ASSERTIONS OP CALX IN SOIL BEING USUAL. 51 



a soil which contained thirty-one per cent, of calcareous earth, and 

 he supposes that proportion neither too little nor too much.* 

 Young mentions soils of extraordinary fertility containing seventeen 

 and twenty per cent., besides others with smaller proportions of 

 calcareous earth and says that Bergman found thirty per cent. 

 in the best soil he examined. f Ilozier speaks still more strongly 

 for the general diffusion and large proportions of this ingredient 

 of soils. In his general description of earths and soils, he gives 

 examples of the supposed composition of the three grades of soils 

 which he designates by the terms rich, good) and middling soils; to 

 the first class he assigns a proportion of one-tenth, to the second, 

 one-fourth, and to the last, one-half of its amount, of calcareous 

 earth. The fair interpretation of the passage is that the author 

 considered these large proportions as general, in France and he 

 gives no intimation of any soil entirely without calcareous earth. J 



The position assumed above, of the general or universal concur- 

 rence of former European authors in the supposed general presence 

 of calcareous earth in soils, could be placed beyond dispute by ex- 

 tracts from their publications. But this would require many and 

 long extracts, too bulky to include here, and which cannot be fairly 

 abridged, or exhibited by a few examples. No author says directly, 

 indeed, that calcareous earth is present in all soils; but its being 

 always named as one of the ingredients of soils in general, and no 

 cases of its absolute deficiency in tilled lands being directly stated, 

 amount to the declaration that calcareous earth is very rarely, if 

 ever, entirely wanting in any soil. We may find enough directions 

 to apply calcareous manures to soils that are deficient in that in- 

 gredient ; but that deficiency seems to be not spoken of as absolute, 

 but relative to other soils more abundantly supplied. In the same 

 manner, writers on agriculture direct clay, or sand, to be used as 

 manure for soils very deficient in one or the other of those earths; 

 but without meaning that any soil under cultivation can be found 

 entirely destitute of sand or of clay. My proofs from general 

 treatises would therefore be generally indirect ; and the quotations 



*Kirwan on Manures, article " Clayey Loam." 



f Young's Essay on Manures. 



J " Composition of soils. Examples of the various composition of soils: 

 Kick soil; silicious earth, 2 parts; aluminous, 6; calcareous, 1 ; vegeta- 

 ble earth, [humus'] 1 ; in all, 10 parts. Good soil silicious, 3 parts ; 

 aluminous, 4; calcareous, 2J; vegetable earth, J of 1 part; in all, 10 

 parts. Middling soil [sol mediocre ;] silicious, 4 parts; aluminous, 1; cal- 

 careous, 5 parts, less by some atoms of vegetable earth ; in all, 10 parts. 

 We see that it is the largest proportion of aluminous earth that constitutes 

 the greatest excellence of soils ; and we know that independently of their 

 harmony of composition, they require a sufficiency of depth." Translated 

 from" the article " Terres" in the "Cours Complet d' Agriculture Pratique, 

 etc. par 1'Abbe llozicr," 1815. 



