8o THE ART AND PRACTICE OF LANDSCAPE GARDENING. 



basin ; or it can have a border next it, and be wired for the growth 

 of climbing plants ; or it can be recessed and lined with tufa, 

 with pockets of soil for ferns, etc. ; or space may be arranged for 

 a fountain basin, or for water dripping from the rockwork into a 

 pool. It is well to avoid as much as possible the employment of 

 iron in continuous lengths, and the rafters should be moulded with 

 drips to take away any superfluous moisture. The heating apparatus 

 can be placed under part of the conservatory, or in an adjacent 

 building, or, if near, the heating can be connected with that of the 

 growing-houses. The general details of construction and heating 

 given for hothouses later on, apply also to conservatory work. 



Growing-houses are built for utility rather than for show ; and 

 therefore it is desirable to construct them with the view of obtaining 

 best results for the well-doing of the plants. A great deal might 

 be written about the best pitch for the roof, or the angle which is 

 made between the roof and a horizontal line drawn from the lowest 

 point of it. The sun's rays naturally strike the glass with greatest 

 intensity when it is placed at right angles to them ; but if the sun's 

 rays strike the glass at any angle between 60 and 90, only about 

 2'/ 2 per cent, is lost, so we have practically a range of 30 on each side 

 of the perpendicular. The angle at which the sun's rays strike a sur- 

 face in the same latitude varies considerably in summer and winter. 

 In summer the angle of the sun's maximum altitude here is 62, and 

 in the winter it is 15. In addition, it is well to remember that 

 the difference in the length of a sunlight day in midsummer and in 

 midwinter is 17 hours as against 7 hours. The higher the latitude, the 

 greater should be the pitch of roof; thus for latitude 50, the pitch 

 would be 36, and for latitude 60, 46. In growing-houses, however, 

 sunlight is not the all-important question. It is desirable that 

 plants should be as near the glass as possible. A pitch that is 

 constructionally good, viz., 26 or 6" in the foot is a very good 



