INDEX 



ACCOMMODATION, mechanism of, 7, 



92, 94- 



Action, at a distance, 203. 

 Action, definition of dynamical, 245. 

 Action, principle of least, 235, 240, 243. 

 /Esthetics, Helmhokz on, 268. 

 Aguilonius, reference to, 180. 

 After images, 177. 

 Air, micro-organisms in, 29. 

 Airy, reference to, 91, 118. 

 Ampere, 210. 



Andrews, Thomas, reference to, 91. 

 Apparatus, electrical, for physiology, 



36. 



Arm, muscles of, Helmholtz on, 170. 

 Art, ethical importance of, 270 ; nature 



of, 269. 

 Axioms of geometry, Kant's opinions 



as to, 258. 



BABBAGE, Charles, use of silvered 



mirror by, 77. 

 Bach, reference to, 167. 

 Bacon, on heat, 46. 

 Baconian philosophy in Germany, 12. 

 Baden, government of, 184. 

 Baden, Grand Duke of, reference to, 



280. 

 Balloons, steering of, and theory of, 



203. 



Beats, nature of, 156, 158. 

 Beethoven, reference to, 134. 

 Behr, reference to, 77. 

 Bell, John and Charles, reference to, 



152. 



Beltrami, reference to, 266. 

 Bentley, reference to, 203. 

 Berlin, Physical Society of, 24. 

 Berlin, University of, 183, 239. 

 Bernard, Claude, reference to, 14. 

 Bernoulli, Daniel, reference to, 40. 

 Bertrand, reference to, 195. 

 Bessel, reference to, 70, 202. 

 Bezold W. von, reference to, 218. 

 Bibliography, 291. 

 Binz, reference to, 182. 

 Bismarck, head of, 283. 

 Bones of the ear, 133, 135. 



I Bonn, Helmholtz on, 88. 

 i Bonn, University of, 129. 

 ' Bowman, physiologist, reference to, 14. 



Boyle, Robert, reference to, 116. 



Branco, Professor, reference to, 58. 



Brewster, Sir David, reference to, 91, 

 112, 118, 119. 



British Association, Edinburgh meet- 

 ing 1892, 282. 



British Association meeting at Hull 

 1854, 91. 



Brucke, early friendship with Helm- 

 holtz, 10, 11, 13, 24, 25, 74, 77, in. 



Brucke, on ciliary muscle, 101. 



Butterfly, life of a, considered em- 

 pirically, 257. 



CAGNIARD DE LA TOUR, reference to, 



26. 



Cape d'Antibes, 192. 

 Carnot, Sadi, reference to, 50, 194. 

 Carpenter, reference to, 14. 

 Cayley, Arthur, reference to, 190. 

 Chicago, International Exhibition at, 



282. 



Chladni, plates of, 20. 

 Ciliary muscle, 101, 102. 

 Clang tint, 143. 

 Clapeyron, on heat, 50. 

 Clausms, physicist, 10, 23, 43, 194, 205. 

 Clouds, Helmholtz on, 223. 

 Coccius, ophthalmoscope of, 77. 

 Cochlea, action of, 140, 141, 152. 

 Coil, induction, of Du BoisReymond, 36 

 Colding, on energy, 50. 

 Colour blindness, 125. 

 Colour, Helmholtz's researches on, 112. 

 Colour, nature of, 116. 

 Combination tones, 159, 161. 

 Conservation of energy, 193, 242. 



Cooper, Dr, reference to, 91. 

 Copernicus, reference to, 19. 

 Corresponding retinal points, 173, 178. 

 Corti, physiological action of the organ 



of, 151, 154. 

 Coulomb, reference to, 21 ; law of 



electrical attraction, 204. 



295 



