COLLECTIONS AND RECOLLECTIONS. 
319 
The Aphides injure all the varieties of plum, and a Coccus some¬ 
times abounds in such quantities on those trees, that in summer 
every twig is thickly beaded with little red half-round specks. In 
spring, the larvae exhaust the trees, by sucking out the rising sap. 
The grub of a little brown beetle destroys the blossom of the pear- 
tree, and a saw-fly injures the fruit so as to cause it to drop prema¬ 
turely. In short, almost every kind of fruit-tree has its family of 
grubs, which, in their larva state prey on the sap, the leaves, or the 
flower-buds; and to prevent this, the above recipe is intended. — 
The apple-aphis or American blight may be destroyed by smearing 
the parts infected with spirits of turpentine or oil. This enemy of 
the apple-tree was not known till the year 1787; it is a very mi¬ 
nute insec t, covered with a long cotton-like wool, and fixes itself in 
the chinks and rough parts of the bark. C. C. C C. 
Remarks on the Economical Application of Heat, in 
Forcing. —The economical application of heat produced by fer¬ 
mentation for the purposes of forcing, is, to all persons, but more 
particularly to those possessing small gardens, of great importance, 
which I doubt not your Register will be the ready means of impart¬ 
ing, to those like myself wishing to become better acquainted there¬ 
with. The articles of Mr. Waldron, Yol. 1, page 399, and Yol. 2, 
page 63; Mr. Knowlys, Yol. 2, page 12, and Mr. Reynolds, page 13, 
shew considerable difference in the economic application of heat; 
the two former applying the dung in trenches, Mr. W. using loose 
stones at the bottom of the pit, for the purpose of retaining the heat, 
and Mr. Knowlys a chamber for the like purpose, whilst Mr. Rey¬ 
nolds makes a solid bed five feet thick, similar to those used for re¬ 
ceiving cucumbers. Tiie latter appears to me to be the most expen¬ 
sive method, and Mr. Waldron’s the best. But the object of my 
troubling you, is to learn which of the first two methods is the best, 
for beginners like myself, between several methods, are often puzzled 
which to apply. Mr. Knowlys does not state what material he uses 
for supporting the spent bark in the pit, and preventing its falling 
into the air-chamber beneath, and whether it is perforated with 
holes to enable the heat to communicate readily with the bed. 
H ORTIC U LT U Rl ST. 
February 1 6th, 1833. 
Our draughtsman made an important error in the plan and section of the pit, 
recommended by Mr. Knowlys, which will be rectified by another engraving in 
our next. We had intended it for this month, but the cut not being ready, we 
were unable to do so. Conductor, 
