30 FRUIT AND KITCHEN GARDEN. 
and embryo fruit from the hoarfrost, and when danger ia 
past are removed to give free access to the genial showers 
and sunshine of summer and autumn. 
Hot Walls.—A considerable proportion of the wails of 
every good garden, especially in the north, should be con- 
structed with flues to supply the means of applying arti- 
ficial heat. The additional expense is trifling; and, in 
cold seasons and cold situations, the aid of this species of 
wall is nearly indispensable for the regular ripening of 
grapes, apricots, and figs, as exemplified at Erskine House 
on the Clyde, where, with the assistance of a little fire- 
heat, large and high-flavored black Hamburgh grapes are 
produced, and where Mayduke cherries have been ripened 
at least six weeks before the usual period. The application 
of fire-heat for a few weeks in spring will secure the setting 
of the fruit, and the same operation continued for a short 
time in autumn will suffice to ripen it, and also to prepare 
the young wood for the next year. The flues may be about 
twenty inches deep, and should make as many horizontal 
turns as the height of the wall will permit. One furnace 
will be enough for a surface fifty feet in length. When 
the boundary walls do not furnish room sufficient for the 
production of the finer fruits, cross walls are built athwart 
the garden from east to west, of the same height ag the ‘side 
walls, to which they nearly approach. They are generally 
flued, and are sometimes furnished, on their southern 
aspect, with sloping glazed frames, either fixed or movable. 
These cross walls add greatly to the capabilities of a fruit- 
garden, and are useful in affording additional shelter to the 
small fruits and crops of vegetables in the culinary quarters. 
Espalier-Ratls.—Subsidiary to walls as a means of train- 
ing fruit-trees, espalier-rails were formerly much employed, 
and they still prevail in many parts of England. In theit 
