20 
ERECTION AND MANAGEMENT OF GREENHOUSES. 
Our new greenhouse at Chatsworth is so constructed, that scarcely 
any more light is obstructed than in a metal roofed*house, but it 
possesses at the same time all the advantages of wood. 
Its whole length is ninety-seven and a half feet, and its breadth 
from the hack wall ( a ) to the front lights [b) twenty-six feet.* The 
roof is supported by two rows of cast iron pillars, one row along the 
centre of the house (c), and another along the front and end as {cl). 
These pillars are placed six feet and a half apart in the rows, and are 
each three inches diameter; the front ones are made hollow so as to 
admit a leaden pipe, which carries off the water from the roof, into a 
drain laid in the gravel walk, on the outside of the house; this en¬ 
tirely does away with the appearance of a spout. At the bottom of 
the iron pillars there are sockets ( e ) which let into the stone, and 
thus give the pillars firmness, and through this socket the pipe des¬ 
cends into the drain* 
4 
The -elevation at the back wall is thirteen feet six inches, at the 
lowest part, and fifteen feet at the highest part or ridge of the angle; 
the height in front is eight feet six inches in the valley, and ten feet 
to the ridge of the angle. The lights of the roof ( g) are made fast, 
and fixed on the angle fashion, each light is twenty-five feet, six 
inches long. All the front and end lights slide in a double groove 
[h), so that although there is no door, yet a person may enter in at 
any part of the house. 
The centre row of pillars (c) are two feet six inches longer than 
the front or end pillars; about two feet from the bottom of each, a 
small hole (i) is left, through which a screw passes, to fasten the 
bearer which supports the centre, walk (j), on the top of these pillars 
is also fixed another iron support {k) which is formed to rise up to 
the ridge of each angle; each of these arched supports, have at their 
ends a small square part (l) which fixes into a hollow left at the top 
of each pillar {m), and after being properly adjusted they are fas¬ 
tened by running a little matted lead into the interstices. 
In each valley of the angles two large screws are inserted into the 
styles of the lights, to fasten them firm. Air is admitted by sliding 
the front sashes, and by ventilators in the back wall (o), which are 
made to swing on pivots, and open by means of long iron rods, hav¬ 
ing holes to fix on pins driven in the wall, so as to regulate the pro¬ 
portion of air at pleasure ( p .) To prevent these ventilators from being 
unsightly, a square piece of trellis work is placed over the opening- 
inside of the house, as may be seen in the perspective view. 
The house is heated by four fires; the flue covers are dished for 
* Sec Copper Plate Engraving. 
