PLANTS, WITH GLASS ROOFS. 185 



water, watering-pots with the grating described by Mr. Beaton (p. 104) 

 should be used. 



The different kinds of fixed structures for plants, are the pit, the 

 greenhouse, the orangery, the conservatory, the plant stove, the pine 

 stove, the forcing-house, the orchid-house, and the orchard-house. 

 We shall conclude by shortly noticing the characteristic features of 

 these, and their varieties. 



Pits are low buildings with glass roofs, but without glass in the 

 sides or ends. The angle of the roof is between 15 and 25 with the 

 horizon, and the surrounding walls are generally built of brick, and 

 hollow, or in some kinds of pits they are pigeon-holed, or with thin 

 panels to admit the heat of exterior casings. The provision for 

 heating varies from the mere power of retaining natural heat by 

 coverings of glass or other materials, to the obtaining of 70 or 80 or 

 upwards of artificial heat, which may be supplied either by fermenting 

 materials or fire-heat, or by both combined. The cold-pit is without 

 any artificial source of heating, and in some its walls are of turf or 

 earth ; and instead of glass sashes, frames of reeds, or boards, or 

 thatched hurdles, or other coverings, are substituted. The cold pit 

 is used for protecting plants in pots not in a growing state, or for 

 preserving culinary vegetables from the frost. In warm situations 

 and dry soil, it has a thick mound of earth, or thick wall of turf, which 

 in either case should be coped so as to be kept as dry as possible. Even 

 in the case of brick pits, an outer casing of dry turf prevents to a very 

 great extent the effects of frost and sudden changes of temperature. 

 The casing may also be made of boards, where great neatness is an 

 object, leaving a cavity to be filled with coal-ashes, charcoal, dry sand, 

 or other non-conducting materials. In pits of this kind, with glass 

 sashes instead of opaque covers, many hard-wooded greenhouse plants, 

 such as camellias, rnyrtaceae, heaths, &c., may be preserved through the 

 winter without any artificial heat, care being taken to adapt the nightly 

 coverings to the weather. The usual width of such pits is from six to 

 eight feet ; height of the back wall, three to five feet ; and of the front 

 wall, two to three feet. A pit to be heated by a bed of tan within, and 

 exterior cases of dung, may be of the same or larger dimensions, 

 with the back and front wall pigeon-holed or panelled (p. 164), and with 

 boarded covers to protect the linings from rain and wind, hinged to 

 the wall-plate. Instead of exterior linings for supplying extra heat, 

 flues or hot-water pipes may be introduced along the front and ends, 

 or entirely round the pit ; sometimes with a platform of boards over 

 them for plants in pots, or even for a bed of soil, but more frequently 

 separated from the bed of tan by a narrow wall, or by a partition of 

 slates or flacr-stones. The width of the bark-bed in such pits is seldom 

 less than five or six feet, and eighteen inches of additional width is 

 necessary for the front flue, or four-inch pipes 5 and double these 

 widths if the flues or pipes are carried round the house. For the 

 more convenient management of pits, they are sometimes constructed 

 sufficiently high behind to admit of walking upright there ; and a 

 passage for that purppse is left at the back, of three or four feet in 



