AGRICULTURE. 145 
shelves for the sheaves of grain which are replenished from the stacks with- 
out continually, as the grain is threshed 
D. Root and Fruit Crops. 
Root crops, such as potatoes, turnips, and the like, are preserved in cel- 
lars or in holes in the ground, or even, where the cold is not too severe, in 
heaps raised above the surface and covered with earth. Pl. 30, figs. 
31a and 31c, represent such an arrangement. The roots are heaped and 
covered first with straw, then earth to a depth sufficient to exclude the frost ; 
in the centre of the heap is a hole usually filled with straw, in which a ther- 
mometer (jig. 24) is placed. This thermometer is occasionally examined, 
that frost and fermentation may be guarded against; sometimes the roots 
are heaped upon the surface covered with light frames (fig. 316), and then 
with straw, the ends being filled with straw that access may be had to the 
roots. Clover hay requires peculiar management, otherwise the leaves fall 
from the stalks and its value is diminished. It should be mowed when a 
majority of the flower-heads are developed, and left one day in the swath. 
The next day the swaths are to be turned so that two fall together ; it is then 
left until nearly dry, and when the stems on being beaten cease to show any 
moisture, it is gathered in when the dew is upon it. Upon the continent of 
Europe it is sometimes cured upon frames made for the purpose, called 
clover-horses (pl. 30, jig. 27). ig. 28 is also a form of frame used for the 
same purpose, the object in both cases being to secure a free ventilation 
amongst the clover, which is arranged with the flower heads inside, that they 
may not suffer so much from the rain. 
The drying of frwit can only be performed in dry weather, when this is 
done in the open air. When it is carried on upon a large scale, kilns built 
for the purpose become necessary. In pl. 30, jig. 35, is a plan of such a 
kiln, on the line, ex, of jig. 36; jig. 86, a vertical section upon the line, 
rs, of fig. 38; fig. 37, a transverse section on the line, ex, in fig. 88; jig. 38, 
a horizontal section on the line, ex, in jig. 36; and jig. 39 is a perspective 
view of one of the sliding frames for holding the fruit. Beneath the drying 
chamber is an oven, and at m are openings for the entrance of air which 
passes through tubes, «, to the fruit-chamber, and is again drawn off by the 
tube, x, and carried beneath the fire-grate to save fuel, and to increase the 
draught in the drying-chamber. 
E. Under-Ground Drains. 
When from the nature of the subsoil an excess of moisture exists in the 
soil, excluding the atmosphere, the evil must be corrected by under-ground 
drainage. Soils of this moist, cold nature, are unsuited to the growth of 
any cultivated plants, though particularly congenial to that of weeds. Sur- 
face draining does not accomplish the desired end; indeed this can only be 
effected by deep under-ground drains, which, lying beneath the surface, 
collect the water from a considerable distance, whilst the cultivation of the 
ground is not interrupted. 
The first thing to be attended to in laying out drains is to give them a 
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