is thereby acquired-, which fcorches the tender flowers, 
and other parts of plants. 
But that blights are frequently no more than an in- 
ward weaknels or diftemper in trees, will evidently 
appear, if we consider how often it happens, that 
trees againft the fame wall, expofed to the fame afpedt, 
and equally enjoying the advantages of fun and air, 
with every other cireumftance which might render 
them equally healthy, yet very often are obferved to 
differ greatly in their ftrength and vigour ; and as 
often we obferve the weak trees to be continually 
blighted, when the vigorous ones, in the fame fi- 
tuation fhall efcape very well ; which mnft, therefore, 
in a great meafure, be afcribed to their healthy con- 
ftitution. This weaknefs, therefore, in trees, mull 
proceed either from a want of a fufficient fupply of 
nourifhment to maintain them in perfedt vigour, or 
from fome ill qualities in the foil where they grow, 
or, perhaps, from fome bad quality in the flock, or 
inbred diftemper of the buds or cyons, which they 
had imbibed from their mother tree, or from miff 
management in the priming, &c. all which are pro- 
ductive of diflempers in trees, and of which they are 
with difficulty cured. Now, if this is occafioned by 
a weaknefs in the tree, we fhould endeavour to trace 
out the true caufe ; firft, whether it ha,s been oc- 
cafioned by ill management in the pruning, which 
is too often the cafe ; for how common is it to obferve 
Peach-trees trained up to the full length of their 
branches every year, fo as to be carried to the top of 
the wall in a few years after planting, when at the fame 
time the flioots for bearing have been fo weak, as 
fcarcely to have ftrength to produce their flowers: but 
this being the utmoft of their vigour, the bloffoms fall 
off, and, many times, the branches decay, either the 
greateft part of their length, or quite down to the 
place where they were produced ; and this, whenever 
it happens to be the cafe, is afcribed to a blight. 
Others there are, who fuffer their trees to grow juft 
as they are naturally difpofed, during the fummer 
feafon, without flopping of fhoots, or difburdening 
their trees of luxuriant branches ; by which means 
two, three, or four fhoots fhall exhauft the greateft 
part of the nourifhment of the trees all the fummer 
which fhoots, at the winter pruning, are entirely cut 
out ^ fo that the ftrength of the tree was employed 
only in nourifhing ufelefs branches, while the fruit 
branches are thereby rendered fo weak, as not to be 
able to preferve themfelves. The remedies to this 
evil fhall be explained in the article of Pruning 
Peach-trees, &c. 
But if the weaknefs of the tree proceeds from an in- 
bred diftemper, it is the better way to remove the 
tree at firft and after renewing your earth, plant a 
new one in its place. 
Or if your foil be a hot burning gravel or fand, in 
which your Peach-trees are planted, you will gene- 
rally find this will be conftantly their cafe, after their 
roots have got beyond the earth of your borders ; for 
which reafon, it is much more advifeable to dig them 
up, and plant Grapes, Figs, Apricots, or any other 
fort of fruit, which may do well in fuch a foil, rather 
than to be annually difappointed of your hopes ; for, 
by a variety of experiments, it hath been found, that 
Apricots attract and imbibe moifture with a much 
greater force than Peaches and Nedtarines and con- 
fequently, are better able to attradt the nutritive par- 
ticles from the earth, than the other, which require 
to be planted in a generous foil, capable of affording 
them a fufficiency of nourifhment without much dif- 
ficulty : and it is in filch places we often fee Peaches 
do wonders, efpecially if affifted by art ; but as for 
the Vine and Fig-tree, they perfpire very flowly, 
and are very often in an imbibing ftate (fo that a 
great part of that fine racy flavour, with which their 
fruits abound when planted in a dry foil, is probably 
owing to thofe refined aerial principles, which are 
coffecied when in a ftate of refpiration ;) and there- 
fore, as thefe trees delight not in drawing much 
watery nourifhment from the earth, fo they will much 
7 
better iucceed in fuch a foil, than in one that is mori 
generous : we fhould therefore always endeavour to 
fait the particular forts of fruits to the nature of our 
foil, and not pretend to have ail forts of fruit good in 
the fame. 
