xxn PREFACE TO THE 



largely from other writers, both of the histories of 

 special sciences and of philosophy in general*. I 

 have done this without scruple, since the novelty of 

 my work was intended to consist, not in its supe- 

 riority as a collection of facts, but in the point of 

 view in which the facts were placed I have, how- 

 ever, in all cases, given references to my authorities, 

 and there are very few instances in which I have 

 not verified the references of previous historians, and 

 studied the original authors. According to the plan 

 which I have pursued, the history of each science 

 forms a whole in itself, divided into distinct but 

 connected members, by the Epochs of its successive 

 advances. If I have satisfied the competent judges 

 in each science by my selection of such epochs, the 

 scheme of the work must be of permanent value, 

 however imperfect may be the execution of any of its 

 portions. 



With all these grounds of hope, it is still impos- 

 sible not to see that such an undertaking is, in no 

 small degree, arduous, and its event obscure. But 

 all who venture upon such tasks must gather trust 



1 Among these, I may mention as works to which I have peculiar 

 obligations, Tennemann's Geschiohte der Philosophic, Degerando's 

 Histoire Comparee des Systemes de Philosophic, Montucla's Histoire 

 des Mathematiques, with Delalande's continuation of it, Delambre's 

 Astronomic Ancienne, Astronomic du Moyen Age, Astronomic 

 Moderne, and Astronomic du Dixhuitieme Siecle ; Bailly's Histoire 

 d' Astronomic Ancienne, and Histoire d'Astronomie Moderne, Voiron's 

 Histoire d'Astronomie (published as a continuation of Bailly), Fischer s 

 Geschichte der Physik, Gmelin's Geschichte der Chemie, Thomson's 

 History of Chemistry, Sprengel's History of Medicine, his History of 

 Botany, and in all branches of Natural History and Physiology, 

 Cuvier's works, in their historical, as in all other portions, most 

 admirable and instructive. 



