INTRODUCTION. 5 



maturity, and subsequent decomposition of vegetable and animal substances, and the 

 mutual relations subsisting between these and the earth and atmosphere, have drawn 

 upon Liebig the admiration of all Europe and America. 



It must, nevertheless, be owned that though generally adopted, the accuracy of 

 some of Liebig's results has been more than questioned by distinguished chemists in 

 Europe and the United States. The particulars of these and the effects of the several 

 agencies acting upon the life of vegetables and animals, will be found in the Encyclo- 

 paedia of Agriculture, arranged under various heads, such as, Soils, Humus, Carbon, 

 Oxygen, Azote or Nitrogen, Hydrogen, Ammonia, etc. 



Whilst agriculture has, within the last few years, been thus receiving such rich 

 tributes from abroad, many scientific investigators of the highest merit have been 

 zealously and successfully engaged in the United States, in experimental researches 

 which have added greatly to the stock of useful knowledge. Among these, it would 

 be signal injustice to pass unnoticed the names of Professors Jackson and Dana of 

 Massachusetts, who have devoted great attention to the analyses of soils, the chemical 

 composition and properties of humus as found in ordinary mould, and in peats and 

 bog-mud, the results of which have been published in the reports of the Agricultural 

 and Geological Surveys of Massachusetts, and in separate essays. Professors Rogers 

 and Booth of Philadelphia, the former in his Geological Report of New Jersey, and 

 the latter of Delaware, have furnished numerous and highly accurate analyses of the 

 valuable calcareous marls and green-sand deposits found so abundantly in the states 

 named, as well as in others of the middle and southern regions, together with much 

 information relative to the application of these inexhaustible agents of fertility ; Nor 

 can we omit the name of Dr. Harris of Massachusetts, whose highly interesting and 

 useful treatise upon destructive insects, is a most valuable acquisition to the stores 

 of agricultural knowledge. 



The success with which science has developed the agencies concerned in the 

 various stages and processes of vegetation, and the certainty with which deficiences 

 of soil can now be detected and remedied, have suddenly elevated agriculture from 

 the condition of an art under the guidance of common observation and empirical ex- 

 periment, to a science regulated by recognised principles of induction. We are 

 indeed much mistaken if the day has not arrived when the successes of the book-farmer 

 shall cause his incredulous brother farmer of the old routine system, to cease his 

 taunts and spend some of his leisure hours in searching into books containing modern 

 information in regard to matters of husbandry. 



In preparing the work for the American farmer, the editor has had several objects 

 to fulfil. Of these, one of the principal was the reduction of the price, the cost of 

 the imported copy being so great as to prevent any extensive circulation of it in the 

 United States. Much of the irrelevant and less important materials in the original 

 have been omitted, their place being supplied by the addition of information con- 

 nected with the interests of American husbandry. In the selection of such informa- 

 tion, the editor has to acknowledge his great indebtedness to distinguished writers at 

 home and abroad, who have contributed, by elaborate works, separate treatises and 

 communications in periodicals, to promote the cause of agriculture. 



The American edition will contain a far greater number of plates and figures illus- 

 trating the various subjects ; notwithstanding which, its cost will be only about one- 

 fourth that of the imported work. 



