BOOK III. 



PORTABLE STRUCTURES. 



299 



on three sides by boards or canvass, and on the fourth side by glass doors. This stage, 

 when in use, is placed so as the glazed side may front the morning sun, or the north, 

 so as the colors of auriculas, carnations, &c. may not be 

 impaired by him. (See FLORICULTURE, Part III. Book II. 

 Ch. VIII.) 



1 528. The decorative stage consists of shelves rising in gra- 

 dation, in various forms, according to taste, and particular 

 situation. Those to be viewed on all sides are commonly co- 

 nical (fig. 222.) or pyramidal ; those to be seen only on one 

 side triangular. They are constructed either of boards or 

 iron work, and placed in parterres, open courts, and large 

 chambers. 



1529. The opaque covering-frames are borders of board, strengthened by cross or diagonal 

 slips of wood or rods of iron, and covered with canvass, gauze, woollen, or common net- 

 ting, or soiled paper. They are used for protecting plants from cold, or for sheltering 

 from wind, or shading, either singly, supported by props, or connected so as to form roofs, 

 cases, or enclosures. 



1530. The transparent covering, or glazed frame or sash, consists of a boundary frame com- 

 posed of two side pieces called styles, and two end pieces called the top and bottom rails, 

 with the interspace divided by rabbeted bars to contain the glass. It is used as the 

 opaque covering frames, and has the advantage of them in admitting abundance of light. 

 In general the rabbeted bars are inserted in one plane, as in common hot-bed sashes ; 

 but in some cases the surface is in angular ridges, or ridge and furrow-work (fig. 223.), 

 cuneform (Jig. 224.), or trigonal (Jig. 225.), in order, in each of these cases, to admit 



223 



224 



225 



more of the rays of the sun in the morning and afternoon, and to moderate it in the middle 

 hours of the day. Such frames are used for placing over beds of hot dung, for growing 

 cucumbers, forcing roots or flowers, and for a great variety of purposes. The materials of 

 sashes is commonly timber, but iron, cast and wrought, and copper, are also used. 



1531. The common glass case is a glazed wooden frame or frames, so contrived as to fit 

 together, and cover either single trees, espaliers, or shrubs too large for the hand-glass. 

 The flavor of plums and cherries on espa- 226 



liers in bad seasons is much improved by the 

 use of this structure. In France it is chiefly 

 used for peaches. For orange-trees, it con- 

 sists of a number of frames, chiefly parallelo- 

 grams, but partly right-angled triangles 

 (Jig. 226-), easily put together and taken 

 asunder, to be used in the summer months in 

 growing melons, or covering walls or espalier 

 rails ; and in winter in protecting orange-trees 

 in situations where they are planted in rows against walls, or in groves in the open air. 



1532. The hot-bed frame is of three species, the common, fixed-bottomed, and move- 

 able-bottomed. 



1533. The common hot-bed frame is a rectangular box of wood, bottomless and highest 

 at the side to be placed to the north, subdivided by cross bars dove-tailed into the outer 

 frame, and each subdivision covered by a glazed sash. Knight, instead of having the 

 north side of the frame highest, has all the four sides of equal height, but forms the base 

 ment of the dung-bed, and builds the dung-bed itself of that slope which he thinks most 

 suitable for the sashes of hot-beds. 



1534. The fixed-bottomed frame is the common hot-bed frame, with a boarded bottom 

 for the retention of earth. In the boards are holes for the emission of water. 



1535. The adjusting-bottomed frame has a box for the earth, of the size of the inside di- 

 mensions of the frame, and the frame being deep or placed on walls, like those of a pit, 

 the bottom and its earth and plants, or its pots and plants, may be raised or lowered by a 



