TRANSLATOR'S NOTE 



In the translation of Prof. Hueppe s book 

 I have endeavored simply to reproduce the author s 

 ideas with clearness and fidelity. I have added 

 some footnotes and a few references to important 

 and classic papers and to lately published work 

 of interest, without, however, any pretension to 

 completeness. In the main the book is presented 

 as it came from the hands of the author. 



EDWIN O. JORDAN. 



