32 CALCAREOUS MANURES— THLORY 



of which he states the constitutent parts, obtained by chemical analysis, as 

 well as those reported by Kirwan, and by Young, all contain some propor- 

 tion (and generally a large proportion) of calcareous earth.* Kirwan states 

 the component parts of a soil which contained thirty-one per cent, of calca- 

 reous earth, and he supposes that proportion neither too little nor too much.f 

 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 tliirty per cent, in the best soil he ex- 

 amined.]; Rozier speaks stUl 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 mid- 

 dling 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. 5 



The position assumed above, of the general or universal concurrence of 

 former European authors in the supposed general presence of calcareous 

 earth in soils, could be placed beyond dispute by extracts from their publi- 

 cations. But this would require many and long extracts, too bulky to in- 

 clude here, and which cannot be fairly abridged, or exhibited by a few ex- 

 amples. No author says directly, indeed, that calcareous eartli 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 di- 

 rectly 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 ingredient ; but 

 that deficiency seems to be not spoken of as dhsoluie, but relatice to other 

 soils more abundantly suiiplied. In the same manner, writers on agricul- 

 ture 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 necessary to exhibit them would show what had not been said, 

 rather than what had— and that they did not assert the absence of calca- 

 reous earth, instead of directly asserting its universal presence. Extracts 

 for this purpose, however satisfactory, would necessarily be too voluminous, 

 and it is well that they can be dispensed with. Better proof, because it is 

 direct, and more concise, will be furnished by quoting the opinions of a few 

 agriculturists of our own country, who were extensively acquainted with 

 European authors, and have evidently drawn their opinions from those 

 sources. These quotations will not only show conclusively that their 

 authors consider the received European doctrine to be that all soils are 

 more or less calcareous —but also, that they apply the same general cha- 



* Agr. Chem., Lect. 4 — Kirwan on Manures — and Young's Prize Essay on Manures. 



t Kirwan on Manures, article " Clayey Loam." 



I Young's Essay on Manures. 



§ " Composition of soils. Examples of the various com[)Osition of soils: Rich soil ; 

 silicious earth, 2 parts ; aluminous, 6 ; calcareous, 1 ; vegetable earth, [fmmus'\ 1 ; in 

 all, 10 parts. Good soil — silicious, 3 parts ; aluminous 4 ; calcareous 2^ ; vegetable 

 earth, J of 1 part; in all, 10 parts. Middling soil [sol mediocre;'] silicious, 4 parts; 

 aluminous, 1 ; calcareous, 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 harmoHy of com- 

 position, they require a sufficiency of depth." — Translated from the article " Terres," 

 in the " Cours Complet d'Agriculture Pratique, etc. par I'Abbe Rozier, 1815. 



