IV PKEFAC& 



stand-point, and as no pretence is here made to impart 

 special chemical knowledge, it is hoped that Mr. Waring- 

 ton and the reader also will forgive any slight incursions 

 into a territory which the writer has no claim to enter 

 except upon sufferance. 



Structural botany, whether dealing with the outer con- 

 formation or the internal organization of plants, is only 

 incidentally treated of in these pages ; the classification 

 of plants is also passed over without notice, as not coming 

 within the scope of this Handbook. 



Detailed text-books of Botany, or of Vegetable Phy- 

 siology, expressly adapted to the requirements of agri- 

 culturists do not exist, but there are many works from 

 which a comprehensive general idea of the present state 

 of knowledge of these subjects may be obtained. 



In the compilation of the following pages the writer 

 has availed himself of Van Tieghem's " Traite de Botani- 

 que," the French translation of Sachs' " Physiologie 

 Vegetale" by Micheli, and Deherain's " Cours de Chimie 

 Agricole," etc. The works and memoirs of Darwin have, 

 of course, been laid under contribution, as well as nu- 

 merous scattered papers by various authors. More es- 

 pecially the writer has to acknowledge his obligations to 

 the voluminous records of the noble series of cultural 

 experiments carried out at Eothamsted for so many years 

 by Sir J. B. Lawes and Dr. Gilbert. The " Memorandum 

 Sheet " published by these experimenters supplies annu- 

 ally a condensed summary of the results of their experi- 

 ments, and is a document that should be carefully 

 studied with due reference to its professed object, by all 

 who have the advancement of agricultural knowledge at 

 heart. M. T. M. 