But there is another fort of blight, againft which it 
is very difficult to guard our fruit-trees - 5 this is iffiarp, 
pinching, frofty mornings, which often happen at the 
time when the trees are in flower, or while the fruit 
is very young, and occafion the bloffoms or fruit to 
drop off ; and, fometimes, the tender parts of the 
flioots and leaves are greatly injured thereby. 
The only method yet found out to prevent this miff 
chief, is, by carefully covering the walls, either with 
mats, canvas, reeds, &c. which being faftened fo as 
not to be difturbed with the wind, and fuffered to 
remain on during the night, and taking them off 
every day, if the weather permits, is the beft and 
fureft method that hath yet been found fuccefsful ; 
which, although it has been flighted, and thought 
of little fervice by fome, yet the reafon of their being 
not fo ferviceable as has been expedted, was, becaufe 
they have not been rightly ufed, either by ftiffering 
the trees to remain too long covered by which means 
the younger branches and leaves have been rendered 
too weak to endure the open air, when they are ex- 
pofed to it j which has often proved of worfe con- 
fequence to trees, than if they had remained entirely 
Uncovered, or by incautioufly expofing them to, the 
air, after having been Jo nr.- covered. 
Whereas, when the covering before-mentioned has 
been performed as it ought to be, it has proved very 
ferviceable to fruits j and many times, when there 
has been almoit a general deftruction of fruits in the 
neighbouring gardens, there has been a plenty of 
them in fuch places where they have been properly 
covered : and though the trouble may feem to fome 
' very great, yet, if thefe coverings are fixed near the 
upper part of the wall, and are faftened to pullies, 
fo as to be drawn up, or let down, it will be foon and 
eafily performed-, and the fuccefs will fufficiently re- 
pay the trouble. 
But there is another fort of blight that jpmetimeg 
happens later in the fpring, viz. in April or May, 
which is often very deftrudtive to orchards, and open 
plantations, and againft which we know of no remedy. 
This is what is called a fire blaft ; which, in a few 
* hours, hath not only deftroyecl the fruit and leaves, 
but, many times, parts of trees, and, fometimes, 
entire trees have been killed by it. 
This is fuppofed to be effedted by volumes of tranff 
parent flying vapours, which, among the many forms 
they revolve into, may fometimes approach fo near 
to an hemifphere, or hetnicylinder, either in their 
upper or lower furfaces, as thereby to make the 
beams of the fun converge enough to fcorch the plants 
or trees they fall upon, in proportion to the greater 
or lefs convergency of the fan’s rays. 
The learned Boerhaave, in his Theory of Chemiftry, 
obferves, 44 That thofe white clouds which appear in 
44 fummer time, are, as it were, fo many mirrors, 
44 and occafion exceffive heat : thefe cloudy mirrors 
44 are fometimes round, fometimes concave, poly- 
44 gonous, &c. When the face of the heavens is co- 
44 vered with fuch white clouds, the fun, ffiining 
44 among them, muff, of neceftity, produce a ve~ 
44 hement heat-, fince many of his rays, which would 
44 otherwife, perhaps, never touch our earth, are 
44 hereby reflected to us : thus,' if the fun be on one 
44 fide, and the clouds on the oppofite one, they will 
44 be perfect burning glaffes : and hence the phsno- 
44 menon of thunder. 
44 I have fometimes, continues he, obferved a kind 
“ of hollow clouds, full of hail and fnow, during 
44 the continuance of which the heat was extreme ; 
44 fince, by fuch condenfation, they were enabled to 
44 reflect much more ftrongly : after this came a fharp 
44 cold, and then the clouds difeharged their hail in 
44 great quantities, to which fucceeded a moderate 
44 warmth. Frozen concave clouds therefore, by 
44 their 
