442 
plii^t's natural history. 
[Book XVII. 
critical four days for the olive, being the period at which the 
south wind, as we have already^^ stated, brings on its dark and 
lowering clouds. The cereals, too, ripen more unfavourably 
when south winds prevail, though at the same time it pro- 
ceeds with greater rapidity. All cold, too, is injurious to ve- 
getation, which comes with the northern winds, or out of the 
proper season. It is most advantageous to all plants for 
north-east winds^^ to prevail throughout the winter. 
In this season, too, showers are very necessary, and the rea- 
son is self-evident — the trees, being exhausted by the fruit 
they have borne, and weakened by the loss of their leaves, are, 
of course, famished and hungry ; and it is the showers that 
constitute their aliment. Experience has led us to believe 
that there is nothing more detrimental than a warm winter ; 
for it allows the trees, the moment chey have parted with 
their fruits, to conceive again, or, in other words, to germinate, 
and then exhaust themselves by blossoming afresh. And 
what is even worse than this, should there be several years of 
such weather in succession, even the trees themselves will die ; 
for there can be little doubt that the effort must of necessity 
be injurious, when they put forth their strength, and are at 
the same time deprived of their natural sustenance. The poet^^ 
then, who has said that serene winters are to be desired, cer- 
tainly did not express those wishes in favour of the trees. 
And no more does rain, if prevalent at the summer-solstice, 
conduce to the benefit^^ of the vine : while, at the same time, 
to say that a dusty winter produces a luxuriant harvest, is cer- 
tainly the mistake of a too fertile imagination. It is a thing 
greatl^T" to be wished, too, both in behalf of the trees as well as 
the cereals, that the snows should lie for a considerable time 
upon the ground ; the reason being that they check the escape 
of the spirit of the earth by evaporation, and tend to throw it 
18 See B. xvi. c. 46. 
19 From Theophrastus, De Causis, B. ii. c. 1. 
20 He alludes to the words of Yirgil, Georg. i. 100 : — 
''Humida solstitia, atque hiemes orate serenas, 
Agricoloe; hiberno lagtissima pulvere farra." 
Fee remarks, that the cultivators of the modern times are more of the 
opinion of the poet than the naturalist. 
-1 Because rains would cause the young fruit to fall off. He here 
attacks the first portion of the precepts of Virgil ; hut only, it appears, in 
reference to the vine 
