INTRODUCTION. 7 



that it is on the average far inferior to the collective system 

 here advocated (in which all students of a class work together 

 on the same topics, each trying for himself the full set of ex- 

 periments), which I have now tried for five years. Of course 

 it is only the use of simple home-made apparatus which allows 

 this plan at all, for no laboratory could afford enough of the 

 exact apparatus to supply every student with all pieces ; but, 

 happily, as already stated, the simpler apparatus is for 

 beginners educationally equal to the more elaborate, if not 

 superior to it. Of course the spirit of this system must be 

 observed rather than the letter, and there are times when 

 practical considerations make it profitable to have students 

 work together in pairs (or larger groups), or when some par- 

 ticular experiment may best be prepared by one for the use of 

 all. The objections to the individual or special-problem 

 method are, that to keep in touch with so many lines of work 

 at once entails great and needless labor upon the teacher ; that 

 students are found to derive comparatively little good from the 

 observation of experiments not tried by themselves ; that the 

 members of the class cannot compare results and profit by the 

 discussion thereby suggested ; that the}' cannot derive full 

 advantage from lectures or other theoretical instruction when 

 this is dissociated from the subjects they are studying, as must 

 usually be the case for most of the students on this plan; and, 

 finally, that as no student can cover all the topics, his training 

 and knowledge at the end of the year are badly proportioned, 

 his more thorough knowledge of some things not compensating 

 for his ignorance of others. On the other hand, the collective 

 system, keeping the students all working together on the same 

 problems, permits more profitable use of the teacher's energy; 

 allows all students to do all of the work; lets them profit by 

 comparison and discussion of one another's results; enables 

 them to understand lectures which can be fitted exactlv to their 



j 



stage of progress ; and gives them at the end of the year a 

 Avell-proportioned knowledge of the entire subject. This is the 

 principle of the method universally adopted in other student 



