EDITOR'S PREFACE. 



THE former edition of this work was prepared in the form of a report on the 

 present state of Organic Chemistry. The state of a science such as this could not 

 be exhibited by a systematic treatise on organic compounds, but by showing that 

 the science was so far advanced as to be useful in its practical applications. 



The work was written by a Chemist, and addressed to Chemists. The author 

 did not flatter himself that his opinions would be so eagerly embraced by agricul- 

 turists, as circumstances have shown to be the case. Hence his language and style 

 were less adapted for them than for those who are conversant with the abstract 

 details of chemical science. But the eager reception of the work by agriculturists 

 has shown that they possess an ardent desire to profit by the aids offered to them 

 V>y Chemistry. It, therefore, became necessary to adapt the work for those who 

 have not had an opportunity of making that science a peculiar object of study. 



The Editor has endeavoured to effect this change. In doing so, it was necessary 

 to retain the original character of the work ; hence those alterations omy have 

 been made which are calculated to render the work more generally useful. It 

 must be remembered that the object of the author was not to write a " System of 

 Agricultural Chemistry," but to furnisn a " Treatise on the Chemistry of Agricul- 

 ture." It is to be hoped that those who are acquainted with the general doctrines 

 of Chemistry will find no difficulty in comprehending any of the principles here 

 developed. 



The author has enriched the present edition with many valuable additions; 

 allusion may be particularly made to the practical illustration of his principles 

 furnished in the Supplementary Chapter on Soils. The analyses of soils contained 

 in that chapter will serve to point out the culpable negligence exhibited in the 

 examination of English soils. Even in the analyses of professional chemists, 

 published in detail, and with every affectation of accuracy, the estimation of the 

 most important ingredients is neglected. How rarely do we find phosphoric acid 

 among the products of their analyses? potash and soda would appear to be 

 absent from all soils in the British territories ! Yet these are invariable constituents 

 of fertile soils, and are conditions indispensable to their fertility. 



Primrose, November 22, 1852. 



