Book III. 



PITS, 'stages, doors, paths, &c. 



399 



1676. The fixed rafter-trellis consists ordinarily of three 

 wires, which pass through the points of crosses {fig' 277.), in 

 breadth from fourteen to eighteen inches, and which crosses are 

 screwed to the under edge of the rafter ; the first fixed at the 

 plate of the parapet, and the last at the upper end of the 

 rafter, and the intermediate ones at distances of from three 

 to four feet. 



1677. The moveable rafter-treUis consists of a rod bent parallel 

 to the roof, with horizontal studs or rods, extending from 6 to 

 10 inches on each side, containing two collateral wires, the rod 

 itself forming the third. This rod is hinged, or moves in an 

 eye or loop, fixed either immediately above the plate of the parapet, or near the top of the 

 front glass. It terminates within one or two feet of the back wall, and is suspended 

 from the roof by two or more pieces of chain attached to the studs, the links of which are 

 put on hooks attached to proper parts of the roof. Tlieir advantage is chiefly in the 

 case of very early forcing, when they can be let down two or three feet from the glass, 

 and thus is lessened the risk of injury from frost. A whole sheet or tegument of trellis, 

 if desirable, may be lowered and raised on the same general plan. (See the details, 

 Hort. Trans, vol. iii.) Rafter-trellises are in general used only for such houses as are not 

 chiefly devoted to vines ; such as pineries, peach-houses, and sometimes green-houses. 



1678. The secondary trellis is placed from six inches to eighteen inches behind the 

 first, and is used for training shoots of the current year, while that nearest the light is 

 devoted to such as are charged with fruit. In ordinary trellises, the wires are generally 

 placed from nine inches to a foot asunder, in a horizontal direction ; on the secondary 

 trellis they are placed at double that distance. 



1679. The cross trellis has been sometimes employed in peach-houses, 'and is strongly 

 recommended by Sir George Mackenzie, in what he calls an economical hot-house. These 

 trellises, however, unless kept very low, darken the house to such a degree as to prevent 

 the ripening of fruits. They may be useful for nurserymen for training peaches or fig- 

 trees for sale, but for culinary forcing are worse than useless. Sir G. M.'s house, though 

 lauded by Dr. Duncan {Caled. Memoirs, vol. ii.), was soon obliged to be cleared of its 

 cross trellisses, and restored to the common form. The only houses where such trellises 

 can be used with any reasonable prospect of advantage, are such as are placed south and 

 north, and span-roofed, or glass on all sides. On these two or more lines of low trellis 

 may be placed, and the plants will enjoy the forenoon's sun on one side, and the after- 

 noon's sun on the other. 



1680. The entrance to hot-houses is commonly at each end, and sometimes in the 

 middle, either of which modes answers perfectly where the ground-plan is a parallelo- 

 gram ; but for any description of curvilinear house, the entrance is more commodiously 

 made through a lobby at each end of the house, and which lobby is best formed behind 

 the wall. When there are a number of curvilinear houses placed against one wall, one 

 door in the wall between each will serve every purpose, and the whole will be at once 

 elegant and commodiously connected, {fig- 262.) 



SuBSECT. 9. Paths, Pits, Stages, Shelves, Doors, ^c. 



1681. The j)afAs in hot-houses vary in direction, breadth, and construction. In ge- 

 neral, one path runs parallel to the front, sometimes upon the front flue, but more gene- 

 rally beside it ; at other times, as in peach-houses, it passes near the back wall, or through 

 the middle of the house. In pineries and houses with pits, it generally surrounds 

 these, and in green-houses it is commonly confined to a course parallel to the front 

 and ends. Some of the most ornamental paths we have yet seen have been formed by 

 Messrs. Bailey, oif cast-iron plates, laid over steam-pipes, and so perforated as to form an 

 elegant running pattern, or cast-iron carpet. 



1682. The materials of which the path is composed in the case of some houses, are 

 mere planks, or lattice-work, supported on cross pieces of timber, in order to admit the 

 sun and air to the soil below, and not to indurate it by the pressure of feet. An improve- 

 ment on this mode consists in using grated cast-iron plates, which are more durable, 

 and may be set on iron stakes driven in till their tops are on a level, and at a proper 

 height, &c. These gratings are also particularly preferable when the path is over a flue, 

 not only as presenting a cooler surface to walk on than the covers of the flue, but also by. 

 readily admitting the ascent of the heat in the interstices, and preventing the movement 

 of the covers by the motion of walking. But the best material for a permanent path, as 

 in green-houses, botanic stoves, &c. is argillaceous flag-stone, and of this one of the best 

 varieties is that obtained from Arbroath, and known by the name of Arbroath pavement. 



It is a light grey schistus, which rises in lamina of from three to six inches in thick- / 

 ness, and eight or ten feet square ; requires very little work on the surface ; and has the 

 property of but very slightly absorbing moisture from the atmosphere, or from the 



