CONTENTS 

 I. HISTORICAL ESSAYS 



PAGE 



THE EARLY DAYS OF CHEMISTRY ... 1 

 THE GREAT LONDON CHEMISTS 



I. BOYLE AND CAVENDISH . . 19 



II. DAVY AND GRAHAM . . 41 



JOSEPH BLACK: HIS LIFE AND WORK . . .67 



LORD KELVIN .... 89 



PIERRE EUGENE MARCELLIN BERTHELOT . 101 



II. CHEMICAL ESSAYS 



HOW DISCOVERIES ARE MADE . . . .115 



THE BECQUEREL RAYS .' 129 



WHAT IS AN ELEMENT? . . . . 147 

 ON THE PERIODIC ARRANGEMENT OF THE ELEMENTS . 161 



RADIUM AND ITS PRODUCTS . . . 179 



WHAT IS ELECTRICITY? ... 193 



THE AURORA BOREALIS .... 205 



THE FUNCTIONS OF A UNIVERSITY . 227 



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