110 
THE FLORIST. 
exterior ones, and the sashes will also slide, to allow of a circulation 
from one division to the other. An air-flue will also be required, to 
run on each side the main division wall from north to south, and com¬ 
municating with openings at the back and front of the building. These 
air-flues should be 18 or 20 inches wide, and three feet deep, and a 
hot-water pipe may be laid along their bottom ; the object is to supply 
a current of air down the centre of the house, farthest removed from the 
sides, where the ventilation is more ample; openings every six or eight 
feet will be brought from the air-drain by shafts elevated two feet 
above the level of the border, and these shafts will cause a good draught 
of air to enter the house at points where it is most needed to produce 
internal circulation. It will scarcely be necessary to increase these ; but 
should they be found inadequate the principle may be carried to any 
extent, with this caution—that as a current of cold air passing into 
the house underneath would in some measure chill the borders, it will 
be desirable to make the air-drains of hollow bricks, or build a double 
wall, with a three-inch area between the sides ; this will prevent the 
cold air, in passing down the flue, from chilling the border. The pipe 
on the bottom will help to rarify the air, and cause a r apid draught; 
the valves, or trap-doors to regulate the admission, should be at the 
end openings, and may be worked in a very simple manner. 
(To be continued.) 
PROTECTING FRUIT-TREES IN SPRING. 
Although much has appeared in the pages of the Florist on this 
subject, no very satisfactory conclusion could be arrived at; the advo¬ 
cates for protection being nearly equal to those entertaining an opposite 
opinion, rendered it difficult for the amateur to decide which course to 
adopt. As the season is now at hand when a reconsideration of the 
subject may be useful, the following remarks may not, perhaps, be out 
of place. 
First, it may be well to consider what amount of injury the trees are 
liable to receive from spring frosts, the reason a crop of fruit is lost by 
covering, and the proper way to use covering to ensure a crop. 
The greatest injury from frost mostly happens in April; at that time 
we often get strong sunshine through the day, followed by sharp frost 
at night, therefore a rapid transition from heat to cold occurs, which is 
extremely injurious to wall trees, more especially the Peach; and in 
southern aspects (where this fruit is mostly grown), the warm sun 
through the day excites the trees, and causes the upward flow of sap to be 
thin and active, flowing to the extremities of the branches, and while the 
sap-vessels are charged with fluid they are frozen at night, which 
being repeated ruptures the sap-vessels, and disease soon after shows 
itself in small black spots on the young wood, which soon shrivels and 
dies, and if the tree has been seriously affected the poisoned sap is 
carried by the downward current through the entire tree, which often 
ends in its death. The Pear is also very liable to injury from the same 
cause, which is commonly termed canker; and if Peach-trees can be 
