vi Preface 



in Part II. Special attention has been paid to those 

 portions of the subject which experience has shown are 

 usually imperfectly grasped perhaps on account of the 

 difficulty of providing the student with ready examples 

 of domestic application and the theoretical side of the 

 subject, e.g. the ideas o "energy" and of "molecular 

 action", is treated more fully than is usual in works of 

 similar character. 



Parts I and II will provide sufficient material for 

 a course of at least two years for pupils in secondary 

 schools, and will be found to cover the requirements of 

 many examinations, such as the Oxford Senior Local 

 and those held under the auspices of the Board of 

 Education at the various Domestic Training Centres. 



The author's thanks are due to Messrs J. and A. 

 Churchill for permission to reproduce Figs. 20, 27, 79, 

 and 95, and to Messrs Macmillan and Co. for Figs. 21 

 and 87. For many valuable criticisms and useful 

 suggestions, received from the General Editor of the 

 series while the book was in the press, the writer 

 tenders his grateful thanks. 



CHARLES W. HALE. 



CHELSEA, 



March, 1915. 



NOTE. The London County Council accepts no responsibility 

 for the author's opinions and conclusions. 



