CONTENTS. 



I. THE CONSTITUTION OP NATURE, .... 7 



II. THOUGHTS ON PRAYER AND NATURAL LAW, . . 33 



III. MIRACLES AND SPECIAL PROVIDENCES, . . , . 43 



IV. MATTER AND FORCE, . . . . . 71 



V. AN ADDRESS TO STUDENTS, . . . . .95 



VI. SCOPE AND LIMIT OF SCIENTIFIC MATERIALISM, . 107 



. VII. SCIENTIFIC USE OF THE IMAGINATION, . . .125 



VIII. ON RADIATION, . . . . .167 



A IX. ON RADIANT HEAT IN RELATION TO THE COLOR AND CHEMI 

 CAL CONSTITUTION OF BODIES, . . .211 

 X. ON CHEMICAL RAYS AND THE STRUCTURE AND LIGHT OF 



THE SKY, . . . . . . 235 



XI. DUST AND DISEASE, ..... 275 



ADDITION TO &quot; DUST AND DISEASE,&quot; . . . 323 



XII. : LIFE AND LETTERS OF FARADAY, . . . 329 



XIII. AN ELEMENTARY LECTURE ON MAGNETISM, . . 353 



XIV. SHORTER ARTICLES: 



SLATES, ...... 377 



DEATH BY LIGHTNING, .... 397 



SCIENCE AND SPIRITS, .... 402 



VITALITY, . . . . . .410 



ADDITIONAL REMARKS ON MIRACLES, . . 418 



