119 
for the roots of a wall tree in the border in front, without invit- 
ing them into the border behind. Arched walls are only ne- 
cessary for the front walls of vineries or peach-houses. For the 
safety of the walls, they should be built with piers or pilasters 
behind, twenty or thirty feet apart, and projecting four inches 
from the face of the wall. Low walls are much more conveni- 
ent in the management of the trees, than those requiring ladders 
to perform the necessary business ; and all fruit trees extended 
horizontally are for the most part much more fertile, and cer- 
tainly easier defended and under more control than if trained 
upright, and high up out of reach : so that two walls of six 
feet in height, with trees planted at good distances from each 
other, will yield during any term of years, much more fruit 
than one wall of twelve feet in height. True it is, we often see 
pears or vines trained to a great height on buildings; but the 
value of the fruit is (supposing the trees are fruitful) much les- 
sened, when the great trouble and danger of dressing the trees 
is taken into account. Besides high walls are by no means ne- 
cessary for the crops of either a fruit or kitchen garden. A free 
ventilation is necessary at all times The effects of high winds 
are much less to be dreaded than those of foul, stagnated air, 
pent up all round by lofty walls. 
The advantages of walls for the protection and ripening of 
exotic fruit, need not be insisted on. Their reflection of the 
sun’s light, and retention of his heat throughout the greater 
j)ortion of the night, are the favouring circumstances which 
forward as well as <lefend the tender trees; and at the same 
time, the branches being all securely fastened, and trained in 
any form to the wall, renders them safe from the violence of 
storm or tempest. Walls ol' a moderate height, however, are 
preferable to over-lofty ones, more especially if the upper part 
of them be naked. )\Iany of our best fruits are naturally dwarf- 
ish, and we take pains to make them more so. How ridiculous 
then it is, to see such dwarfed trees planted against a wall of treble 
their full-grown height. For the convenient culture of dwarf 
fruit trees, low walls are sometimes built across gardens of suffi- 
cient extent. These are usually nine-inch work, with pilasters 
of fourteen-inch work, at about sixteen feet distances behind. 
The height need not be more than six feet, and on which great 
quantities of fruit may be produced both in front and on the back ; 
160 ACCT^KICM. 
