388 



PLANT-HOUSES. 



the top, the panes may be 2 feet in 

 length. Towards the front, where the 

 curvature is much greater, the glass 

 should be cut much shorter, so that it 

 may fit properly into the rebate ; or it 

 may be bent in making, to suit the exact 

 curve — which, of course, would have a 

 more elegant appearance, and not add 

 much to the cost. The two end astragals 

 will require to be made four times the 

 thickness of the others, as the upright 

 ones in the gables have to be fastened to 



them : their outer edges also should be 

 plain. The front and end windows should 

 all be made to open; and the best way 

 of hanging them is upon a pivot at top 

 and bottom — or, better, to run on rails 

 fixed to the plinth, and made to pass 

 behind or in front of each other. By 

 this latter plan they are in less danger 

 of being broken by the wind while open. 



As an example of a greenhouse to stand 

 clear of all other buildings, we may offer 

 the annexed fig., 527, which shows an 



Fig. 527. 



elliptical structure, set on a parapet of 

 polished ashlar stone, with ventilators 

 all round. The whole roof is a fixture, 

 and of metallic material. The elliptical 

 part of the roof at top is hid by an orna- 

 mental entablature or parapet of thin 

 and open cast-iron, within which is an 

 inner roof of glass rising from the girder 

 which supports the entablature (and 

 which itself also forms a water gutter) to 

 the top of the base on which the urn4ike 

 chimney-top is placed, and so constructed 

 that half of its whole area opens for 

 ventilation, and is acted upon by a simple 

 mechanical process. The entablature is 

 supported by four cast-iron ornamental 

 columns b, &c, as shown on the ground- 

 plan, fig. 528 j while the smoke is made 

 to pass up the circular metallic column, c, 

 in the centre, the furnace being placed 

 in a vault beneath the floor, and the 



hot-water pipes running round the sides 

 of the house, rising above the floor level 

 at a, branching to the right hand and to 

 the left, and returning when they approach 

 the door entrance. 



Fig. 528. 



In the ground-plan, a is the point at 

 which the hot-water pipes enter the 



