vi TRANSLATORS’ PREFAOR. 
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 éloges 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- 
eal 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 
