OBJECTS ILLUSTRATING SCIENCE. 81 



far back into the History of Science, how many instruments 

 have disappeared ? After having been kept for some generations in 

 families, with the respect they deserve, they are often passed over un- 

 noticed and are lost for science, because they, in a very short time, cease 

 to present any definite interest. If preserved in the laboratory of the 

 philosopher, they are often disfigured for other reasons ; professors, 

 vho have them at their disposal, are often carried away by the love of 

 science, and cannot always resist altering an ancient instrument, in 

 order to adapt it to the purposes of some experiment at that moment 

 under consideration When once the modifications have been made, 

 the instrument is never brought back again to its former construction, 

 and often the new arrangement does not entirely answer the purposes 

 of the fresh researches. And many a time has the very author of the 

 first discovery mutilated his own instrument in order to follow up the 

 investigation of some matter of secondary importance, and the original 

 apparatus is for ever lost. 



These observations are suggested by the difficulties which we have 

 met with in collecting, as far as we could have wished, all the historical 

 instruments connected with French discoveries in science, and if we 

 have succeeded in bringing a certain number together at this exhibition 

 it is owing to the readiness shown by the directors of our scientific 

 establishments in responding to the call made by England. 



To speak here only of the apparatus included in the Physical 

 Section, the " Ecole polytechnique," the " Observatoire,'' the " College 

 de France," the " Faculte des Sciences," have united with the 

 " Conservatoire des Arts et Metiers " in order to call to mind, by a 

 few original instruments, the discoveries of most of the celebrated 

 French scientific men. This last institution, founded at the beginning 

 ol this century, and endowed with all the valuable objects found after 

 the great political events of the preceding years, has been able to save 

 from destruction many instruments interesting on more than one 

 account. Those of the i8th century, however, are few in number ; 

 and we can mention but one or two that date as far back as the I7th 

 century. 



The immortal Pascal, whom we might place by the side of 

 Torricelii, is only represented by his calculating machine ; and if it 

 affords but slight scientific interest it is, at least, undoubtedly 



G 



