CONTENTS xiii 



XXVI Michael Faraday (1791-18 67) 190 



ON FLUID CHLORINE 

 ELECTRICITY FROM MAGNETISM 



XXVII Joseph Henry (1797-1878) 198 



ON THE PRODUCTION OF CURRENTS AND SPARKS 

 OF ELECTRICITY FROM MAGNETISM 



XXVIII Sir Charles Lyell (1797-1875) 206 



UNIFORMITY IN THE SERIES OF PAST CHANGES 

 IN THE ANIMATE AND INANIMATE WORLD 



XXIX Charles Darwin (1809-1882) 226 



NATURAL SELECTION 



XXX Theodor Schwann (1810-1882) 245 



CELL THEORY 



XXXI Hermann von Helmholtz (1821- 



1894) 273 



THE CONSERVATION OF ENERGY 



XXXII Louis Pasteur (1822-1895) 304 



INOCULATION FOR HYDROPHOBIA 



XXXIII James Clerk Maxwell (1831- 



1879) 320 



THE MAXWELL AND HERZ THEORY OF ELECTRIC- 

 ITY AND LIGHT 



XXXIV August Weismann (1834-1914) 334 



THE CONTINUITY OF THE GERM-PLASM AS THE 

 FOUNDATION OF A THEORY OF HEREDITY 



XXXV Sir Norman Lockyer (1836- 



1920) 360 



THE CHEMISTRY OF THE STARS 



XXXVI Robert Koch (1843-1910) 374 



THEORY OF BACTERIA 



