viii GENERAL PREFACE 



tion on the part of the teacher of the aims, the principles of 

 organization, and the methods of instruction ; it is to meet these 

 needs that this series is being issued. The books attempt to 

 present such generalizations of science as the average pupil 

 should carry away from his school experience and to organize 

 them for the preparation of the teacher and for presentation to 

 the class. The volumes will therefore be of three kinds: 

 (i) source books with accompanying field and laboratory guides 

 for the use of students in normal schools and schools of educa- 

 tion, and of teachers, (2) pupils' texts and notebooks, and 

 (3) books on the teaching of the various science subjects. In 

 the first the material will be organized with special reference 

 to the training of the teacher and the most effective methods 

 of presenting the subject to students. In the second the matter 

 will be simplified, graded, and arranged in such a way that 

 the books will serve as guides in science work for the pupils 

 themselves. Moreover, they will furnish texts for the grades 

 and high school that will simplify the teacher's task of presenta- 

 tion and will assure well-tried and well-organized experiences, 

 on the part of the pupil, with natural objects. This series of 

 texts for elementary and secondary schools will have dependent 

 continuity and the subject-matter will gradually increase in 

 difficulty to accord with the increasing capacity of the pupils. 

 It will furnish a unified course in science. The third type of 

 book is for the teacher and deals with the history, aims, prin- 

 ciples of organization, and methods of instruction in the several 

 sciences. 



