PREFACE xi 



Throughont I liave kept the teacher in view, and have 

 endeavoured to supply him with tlie sunmiarjes and iUus- 

 trations wliich will be useful in his elass wi)i"k. 



Of course, in many respects the book covers tlie same 

 ground as the summary of the Kothamsted Experiments <lrawn 

 up by Gilbert for his lectures in America, whieh weri' published 

 both by the United States Department of Agriculture and liy 

 the Highland and Agricultural Society of Scotland in ISO."). 

 The American lectures were, however, in the main intended 

 for the reader who was already eipiipped with a considerabk" 

 knowledge of agricultural science; on the one hand, they did 

 not deal with all the Rothamsted work, and on the other, they 

 went into much greater detail than is here attempted. In the 

 present book I have endeavoured to make matters })lain to 

 the non-technical reader and to elucidate the subject by 

 diagrams and simplified tables, leaving the specialist to ccjnsult 

 the original papers for fuller information. 



By the kind permission of ]Mr R. Warington and the 

 Council of the Royal Society, I have been permitted to reprint 

 Mr \yarington's account of Law^es and Gilbert from the Ol)ituary 

 Notices of the Royal Society, and this forms the best intro- 

 duction to the history of the Rothamsted Experiments and the 

 personality of their founders. 



In the Appendix will be found a bil)liograi)liy of all the 

 more important papers issued by Lawes and Gilbert, together 

 with others which deal with Rothamsted material by inde- 

 pendent investigators. A list will also be found of previous 

 books which have given a general account of the experiments, 

 including Dr Fream's little book published in 1888, which, 

 though dealing only with wdieat, barley, and grass, has formed 

 for so many readers their introduction and guide to the 

 Rothamsted investigations. 



A hst is given of the men who have worked in the Koihani- 

 sted Laboratory, either as members of the stall", or as voluntary 

 workers for a long or short period. Although by the terni> 

 of the trust deed no teaching may be done at the Station, 



