iv PREFACE TO THE FIFTH EDITION. 



soils while, from all existing testimony of preceding writers on 

 agriculture, the very general, if not universal prevalence of carbo- 

 nate of lime would have been inferred by every reader. 



3. The general presence of some vegetable acid in all our natu- 

 rally poor soils, and this acid acting as a cause of sterility. 



4. The application of carbonate of lime to soils deficient in that 

 necessary element, serving to neutralize the acid and, by that and 

 other stated and important operations or effects, serving to fit the 

 before poor and unimprovable soils for speedy and profitable 

 improvement. 



These positions were assumed and maintained in all the different 

 editions of this essay, from 1821 to 1842.* For my own practice 

 they served, as soon as impressed on my mind, to direct and 

 enjoin, as indispensable for any important and remunerating im- 

 provement of poor soils, the application of calcareous manures; 

 and especially of the cheapest and most abundant resources in this 

 region, the beds of fossil-shells (or marl), then scarcely noticed, 

 and not used in any known practice. 



My just claim to the actual introduction in this country of this 

 now wide-spread and most beneficial means for fertilization, and 

 my making generally known the value, and inducing the later 

 numerous and extensive applications by many other farmers, has 

 not been openly disputed. Detractors in wish and intention have 

 indeed thought that they had plucked from me some borrowed 

 plumes, when stating that numerous older writers (in Europe) had 

 recommended marling that thousands of farmers in Europe had 

 thus improved land and that, even in this country, some few 

 persons had tried disintegrated fossil shells as manure, and, in still 

 fewer cases, with success. Such facts, as to European opinions 

 and practice, have been long and well known to all reading 

 farmers ; and it would have been impossible, if I had desired it, 

 to shut out this information. The trials in America were so 

 limited, and so little known (and of which but one case had then 

 appeared in print, and that later than my earliest practice, in 1818), 

 that not one of them had reached me until after my opinions had 

 been formed and uttered, and my practice, founded thereupon, had 

 been commenced and was in progress. And when these cases were 

 subsequently heard of, I industriously sought to gather the facts ; 

 and have published them all, at length, in the former editions of this 

 work. But, in truth, none of these prior practices, or opinions 



* The principal and more important of these opinions had been asserted 

 as early as 1818, in a communication to the Prince George Agricultural 

 Society. But as that communication (-which was the first concise sketch, 

 since enlarged to this Essay) was not then printed, perhaps I may have no 

 right to cite it as showing so early a date for my claims of discovery. An 

 extract from that communication will be embraced in one of the pieces in 

 the Appendix. 



