vl TRANSLATORS PREFACE. 



ticulars, which disclose to us much of the in 

 terior spirit of the Academy of Sciences, not 

 always of a kind the most creditable to some 

 of Arago s former contemporaries. 



But a far higher interest will be found to 

 belong to those eloquent memoirs, or eloges of 

 eminent departed men of science, who had at 

 tained the distinction of being members of the 

 Academy. 



In these the reader will find a luminous, 

 eminently simple, and popular account of the 

 discoveries of each of those distinguished indi 

 viduals, of a kind constituting in fact a brief 

 history of the particular branch of science to 

 which he was devoted. And in the selection 

 included in the present volume, which consti 

 tutes but a portion of the entire series, we have 

 comprised the accounts of men of such varied 

 pursuits as to convey no inadequate impression 

 of the progress of discovery throughout a con 

 siderable range of the whole field of the physi 

 cal sciences within the last half century. 



The account given by the author, of the prin 

 cipal discoveries made by the illustrious subjects 

 of his memoirs, is in general very luminous, 

 but at the same time presupposes a familiarity 

 with some parts of science which may not 

 really be possessed by all readers. For the 



