As the effects of heat are seldom very remarkable in the northerly
climate of England, where the summers are often so defective in warmth
and sunshine as not to ripen the fruits of the earth so well as might be
wished, I shall be more concise in my account of the severity of a summer
season, and so make a little amends for the prolix account of the degrees
of cold, and the inconveniences that we suffered from some late rigorous
winters.
The summers of 1781 and 1783 were unusually hot and dry; to them
therefore I shall turn back in my journals, without recurring to any more
distant period. In the former of these years my peach and nectarine
trees suffered so much from the heat that the rind on the bodies was
scalded and came off; since which the trees have been in a decaying
state. This may prove a hint to assiduous gardeners to fence and shelter
their wall-trees with mats or boards, as they may easily do, because such
annoyance is seldom of long continuance. During that summer also, I
observed that my apples were coddled, as it were, on the trees; so that
they had no quickness of flavour, and would not keep in the winter. This
circumstance put me in mind of what I have heard travellers assert, that
they never ate a good apple or apricot in the south of Europe, where the
heats were so great as to render the juices vapid and insipid.
The great pests of a garden are wasps, which destroy all the finer fruits
just as they are coming into perfection. In 1781 we had none; in 1783
there were myriads, which would have devoured all the produce of my
garden, had not we set the boys to take the nests, and caught thousands
with hazel-twigs tipped with bird-lime: we have since employed the boys
to take and destroy the large breeding wasps in the spring. Such
expedients have a great effect on these marauders, and will keep them
under. Though wasps do not abound but in hot summers, yet they do not
prevail in every hot summer, as I have instanced in the two years above
mentioned.
In the sultry season of 1783, honey-dews were so frequent as to deface
and destroy the beauties of my garden. My honeysuckles, which were one
week the most sweet and lovely objects that the eye could behold, became
the next the most loathsome; being enveloped in a viscous substance, and
loaded with black aphides, or smother-flies. The occasion of this clammy
appearance seems to be this, that in hot weather the effluvia of flowers
in fields and meadows and gardens are drawn up in the day by a brisk
evaporation, and then in the night fall down again with the dews, in
which they are entangled; that the air is strongly scented, and therefore
impregnated with the particles of flowers in summer weather, our senses
will inform us; and that this clammy sweet substance is of the vegetable
kind we may learn from bees, to whom it is very grateful: and we may be
assured that it falls in the night, because it is always first seen in
warm still mornings.
On chalky and sandy soils, and in the hot villages about London, the
thermometer has been often observed to mount as high as 83 degrees or 84
degrees; but with us, in this hilly and woody district, I have hardly
ever seen it exceed 80 degrees, nor does it often arrive at that pitch.
The reason, I conclude, is, that our dense clayey soil, so much shaded by
trees, is not so easily heated through as those above-mentioned; and,
besides, our mountains cause currents of air and breezes; and the vast
effluvia from our woodlands temper and moderate our heats.