VI PREFACE. 



the general relations of geology to agriculture ; — Part III., to 

 the various methods, mechanical and chemical, by which 

 the soil may be improved, and especially to the nature of 

 manures^ by which soils are made more productive, and the 

 amount of vegetable produce increased; — and Part IV., to 

 the results of vegetation^ to the kind and value of the food 

 produced under different circumstances, and its relation to 

 the growth and feeding of cattle, and to the amount and 

 quality of dairy produce. 



By this method I have endeavoured to ascend from the 

 easy to the apparently difficult ; and I trust that the willing 

 and attentive reader will find no difficulty in keeping by my 

 side during the entire ascent. 



The Author has much pleasure in now presenting these 

 Lectures to the public in a complete form. He has only to 

 express a hope that the delay which has occurred in the pub- 

 lication of the latter part of the work has enabled him to ren- 

 der it more useful, and therefore more worthy of the public 

 approbation. 



Note. — The rapid sale of a large impression having rendered a second 

 edition of the first and second Parts necessary before the entire comple- 

 tion of the work, such alterations, corrections, and additions only have 

 been made as could be introduced without altering the original paging of 

 the work. Several oversights, however, have been corrected, and some 

 omissions supplied, which presented themselves in the earlier edition. 



