher to the lower rafters or principals. Thus the 
•whole length of roof will be formed into ridges and valleys; and the 
front eaves will present a series of little glazed gables, This form of 
roof renders gutters necessary in every valley, and pipes at the bottom 
of each, to carry off the rain, and melted snow water from the roof. 
By this disposition of the glass lights, it is obvious that the greater 
part of every ray of light from the eastward will be admitted, and 
also the same from the west. And, moreover, the heat of the meridian 
sun will be so far qualified by the shadows of the bearers, the short 
rafters, and frames of the lights, together with the refracted transmission 
of the rays through the obliquely lying glass, that no extreme degree 
of heat need be feared in the middle of the day, nor yet will there be 
any prejudicial want of light at any time. 
We know not how such a house is ventilated, but, besides the 
facilities afforded by the upright front and ends, many simple con¬ 
trivances may be thought of to allow the escape of over-heated air. 
In the further consideration of this new method of roofing hot¬ 
houses, we have, in the first place, to notice how far it may, or may not, 
be suited to the changes of weather experienced in this climate. On 
a first view, its liability to collect and retain an inconvenient load of 
snow, seems to be the most material objection ; because, although a 
coat of snow is soon melted off a forcing house, yet, as it would keep slip¬ 
ping down into the gutters, attention will be required to keep them free. 
In the second place, how will such an irregular roof suit the plants 
cultivated under it ? The irregularity of a roof can make no difference 
to plants not trained to it, such as pines and collections of stove or 
greenhouse plants ; but for a vinery it does not at all appear to be con¬ 
venient, because though a wire-trellis could be made parallel to the 
surface of glass, still, from its wavy position, it would be, we think, at 
least inconvenient to the vine-dresser. The same objection may be 
made to training peach-trees on such a roof; but we are not aware of 
any other defect or inconvenience to which the plan is liable. 
It may be thought, perhaps, that all the advantages alluded to 
might be gained by placing the forcing-house north and south, instead 
of east and west, and covering it with a common roof, falling both 
ways, and to build at the north end a high sheltering wall. This 
would receive all the benefit of fore and afternoon light; and would 
also be as shady in the middle of the day, as the other more complicated 
roof. But, as we are yet imperfectly acquainted with all the merits of 
the Paxton roof, we shall add nothing further concerning it, till we 
re-examine the promised drawings. 
(To he continued .) 
