lt.70. ] 
GLASS WALLS FOE IIOUTICULTUEAL rUllFOSES. 
189 
water, and sewage pipes, and its goodly figure every where being marred into 
liideousness by Imge masses of bricks and mortar, that crushed down the 
oppressed eartii by their weight, and shut out the cheering sun by their shadows. 
There was onl}^ too much truth in the picture. It seems as if the great globe 
itself” was in danger of being converted into dwelling-houses and workshops for 
man. The space occupied by buildings is immense. Walls are thick as well as 
high. For dwelling-houses, &;c., this thickness is necessary, and cannot well be 
lessened ; but for many other 
purposes for which walls are 
used, such as for training 
trees upon, or for forming 
•screens or dividing-lines be¬ 
tween gardens and other pro- 
23erties, the thickness of the 
wall represents so much waste 
of space. The saving of 
ground will be immense, if 
for every 14-in, or 9-in. wall we use for such purpose, a 1-in. wall can be sub¬ 
stituted, while we shall get better walls for horticultural purposes into the bar¬ 
gain ; for they will not only stand upon about one inch of ground, but they will 
not injuriously shade or diminish space behind them. The light and the heat 
will pass through, and the trees on each side, and both sides of the trees, will 
live in the light, and enjoy the heat of the sun. 
While this transparency will prove a clear cultural gain of immense advan¬ 
tage, and promote the breadth, 
and develope to the utmost the 
strength, beaut}^, and fruitful¬ 
ness of plants trained on such 
walls, it will likewise enable 
them to be packed closely to¬ 
gether for the purpose of train¬ 
ing or fruit - growing. The 
shadow of opaque walls has 
necessitated a considerable in¬ 
terval between them. To derive 
the full advantage from walls 
O 
us ameliorators of climate, they should be separated by spaces as wide again as 
their heights. But these walls may be massed together in block, and thus pro¬ 
vide the widest possible area of wall surface on a small space. This grouping 
together of Avails has other advantages besides the economizing of space. It 
must facilitate their protection from frosts and birds by horizontal coverings, and 
the radiating of heat from a series of walls near to each other must improve the 
