v i CONTENTS. 
CHAPTER XII. 
PAGE. 
On Crystalline and Slaty Cleavage 232 
CHAPTER XIII. 
On Paramagnetic and Diamagnetic Forces..-. 244 
CHAPTER XIV. 
Physical Basis of Solar Chemistry 250 
CHAPTER XV. 
Elementary Magnetism 261 
CHAPTER XVI. 
On Force 281 
CHAPTER XVII. 
Contributions to Molecular Physics 294 
CHAPTER XVIII. 
Life and Letters of Faraday 303 
CHAPTER XIX. 
The Copley Medalist of 1870 320 
CHAPTER XX. 
The Copley Medalist of 1871 325 
CHAPTER XXI. 
Death by Lightning , , 332 
CHAPTER XXII. 
Science and the Spirits 336 
CHAPTER XXIII. 
Reflections on Prayer and Natural Law 342 
CHAPTER XXIV. 
Miracles and Special Providences 348 
CHAPTER XXV. 
On Prayer as a Form of Physical Energy 371 
CHAPTER XXVI. 
Vitality., .. 376 
