AGRICULTURAL METEOROLOGY. Lay 
many purposes the cloth must be better than glass, because it requires 
no additional shading. This covering confines the heat, and prevents 
the operation of the external air, so that if the frames are closed when 
there is no frost, it likewise prevents the escape of the heat, and keeps 
the covered subjects at the same temperature which prevailed when the 
frames were closed.* 
Mr. R. Thompson, of England, describes the following method of pro- 
tecting espaliers in unusually severe weather, peaches and nectarines be- 
ingin bloom atthetime. Attheend of March coping-boards were placed 
along the walls, and a network stretched over half of it, while straw 
sereens protected the other half at night; in severe nights the nets were 
the best protection. The screens consisted of one length of straw fixed 
on twine, and stretched between training rods one inch square and 
six feet long; they were kept in place by fixing the tops of the rods 
against nails in the wall, the lower-pointed ends being inserted in the 
ground. By day the screens were rolled and laid at the bottom of the 
wall. The blossoms under these were protected, but those on the front 
of shoots above them were destroyed. Some of the latter, which were 
on the side of the shoots close to the wall, derived from it sufficient 
heat to keep them alive. On the whole a fair crop was saved. On pear 
walls the blossoms were abundant and mostly expanded. Coping-boards 
were used, in addition to nets, for walls with an eastern aspect. Elsewhere 
straw screens were projected from the tops of the walls. Under these 
the fruit on the upper branches, near the straw, was saved, but. that 
toward the bottoms of some trees was much injured. The crops averaged 
fair. A glazed peach frame was covered with mats, but still the blos- 
soms were mostly destroyed. 
The preceding observations show that straw screens will protect peach 
trees in blossom from the effects of 12° of frost; coping-boards will suf- 
Wfice for about 4°; common nets, aided by coping-boards, were not so 
efficient as scraw screens. Sashes placed nearly horizontal, covered with 
mats, with a three-inch opening at the bottom of the frame, and per- 
forated zinc-plates in front, were insufficient, the fruit under them sufier- 
ing as much as that on an open wall with coping-boards only. Straw 
being a very efficient material, probably from its hollow nature, and the 
quantity of air it contains, and also being a slow conductor of heat, 
should be manufactured in neat screens, so as to preserve its tubular 
form. t 
The following is Mr. John Harrison’s method for protecting wall fruit: 
A rod is placed horizontally under the coping of the wall; another is fixed 
on posts three feet from the bottom of the wall, and eighteen inches 
from the ground, and the two are connected by braces. A covering is 
prepared by sewing woolen netting on its upper and lower edges to 
coarse calico, and this is attached to the rods by tapes. The cost of the 
net is 1s. 8d. per yard; of the calico, 2d. or 24d. per yard, and each yard, 
slit down the middle and sewed to the netting, makes the covering three 
yards wide; the tape and poles are a small item, aud the entire cost in 
England, including making, is under 2s. per yard. 
Harrison’s walls are brick, eleven feet high, with a stone coping of 
two inches projecting on each side. His trees are unnailed before win- 
ter, and fastened loosely to the wall to prevent their being broken by 
the wind. They are kept thus until ready to burst into flower, the ob- 
ject being to retard vegetation as much as possible. They are dressed 
with the following composition: equal parts of sulphur vivam, Scotch 
*The Gardener and Practical Florist. London, 1844, vol. iii, pp. 378, 379. 
t Journal of the Horticultural Society. London, 1852, pp. 207, 208. 
