IV AUTHOR S PREFACE. 



delivered them, but the documents which would have formed the 

 basis of my teaching. 



The first part of this work treats in succession of the physical 

 and chemical phenomena of vegetation ; of the composition of vege- 

 tables and their immediate principles ; of fermentation ; and of soils. 

 The second comprises a summary of all that has yet been done on 

 the subject of manures, organic and mineral ; a discussion of the 

 subject of rotations ; general views of the maintenance and economy 

 of live-stock ; finally, some considerations on meteorology and cli- 

 mate, and on the relations between organized beings and the atmo- 

 sphere. 



I have endeavored, therefore, to give a summary view of all the 

 questions of rural economy that admit of scientific treatment. It 

 may be found, perhaps, that the number of these questions is still ex- 

 tremely small. Nevertheless, in regarding the multitude of inquiries 

 that have been instituted within a very few years only, in viewing 

 especially the ever-increasing interest attached to researches bear- 

 ing upon practical agriculture, we are bound to anticipate progress, 

 and to hope for conclusions important as regards science, profitable 

 to practice, and useful to humanity. 



