1,58 



IMPROVEMENTS IN THE CULTURE OF 



is placed at one end ; the flue proceeds from it di- 

 rectly to the front parapet ( b ), and passing along 

 close under it to the opposite end, there terminates 

 in a chimney ( c ). Instead of a pit, a curious 

 stage is constructed, by forming cross walls ( d ), 

 or rather piers, connected by arches, and finished 

 by a gradation of flat surfaces, or steps, on which 

 the pots are placed, so as to stand as near the glass 

 as possible (fig. 20.) 



Air is admitted by shutters, which open out- 

 wards, immediately under the stone plinth of the 

 parapet (fig. 20. a), in which the lower ends of the 

 iron bars are fixed ; and allowed to escape by simi- 

 lar shutters, opening outwards, immediately under 

 the stone coping of the back wall (b), in which the 

 upper ends of the same bars are leaded in. The 

 path behind is on a level with the exterior surface ; 

 the width of the cross walls the length of a brick, 

 or nine inches, and they are finished with foot 

 tyles; the width between them is about fifteen 

 inches, by which means, any ordinary sized person 

 may pass from the back path to the front flue, and 

 water or examine the plants on each side. 



19 



