POPULAR LECTURES 



ON 



SCIENTIFIC SUBJECTS 





BY 



HERMANN VON HELMHOLTZ 



TRANSLATED BY 



E. ATKINSON, PH.D., F.C.S. 



FORMERLY PROFESSOR OF EXPERIMENTAL SCIENCE, STAFF COLLKOB 



FIRST SERIES 

 WITH AS INTRODUCTION by PROFESSOR TYNDALL 



LONDON 



LONGMANS, GREEN, AND CO. 



AND NEW YORK : 15 EAST 16 th STREET 



1895 



All rights reserved 



