viii GENERAL PREFACE 



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 gen- 

 eralizations of science as the average pupil should carry away 

 from his school experience and to organize them for the prepara- 

 tion of the teacher and for presentation to the class. The volumes 

 are therefore of three kinds: (i) source books with accompanying 

 field and laboratory guides for the use of teachers and students in 

 normal schools and schools of education; (2) pupils' texts and 

 notebooks; and (3) books on the teaching of the various science 

 subjects. In the first the material is organized with special refer- 

 ence to the training of the teacher and the most effective methods 

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

 simplified, graded, and arranged in such a way that the books will 

 serve as guides in science work for the pupils themselves. More- 

 over, they will furnish texts for the grades and high school that 

 will simplify the teacher's task of presentation and will assure to 

 the pupil well-tried and well-organized experiences with natural 

 objects. This series of texts for elementary and secondary schools 

 will have dependent continuity and the subject matter will gradu- 

 ally 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^ 

 principles of organization, and methods of instruction in the 

 several sciences. 



