PREFACE 



KCE my last volume, Comptes Rendus of Observa- 

 tion and Reasoning, this book contains further 

 "accounts rendered" of work done and things seen at 

 different times, in different places and on different 

 subjects. 



The papers are reproduced in their original form ; 

 and all notes or comments on the papers themselves, 

 as well as reminiscences regarding the circumstances in 

 which they appeared, are embodied in the contents, and 

 occasionally in postscripts to the papers. It is hoped 

 that this arrangement will be of service to the reader. 



J. Y. BUCHANAN. 



July 24///, 1919. 



