xii CONTENTS 



PAGE 



'On the actual Foundations of Geometry/ (Lecture, 



Heidelberg, Gottingen Nachrichten, 1868) .... 254 



' On the Origin and Significance of Geometric Axioms/ 

 Lecture at Heidelberg, translated in Pop. Scient. Lect., 

 Series II 254 



Note on the Fundamental Notions of Mathematics and 

 Physics 256 



1869. Correspondence with Beltrami 263 



'The Facts of Perception/ Address delivered in 1878 



at the Commemoration of the Foundation of the University 



of Berlin 267 



'On the Origin and Signification of Geometrical Pro- 

 positions/ Reply to Prof. Land, 1878. 



' On the Physiological Action of brief Electrical Shocks 

 in the Interior of extended conducting Masses/ (Heidel- 

 berg Scientific and Medical Society) . . . . 268 

 ' On Electrical Oscillations/ (Heidelberg Society) . 268 

 'On the Aim and the Developments of the Natural 

 Sciences/ (Innsbruck Naturforscher-Versammlung) . 268 

 ' On Hay^ever/ Vir chow's Archiv .... 268 

 'On Sound Vibrations in the Cochlea/ (Heidelberg 

 Society) 269 



1870. 'On the Laws of Inconstant Electrical Currents in 

 Material Conductors/ (Heidelberg Society) . . . 269 



'On the Theory of Electrodynamics/ Part I : 'On the 

 Motional Equations of Electricity for resting conducting 

 Bodies/ Crelle Journ., LXXI I 269 



Call to the Professorship of Physics in Berlin . . 275 



1871. ' On the Origin of the JPlanetary System/ (Lecture, 

 Heidelberg.) Translated in Pop. Set. Lect., Series II . 280 



PROFESSOR OF PHYSICS IN BERLIN, 1871-1888 . . . 281 



1871. 'On the Rate of Transmission of Electrodynamic 

 Effects/ (Berlin Academy) 282 



'In memory of Gustav Magnus/ (Address to the 

 Academy of Sciences, Berlin, translated in Pop. Sci. Lect., 

 Series II) 282 



' Preface and Critical Supplement to the German trans- 

 lation of " J. Tyndall, Fragments of Science," ' 1874 . . 284 



Journey to England 285 



1872. 'On the Theory of Electrodynamics/ (Berlin Academy) 288 



