446 
plii^y's natural histoet. 
[Book XVir. 
will gain nothing by approaching closer to its saline exhala- 
tions. The same, too, is the influence exercised by rivers and 
lakes ; they will either scorch the vegetation by the fogs they 
emit, or else modify by their coolness the excess of heat. We 
have already mentioned the plants that thrive in the shade, 
and in the cold even ; but in all these matters experience will 
be found the best of guides. 
CHAP. 3. WHAT SOILS ARE TO BE CONSIDERED THE BEST. 
Kext after the influences of the heavens, we have to treat of 
those of the earth, a task that is in no way more easy than the 
previous one. It is but rarely that the same soil is found 
suited to trees as well as corn : indeed, the black earth which 
prevails in Campania is not everywhere found suited to the vine, 
nor yet that which emits light exhalations, or the red^^ soil 
that has been so highly praised by many. The cretaceous earth 
that is found in the territory of Alba Pompeia, and an argil- 
laceous soil, are preferred to all others for the vine, although, 
too, they are remarkably rich, a quality that is generally looked 
upon as not suited to that plant. On the other hand, again, 
the white sand of the district of Ticinum, the black sand of 
many other places, and the red sand as well, even though mixed 
with a rich earth, will prove unproductive. 
The very signs, also, from which we form our judgment are 
often very deceptive ; a soil that is adorned with tall and 
graceful trees is not always a favourable one, except, of course, 
for those trees. "What tree, in fact, is there that is taller than 
the fir ? and yet what other plant could possibly exist in the 
same spot ? E"or ought we always to look upon verdant pas- 
tures as so many proofs of richness of soil ; for what is there 
that enjoys a greater renown than the pastures of Germany ? 
and yet they consist of nothing but a very thin layer of turf, 
with sand immediately beneath. JNTor yet is the soil which 
produces herbage of large growth always to be looked upon as 
humid ; no, by Hercules ! no more than a soil is to be looked 
upon as unctuous and rich, which adheres to the fingers — a 
29 B. xvi. cc. 30, 31. 
^0 A rich black mould, probably. 
A ferruginous argilla. 
22 It must of necessity denote a soil rich in humus, though not, of 
course, adapted for all kinds of cultivation. 
