PREFACE 



THIS book is intended for the teacher who is more or less 

 in charge of the apparatus he uses. The necessity for ability 

 and skill in repairing or readjusting instruments of all kinds 

 is evident to any science teacher who has conducted a year's 

 experimental work ; and it is hoped that sufficient informa- 

 tion and instruction are contained in the following pages 

 to enable a teacher not only to acquire this necessary skill, 

 but to turn it to account in the making of simple laboratory 

 apparatus, and in the construction of new forms of apparatus 

 and teaching devices. 



The ability to " fix up " a piece of uncatalogued apparatus, 

 by which a point under discussion may be proved, is worth 

 the expenditure of time and trouble in its attainment, but 

 until now no systematic attempt has been made in this direc- 

 tion, and it is only through the organization of summer courses 

 for science teachers in Ireland and Yorkshire that the prospect 

 of success is held out. The present book has been written 

 upon the basis of experience obtained in the conduct of the 

 above summer courses, and though incomplete, and doubtless 

 full of imperfections, it should enable any searcher to obtain 

 sufficient assistance to be able thence to help himself. 



Many of the methods recommended here are not trade 

 methods. Some are superior, inasmuch as the question of 



