10 PREFACE. 



scruple, since the novelty of my work was intended to con- 

 sist, not in its superiority 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 lii>i<»rians, and studied the original au- 

 thors. According to the plan which I have pursued, the his- 

 tory of each science forms a whole in itself, divided into dis- 

 tinct hut 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 impossible not 

 to see that such an undertaking is, in no small degree, ardu- 

 ous, and its event obscure. But all who venture upon such 

 tasks must gather trust and encouragement from reflections 

 like those by which their great forerunner prepared himself 

 for his endeavors ; — by recollecting that they are aiming to 

 advance the best interests and privileges of man ; and that 

 they may expect all the best and wisest of men to join them 

 in their aspirations and to aid them in their labors. 



" ' Concerning ourselves we speak not ; but as touching 

 the matter which we have in hand, this we ask; — that men 

 deem it not to be the setting up of an Opinion, but the per- 

 forming of a Work : and that they receive this as a certain- 

 ty — that we are not laying the foundations of any sect or 

 doctrine, but of the profit and dignity of mankind: — Fur- 



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

 Physik, Gmelin's Geschichte der Chemie, Thomson's History of Chemistry, Spren- 

 gel"s History of Medicine, his History of Botany, and in all branches of Natural 

 History and Physiology, Cuvicr's works: in their historical, as in all other portions, 

 most admirable and instructive. 



