viii. 



PREFACE. 



the sciences and Arts. So vast are the subjects, that a writer 

 attempting to include the whole, would find that a library, not a 

 volume, would be the result of his labors. Besides, with the 

 excellent elementary works already mentioned, and Prof. Gray s 

 Botanical Text-book, repetition could not have been avoided, and 

 this too, has been most scrupulously abstained from, as regards 

 works in general circulation among us. So again, the topics 

 treated upon in the early chapters are presented merely in out- 

 lino. Agricultural Meteorology though essentially a most inte 

 resting and important application of Science, is yet in its ear 

 liest infancy ; and the materials do not exist for accurate or ex 

 tended instruction ; while the Natural History of Plants, the Air, 

 Water, &c., belong rather to the department of the Chemist and 

 the Vegetable Physiologist, than to the practical Agriculturist. 

 Enough only is written on these subjects to serve as an intro 

 duction to what follows. 



In many instances, and always in the Analyses, the authority 

 quoted is mentioned, chiefly in order that the Teacher may be 

 able to refer directly to the original, where he will usually meet 

 with a more complete elucidation of the subject than could be 

 admitted into these pages. 



It will be observed that the work is printed in type of three 

 sizes. Those portions which are considered as peculiarly im 

 portant, or as being capable of comprehension by students of all 

 ages, are printed in the largest type ; that which is abstruse is 

 in a second sized ; and that which peculiarly interests the prac 

 tical farmer is in the smallest type. The Chapters are likewise 

 BO arranged as to permit the teacher to select such subjects as he 

 chooses. 



