PREFACE ix 



what may be expected. The reader will have frequent 

 opportunities to compare the different scientific points of 

 view that are connected with the theoretical views here 

 exposed with those founded on other theoretical consid- 

 erations. 



I am deeply indebted to my friend Professor Alonzo 

 Engelbert Taylor of Berkeley, California, for his great 

 kindness in the revision of the manuscript and for the cor- 

 rection of some errors. 



To my many friends in California, these lines will, I 

 hope, recall the pleasant period of time during which I 

 had the good fortune to live with them in their agreeable 

 country. 



SVANTE ARRHENIUS. 



STOCKHOLM, SWEDEN, 

 October, 1906. 



