

DEDICATED TO 



SIR CHARLES LAWES-WITTEWRONGE, Baronet 



OF ROTHAMSTED 



WHO HAS SHOWN IN OTHER FIELDS 



THE DISTINCTION AND IMAGINATION 



WHICH MARKED HIS FATHER'S WORK 



FOR AGRICULTURE 



First Edition ...... June 1909 



Reprinted . , • . . June 1910 



Reprinted ...... May 1912 



