vi PREFACE 



author believes it advantageous early in the course to make 

 some use of the theories of high school science in order to 

 give scientific unity to explanations of various common 

 phenomena. Care has been exercised to distinguish sharply 

 at all times between fact and theory, and to make clear the 

 restrictions that must accompany the use of theories whether 

 in school or elsewhere. 



Enough of a knowledge of the differentiated high school 

 sciences should be gained in a general science course to serve 

 as a real introduction to them. This will enable pupils 

 later to make an intelligent choice of which of these sciences 

 they care to pursue. 



However skillfully information for beginners in science 

 may be selected and presented, it will fail very largely of its 

 purposes as " knowledge-making material" if no need for it 

 has arisen in the minds of pupils, and if no apparent use for 

 it exists. Where a desire for knowledge is based on needs 

 that have been experienced, it calls forth effort in the school- 

 room even as it does in the larger field of life experiences. 

 A purpose of the text is to arouse and in some large measure 

 to guide the desires of pupils for a scientific understanding of 

 life's problems, and to furnish some of the material and con- 

 ditions necessary to secure these ends. 



Perhaps foremost of all the ends sought in the teachings 

 of General Science is an habitual scientific attitude of the 

 pupils the state of mind that demands the facts in all 

 cases; that discriminates in the relative importance and 

 pertinence of facts; that can so associate them as to get their 

 chief significance whether in specific relationships or in gen- 

 eral applications; that does not rest satisfied with "glittering 

 generalities" but tests them out to ascertain if theory fits 

 facts when applied to known conditions and existing situa- 

 tions. In other words, the facts of the discussions in General 

 Science, valuable as they may be in themselves, are to be 



