and the Method of making Wines. 183 
impedes the free passage of the air and water, and by 
these means maintains around the roots a putrid moisture 
which tends to corrupt them. The fanners, therefore, 
carefully avoid planting vines in situations exposed in 
wind : they prefer calm situations, well sheltered, where 
the plants may be exposed only to the benign influence of 
the luminary towards which they are placed. 
Fogs are also exceedingly dangerous to the vine : they 
are destructive to the blossoms, and do essential hurt to 
the grapes. Besides the putrid miasmata, which they too 
often deposit on the productions of the fields, they are 
always attended with the inconvenience of moistening 
the surfaces, and of forming on them a stratum of water, 
more subject to evaporation, as the interior of the plant 
and the earth are not moistened in the same proportion; 
so that the rays of the sun, falling upon this light stratum 
of moisture, cause it to evaporate in an instant ; and the 
sensation of coolness, determined by the act of evapora- 
tion, is succeeded by a heat the more prejudicial as the 
transition is abrupt. It very often happens that the clouds 
suspended in the atmosphere, by concentrating the rays 
of the sun, direct them towards parts of the vines, by 
which means they are burnt. In the scorching climates 
of the south, it is sometimes observed that the natural heat 
of the soil, strengthened by the reverberation from cer- 
tain rocks, or whitish kinds of soil, dries up the grapes 
exposed to them. 
Though heat be necessary for ripening the grapes, giv- 
ing them a saccharine taste and a good flavour, it would 
be erroneous to believe that its action alone can produce 
every effect required. It can be considered only as a 
mean necessary for maturation, which supposes that the 
earth is sufficiently furnished with the juices that ought 
to supply the materials. Heat is necessary ; but this heat 
must not be exercised on dried earth, for in that case it 
