156 Rtiffi7i^s Essay on Calcareous Manures. 



Art. VII. An Essay on Calcareous Manures. By Edmund Ruffin. 

 Small 8vo, pp. 242. Petersburg, Lower Virginia, 1832. 



The object of this essay, Mr. Ruffin informs us, is to in- 

 vestigate the peculiar features and qualities of the soils of the 

 tide-water districts of Lower Virginia ; " to show the causes of 

 their general unproductiveness; and to point out means, as yet 

 but little used, for their effectual and profitable improvement." 

 The sterility of these soils Mr, Ruffin has ascertained to arise 

 from their being destitute of calcareous earth, and from their being 

 injured by the presence of vegetable acid. 



After two chapters on earths and soils generally, and on the 

 soils and state of agriculture in the tide-water districts of 

 Virginia, the author treats of the different capacities of soils for 

 improvements, and discusses the following propositions : — 



1. " Soils naturally poor, and rich soils reduced to poverty by cultivation, 

 are essentially different in their powers of retaining putrescent manures : and, 

 under like circumstances, the fitness of any soil to be enriched by these 

 manures, is in proportion to what was its natural fertility. 



2. " The natural sterility of the soils of Lower Virginia is caused by such 

 soils being destitute of calcareous earth, and their being injured by the pre- 

 sence and effects of vegetable acid. 



3. " The fertilising effects of calcareous earth are chiefly produced by its 

 power of neutralising acids, and of combining putrescent manures with soils, 

 between which there would otherwise be but little, if any, chemical at- 

 traction. 



4. " Poor and acid soils cannot be improved durably or profitably, by 

 putrescent manures, without previously making them calcareous, and thereby 

 correcting the defect in their constitution. 



5. " Calcareous manures will give to our worst soils a power of retaining 

 putrescent manures equal to that of the best ; and will cause more productive- 

 ness, and yield more profit, than any other improvement practicable in Lower 

 Virginia." (p. 30.) 



These propositions contain the marrow of the essay, which 

 is closely reasoned, and, in several particulars, original. Mr. 

 Ruffin has the merit of first pointing out that there can be no 

 such thing as a naturally fertile soil, without the presence of 

 calcareous earth; but, where this earth is present, the soil, 

 however exhausted it may have been by culture, will, when left 

 to itself, after a time regain its original fertility : that soils which 

 contain no calcareous earth are never found naturally fertile, 

 except masses or beds of vegetable matter, which are not pro- 

 perly soils : and that all that art can do to them, exclusive of 

 adding calcareous earth, is, to force crops by putrescent manures ; 

 but that, when these manures are withheld, the soil will speedily 

 revert to its original sterility. Mr. Ruffin observes that no 

 agricultural or chemical writer ever denied these facts ; but he 

 assisrts, and we think with truth, that by not one of them have 

 they ever been distinctly stated. We are not quite certain as to 

 Grisenthwaite, but we are so as to Kirwan, Dundonald, Davy^ 



