Chap. 3.] WHAT SOILS AEE BEST. 447 



thing that is proved in the case of the argillaceous earths. 33 

 The earth when thrown back into the hole from which it has 

 just been dug will never 34 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 35 soil, without exception, 

 will cover iron with rust. Nor yet can we determine 36 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 37 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 : 38 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, :;9 



33 He alludes to the difficulty with which argilla, from its tenacity, is 

 employed in cultivation. 



34 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. 



36 In allusion to what Virgil says, Georg. ii. 254 : — 



"Quae gravis est, ipso tacitam se pondere prodit, 



Quaeque 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. 



37 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. 



38 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. 



3<J " Tophus ;" formed of volcanic scoriae. Fee remarks, that it is some- 



