viii PEEFACE 



gations often tend to be less accounts of the experiment as a 

 whole than discussions of such of its results as bear upon 

 the dominant idea with which Lawes and Gilbert were then 

 engrossed. 



The outsider, again, who has any knowledge of his subject 

 cannot fail to bring some ideas of his own which he can find 

 illustrated and elucidated in the work done at Eothamsted. 

 For here comes the jDarticular distinction of the Eothamsted 

 Experiments ; the plots exist to-day as they have been for the 

 last fifty years or so, and records of the most astonishing 

 completeness remain of their past history, so that as soon as 

 one looks closely into the material there is hardly any j^art of 

 the science of the nutrition of the plant on which it cannot 

 be made to throw light Indeed only a portion of the story 

 of the Eothamsted Experiments has yet been told, for new 

 matter will be discovered in them as our knowledge grows 

 and fresh lines of investigation are opened up. Accordingly, 

 in planning this account I have tried to look at each experiment 

 from as general a point of view as possible, and to set out 

 what information it can afford both to the student of agri- 

 cultural science and to the man more occupied with practical 

 problems. I have endeavoured to summarise under the head 

 of each crop the mass of information that has already been 

 published in the long series of Rothamsted Memoirs, and to 

 add other facts and deductions arising out of the experiments 

 which the original investigators had not hitherto been able to 

 publish. 



As to the purpose of the book, that is best dealt with by 

 discussing the purpose of the Eothamsted Experiments them- 

 selves. They are, above all, attempts to obtain knowledge — 

 to ascertain the conditions under which the plant grows and 

 the soil supplies it with nutriment And as the attainment of 

 knowledge is the prime object, practical considerations are put 

 on one side in framing the scheme of the experiments. For 

 example, on one of the Eothamsted fields wheat has been grown 

 for the last sixty years, year after year, on the same plots of 



