Chap. 3.] 
WHAT SOILS ARE BEST. 
447 
thicg that is proved in the case of the argillaceous earths.^^ 
The earth when thrown back into the hole from which it has 
just been dug will never fill it, so that it is quite impossible 
by that method to form any opinion as to its density or thin- 
ness. It is the fact, too, that every soil, without exception, 
will cover iron with rust. Nor yet can we determine the 
heaviness or lightness of soils in relation to any fixed and as- 
certained weight : for what are we to understand as the 
standard weight of earth ? A soil, too, that is formed from 
the alluvion of rivers is not always to be recommended, for 
there are some crops that decay all the sooner in a watery soil ; 
indeed, those soils even of this description which are highly 
esteemed, are never found to be long good for any kind of 
vegetation but the willow. 
Among other proofs of the goodness of soil, is the comparative 
thickness of the stem in corn. In Laborium, a famous cham- 
paign country of Campania, the stalk is of such remarkable 
thickness, that it may be used even to supply the place of 
wood and yet this very soil, from the difficulty that is every- 
where experienced in cultivating it, and the labour required 
in working it, may be almost said to give the husbandman 
more trouble by its good qualities than it could possibly have 
done by reason of any defects. The soil, too, that is generally 
known as charcoal earth, appears susceptible of being im- 
proved by being planted with a poor meagre vine : and tufa,'-^ 
23 He alludes to tke difficulty with which argilla, from its tenacity, is 
employed in cultivation. 
2^ Columella says the contrary, and so does Yirgil, Georg. ii. 226, 
speaking of this fact as a method of ascertaining the respective qualities of 
the earth. 
35 Virgil, Georg. ii. 220, says the contrary. 
^'^ In allusion to what Virgil says, Georg. ii. 254 : — 
" Quae gravis est, ipso tacitam se pondere prodit, 
Quseque levis " 
Fee remarks, however, that it is easy enough to analyse the earth, and 
ascertain the proportions of humus, and of the siliceous, cretaceous, or 
argillaceous earths ; the relative proportions of which render it strong or 
light, as the case may be. 
As Fee says, these earths vary according to the nature of the soils 
that are brought down by the streams ; in general, however, they are ex- 
tremely prolific. 
2^ Fee says that Pliny is here guilty of some degree of exaggeration. 
See B. iii. c. 9, p. 195 of Vol. 1 : also B. xviii. c. 29. 
^'"^ " Tophus formed of volcanic scoriae. Fee remarks, that it is some- 
