To the Teacher xi 



The chapters and sections in this book are not of even 

 length. In order to preserve the unity of subject matter, 

 it was felt desirable to divide the book according to sub- 

 jects rather than according to daily lessons. The vary- 

 ing lengths of recitation periods in different schools, and 

 the adaptation of the course to individual instruction as 

 well as to class work, also made a division into lessons 

 impracticable. Each teacher will soon discover about 

 how much matter her class, if she uses the class method, 

 can take each day. Probably the average section will 

 require about 2 days to cover ; the longest sections, 5 days. 

 The entire course should easily be covered in one year 

 with recitations of about 25 minutes daily. Two 5o-min- 

 ute periods a week give a better division of time and also 

 ought to finish the course in a year. Under the individ- 

 ual system, the slowest diligent children finish in 7 or 8 

 school months, working 4 half-hours weekly. The fastest 

 do it in about one third that time. 



Upon receipt of 20 cents, the publishers will send a 

 manual prepared by the author, containing full in- 

 structions as to the organization and equipment of the 

 laboratory or demonstration desk, complete lists of ap- 

 paratus and material needed, and directions for the con- 

 struction of a chemical laboratory. 



The latter is a laboratory course in which the children are turned loose 

 among all sorts of interesting materials and apparatus, kaleidoscope, 

 microscope, electric bell, toy motor, chemicals that effervesce or change 

 color when put together, soft glass tubing to mold and blow, etc. The 

 teacher demonstrates various experiments from time to time to show the 

 children what can be done with these things, but the children are left 

 free to investigate to their heart's content. There is no teaching in this 

 introductory course other than brief answers to questions. The astron- 

 omy and geology reading usually accompany the work in introductory 

 science. 



