VI PREFACE. 



induced some zealous and active citizens of Lowell, to 

 ask me to deliver a course of lectures on agricultural 

 chemistry. Mj reading on that subject had been very 

 limited; yet, willing to contribute my mite to so 

 good a cause, and to embody my own notions on this 

 subject, notes for the lectures were prepared week by 

 week as they were delivered; and urged to their pub- 

 lication, the notes were thrown into chapters and sec- 

 tions, and so the book appeared at last, divested of 

 the colloquial style befitting the lecture room, and so 

 much condensed as to be scarcely recognizable as lec- 

 tures. The work was favorably received at home 

 and abroad, where a considerable portion was re- 

 printed. It has passed through several editions, each 

 being enlarged by the addition of new matter, to keep 

 pace with the times. To the present edition is added 

 an entire new chapter on bones, and superphosphates 

 of lime and alkalies. Should another edition be called 

 for, I trust it will be then and there shown in a new 

 chapter on the analysis of the mineral part of soil, 

 that, agriculture in demanding of chemistry any real 

 practical result from such analyses of soils beyond 

 this, their great uniformity of composition, is asking 



