414 EUROPEAN AGRICULTURE. 



it is well known that, when the volcanic ashes have been exposed 

 for some time to the influence of air and moisture, a soil is grad 

 ually formed in which all kinds of plants grow with the greatest 

 luxuriance. This fertility is owing to the alkalies which are 

 contained in the lava, and which, by exposure to the weather, 

 are rendered capable of being absorbed by plants. Thousands 

 of years have been necessary to convert stones and rocks into 

 the soil of arable land ; and thousands of years more will be 

 requisite for their perfect reduction that is, for the complete 

 exhaustion of their alkalies.&quot; 



This is a very extraordinary statement, and, without implying 

 any distrust of the authority on which it is made, is certainly 

 not consonant to general experience. General experience would 

 seem to show that soils without any vegetable mould are not 

 productive, and most practical farmers would prefer, of all others, 

 a soil where the vegetable matter, well compounded, existed in 

 abundance, forming, as it is termed, a deep and rich loam. But 

 it would seem that, in the case to which Liebig refers, thousands 

 of years are necessary to render a mass of lava fertile, and in 

 such a case it might be fairly presumed that some vegetable 

 matter might accumulate and produce the desired mixture. I 

 do not presume to call in question an authority so distinguished, 

 and for which no man has more respect than myself; but I 

 could wish that we had more facts in the case, or that they were 

 more definitely stated. 



Until recently, almost all agriculturists, both the scientific and 

 practical, have considered the quantity of vegetable matter 

 contained in a soil as the test of its fertility. A prejudice so 

 universal, and so long established, would seem, on those grounds, 

 strongly entitled to respect. It has been as well understood 

 that vegetable matter alone, as in the case of peat, and this but 

 partially decomposed, was not fertile. But the opinion of the 

 connection of vegetable mould with fertility applied to vege 

 table matter in a state of comminution and intermixture with 

 other elements of a soil, and here the fertility of the land has 

 been understood to bear a very close relation to its predominance 

 or deficiency. Peat itself, when thoroughly decomposed, has 

 been found a most efficient manure. The effects constantly 

 accruing from the application of decayed vegetable matter to the 



