vi PREFACE 



Possessed as yet of no methods for these were first created by their labors 

 and are only rendered comprehensible to us by their performances they 

 grapple with and subjugate the object of their inquiry and imprint upon it 

 the forms of conceptual thought. Those who know the entire course of the 

 development of science will . . . judge more freely and more correctly the sig- 

 nificance of any present scientific movement than those who, limited in their 

 views to the age in which their own lives have been spent, contemplate merely 

 the trend of intellectual events at the present moment. 



At a time when the forces of science are being diverted from the 

 promotion and conservation of civilization to its destruction, and 

 when attempts are being made to turn the waters now flowing 

 in the stream of science back into ancient and so-called classical 

 channels, it will be well for the general reader no less than the 

 student of science to review its history, and to judge for himself 

 concerning its proper place in contemporary life and education. 

 Many volumes would be required to depict the lives of the workers, 

 often marked by self-denial and sometimes by persecution, 

 to trace the full significance of their achievements, or to portray 

 the spirit animating their labors ; that spirit of science to which, 

 regarding it as a critic rather than a votary, impressive tribute 

 has been paid by one of our modern seers : 



A greater gain to the world . . . than all the growth of scientific knowl- 

 edge is the growth of the scientific spirit, with its courage and serenity, its 

 disciplined conscience, its intellectual morality, its habitual response to any 

 disclosure of the truth. 



F. G. Peabody. 



It has naturally been foreign to the purpose of the authors to 

 admit matter too technical for the general student or, on the other 

 hand, too slight in its influence on the general progress of science. 

 The division of responsibility between them corresponds roughly 

 to that implied by the title "mathematical" and "natural 

 sciences", and emphasis has been laid on interrelations rather 

 than on distinctions between the various sciences. The mathe- 

 matical group from their relatively greater age and higher de- 

 velopment afford the best examples of maturity; the natural 

 sciences illustrate more clearly recent progress. No attempt 



