vi PREFACE 



without tliis preliminary chemical knowlerlf^e, and it is for 

 such that this Vook is mainly intended. ' "^ ' .' , . T 



Since the work is written for the agriculturist rather than 

 for the chemist, few references to chemical literature are 

 given. 



The book, was prepared while the author was in to ch with 

 many of the crops and agricultural practices of South Africa, 

 and it was thought advisable to give some account of the 

 products of tropical and sub tropical agriculture in addition to ; 

 the matters relating to ordinary English farming. 



In these days of. frequent travel , and emigiution, such 

 inclusions may be of service to many agricultural students 

 who, in the future, may becr.me Colonists, while it may render 

 the book more suited to the needs of the Colonial rea:der, aid 

 to all a comparison of tropical with temperate conditions 

 cannot fail to be useful. 



Every writer is apt to give undue prominence to the 

 particular subjects upon which he has himself woiked, and 

 perhaps some examples of this weakness: may be found iri the 

 present volume. 



The importance of the composition as well as the amount of 

 the ash constituents of the food of animals, to which leference 

 is made in chap, ix., though perhaps not strongly felt in 

 Europe where diet is vaiied, is considerable in such countries 

 as South Africa, where the usual food of draught animals is 

 composed almost entirely of cereals. 



In chap. iii. a brief account is given of the main causes of 

 tiie motion of water in a Foil, intended to clear away the 

 confusion which is apt to attend the usual "explanation" as 

 to its being due to "capillarity." 



Chap. X. deals with the variations in the composition of 

 cows' milk in greater detail, perhaps, than the elementary 

 character of the book justifies ; but here again the popular 

 interest at present shown in the subject must be the excuse. 



There are, doubtless, other respects in which the work is 

 ''out of balance," but for these the reader's indulgence is 

 solicited. 



The author hopes that, in spite of this, the book may prove 

 of service to those for w^hom it is intended. . 



October 1908. 



