8 AUTHOR'S PREFACE 



set required for twelve students, given in the Appendix, can 

 be purchased for about £d,o. Neither need the fitting of a 

 laboratory for experimental work be a costly undertaking. 

 A demonstration table, provided with drawers and a sink, 

 working benches for twelve students, provided with a rack 

 for reagents, fume cupboard, apparatus cupboard, shelves 

 for chemicals, blackboard, balance shelf, and distillation table, 

 also provided with a sink, together with gas and water supplies, 

 constitute the equipment necessary, and cost from ;^5o up- 

 wards, according to the style of work. It is very desirable 

 that for experimental work of this character the working 

 benches should be so placed that the students face the 

 demonstration table. 



The course is divided into thirty-six experimental studies, 

 through each of which the student, under the supervision of 

 the teacher, is expected to work. Each student should work 

 independently, and only in exceptional cases should two 

 students be allowed to work together for a particular experi- 

 ment. Each day's work should be accompanied by a revision 

 class. Revision is quite as essential as the experimental work ; 

 for it is by this means that the teaching of each experiment 

 is brought home to the student. It is desirable, and in the 

 absence of revision necessary, that the student should answer 

 in writing the questions and problems set. A written and 

 practical examination should follow the conclusion of each 

 part of the course. The sections on special subjects the 

 teachers are recommended to expand into lectures to the 

 class ; it is not intended that the students should themselves 

 make the experiments described in these sections. 



The value of this course as a means of training will, to 

 a large extent, depend upon the care, thoroughness, and 

 accuracy with which the experimental work is carried out. 

 In such work it is especially necessary to remember that 

 whatever is worth doing at all is worth doing well. 



My thanks are due to Mr. F. Hughes, who has kindly made 

 the drawings for the figures which illustrate this volume. 



T. S. D. 



