476 THE VILLA GARDENER. 



suitable. In the case of plant cabinets facing the north, where the expense 

 of the double-glazed roof and sides is considei-ed too great, arrangements 

 should be made for forming a temporary inner roof of matting or canvass, 

 for the purpose of retaining the heat during the night, and even some- 

 times during the day in severe weather. An inner covering of matting or 

 canvass, at 6 or 8 inches distance from the glass, is always much more 

 powerful in retaining heat, than if the same covering had been placed out- 

 side the glass ; because in the inside it is kept dry, whereas on the out- 

 side it will be liable to become saturated witli wet ; and in that state it 

 would carry off much more heat by evaporation, than can possibly take 

 place from water running down the smooth surface of the glass. There is 

 another reason against all outside coverings except those of boards, which is, 

 that they are apt to be deranged, and to break the glass during high winds. 

 The inside covering may be made to roll up like a window-blind, and it 

 may rest on iron rods, placed parallel to the roof and to the sides, and 

 about 8 in. distant from them. In many cases, shutters may be contrived for 

 the roof, and put on from an upper window ; and this covering, when the 

 weather is extremely severe, may be left on for two or three days at a time ; 

 it being understood that light is freely admitted from the sides. Provided 

 that the roof of a greenhouse is securely protected from perpendicular cold, 

 as it is called, a covering for the sides is comparatively of little importance. 

 We may add that, among nurserymen and commercial gardeners, a substitute 

 for these different coverings is found in tying or nailing bast mats to the 

 trellis or rafters of the roof and sides, inside the house ; and, as such cover- 

 ings are seldom wanted above a month or two in the year, during the depth 

 of winter, it is hardly worth while going to the expense of having them made 

 of canvass for the inside, or of boards for the outside. 



522. The placing of the plants in the interior of a plant cabinet should vary 

 according to the size of the cabinet and its situation. Where the cabinet is 

 10 ft. or 12 ft. wide, and of an equal or greater length, a narrow stage in the 

 middle, with a shelf a foot broad round the sides, will display the plants to 

 the greatest advantage ; but this supposes that there is nothing disagreeable 

 in the exterior scenery, which will be seen through the side windows. Where 

 it is not desirable that the external objects should be seen, the stage, instead 

 of being in the middle, should be ranged along the sides and the farther end, 

 and in that case no more of the sides require to be glazed than what is above 

 the highest shelf of the stage. As the main object is to display the plants 

 to the spectator within, and as, Avhen placed in close ranks on a stage, such 

 plants can only be seen on one side, the admission of light to their other side, 

 as it would chiefly strike the under sides of the leaves, is comparatively of 

 little use ; and hence, that portion of the side and end walls which is under 

 the level of the top shelf of the side and end stages may always be con- 

 structed of opaque materials, such as brick, lath and plaster, &c., which will 

 be a considerable saving in first cost. In general, wherever there are objects 

 exterior to the plant cabinet which it is not desirable to see, the stage should 

 be placed against the side walls and the further end ; but, where there is 

 abundance of light on eveiy side, and nothing without to conceal, the best 

 effect to the eye will be produced by bringing the glass down to the ground on 

 every side and the farther end, and by having the stage in the centre. 



523. The mode of heating a j)l(int cabinet is sometimes a matter of difficulty, 



