PREFACE FOR THE LABORATORY MANUAL 



Laboratory work is an essential part of any course in 

 science. The mental development acquired by pupils 

 performing a series of experiments, interpreting their 

 results, and carefully recording them, is of equal, if not 

 more value, than the mere accumulation of facts. We 

 cannot justify the existence of any course in the high 

 school which has the acquiring of information as its only 

 purpose. The performance of experiments is not a 

 mechanical part of the course in which the use of the 

 intelligence of the pupil plays no part. Too much em- 

 phasis can not be placed upon the fact that the pupil 

 must perform experiments intelligently, using his head as 

 well as his hands. Frequently beginners are inclined to 

 think that laboratory work is merely entertaining. 



The following outlines for experiments are the result 

 of about fifteen years of experiment and search for inter- 

 esting and fundamental scientific matter adapted to the 

 age and preparation of pupils entering the high school. 

 During this period of experimentation from six to nine- 

 teen classes a year have pursued this course. It has thus 

 been tried on thousands of students under the direction 

 of many teachers. We gratefully acknowledge our indebt- 

 edness to these teachers for their many valuable sugges- 

 tions and criticisms. 



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