390 



PLANT-HOUSES. 



very general occurrence—we shall point 

 them out. First, the hot- water pipes are 



placed under the side tables or shelves — 

 of course, the proper position for them ; 

 but then the shelves, which are of stone, 

 are let into the side walls, preventing the 



Fig. 532. 





'£ h -A 





i 9 \ 



9 





heat from ascending and diffusing itself 

 over the inner surface of the glass, losing 

 considerably its effect, and placing the 

 plants on the side tables (in general the 

 most valuable) in danger of being frozen 

 to death during winter. Secondly, when 

 stone shelves are used, (and these, or 

 slate, are the most proper for such pur- 

 poses, so far as durability is concerned,) the 



conduction of cold through the side walls 

 is such as often to freeze the roots of the 

 plants set upon them. Now, both these 

 evils could have been avoided by merely 

 leaving a space of 3 or 4 inches between 

 these shelves and the side walls. From 

 both the sections it will readily be seen 



Fig. 533. 



that, had that precaution been taken, the 

 heat from the pipes would have radiated 

 upwards, and completely cut off the con- 

 nection between the cold air on the 

 surface of the glass and the warmer air 

 of the house within. The system of 

 ventilation shown in fig. 534, more espe- 

 cially during winter, 

 and always in windy 

 weather, would have 

 been improved if 

 ventilators had been 

 placed in the side walls 

 opposite the pipes, as 

 shown in various ex- 

 amples in this work. 

 By this means noctur- 

 nal ventilation could 

 have been indulged in, 

 and air admitted du- 

 ring the day, even in 

 the severest cold or most stormy weather — 

 times when, every sensible cultivator is well 

 aware, the side sashes cannot be opened 

 without great injury to the plants. The 

 rafters are of good size and proportion for 

 the weight they have to carry : we would, 

 however, have preferred them had they ex- 

 hibited less of the moulding-plane. Mould- 

 ings of all kinds should be discarded from 

 houses of this description, as they tend to 

 no good, but much evil — harbouring dust, 

 filth, and damp, and reducing the strength 

 without diminishing the bulk of opaque 

 surface. We do not say, however, that 

 highly-finished conservatories or elegant 

 plant-houses may not be ornamented by 



