PREFACE TO THE FIFTH EDITION. 



THE publication of another edition of this Essay was not 

 designed to be made during the life of the author, until recent 

 circumstances served to induce a change of purpose. When. 

 closing my publication of the "Farmers' Register" -to which 

 service I had devoted and (in reference to my own interest) sacri- 

 ficed the ten best years of my life I had withdrawn from all 

 connexion with the public, and had no thought of again leaving 

 the quiet seclusion which I had sought and found. But though 

 not expecting again to appear in print during my life, it was 

 nevertheless my practice to make corrections of this Essay, and to 

 prepare materials for future emendations and additions, as new 

 lights were afforded by extended observation and investigation, or 

 by my still extending practical experience. This labour was due 

 to my own reputation. Further, I trusted that, when the results 

 should finally be offered to my countrymen, this and also other 

 previous services might be the more justly appreciated, because 

 the author would then be beyond the reach of applause or recom- 

 pense. Thus, at different and irregular times, separated by long 

 intervals of cessation of this particular labour, this edition was 

 prepared for posthumous publication. And though the publication 

 is now advanced in time, the before-designed form and manner 

 are not changed, except in the making of still later additions and 

 corrections. 



Under all the existing circumstances, I trust it will not be 

 deemed improper, or offensively egotistical, for me, at this time 

 and in plain words, to assert my just claim to the most important 

 of the truths which were first announced in the earliest and also 

 in every subsequent edition of this Essay; and which truths, 

 though having formerly no other support than my obscure name, 

 are now so generally accepted and recognised, that they may seem 

 to have been long established and undisputed. Among these 

 opinions, or facts, which I was the first to distinctly assert, and to 

 maintain at length by proof and argument, were the following : 



1. The capacity of impoverished soils for receiving improve- 

 ment from putrescent manures, being in proportion to their origi- 

 nal or natural measures of fertility ; and that soils naturally poor 

 (especially in this country) could not be enriched by these manures, 

 durably or profitably, above their natural degree of productive- 

 ness. 



2. The almost universal and total absence of carbonate of lime 

 in the soils of the Atlantic slope of Virginia, and (by inference) 

 of most others of the United States and even in most lime-stone 



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