THE UNIVERSITY OF CHICAGO 

 SCIENCE SERIES, established by the 

 Trusteesof the University, owes its origin 

 to a behef that there should be a medium of 

 publication occupying a position between the 

 technical journals with their short articles and 

 the elaborate treatises which attempt to cover 

 several or all aspects of a wide field. The 

 volumes of the series will differ from the dis- 

 cussions generally appearing in technical jour- 

 nals in that they will present the complete re- 

 sults of an experiment or series of investigations 

 which previously have appeared only in scat- 

 tered articles, if published at all. On the 

 other hand, they will differ from detailed 

 treatises by confining themselves to specific 

 problems of current interest, and in presenting 

 the subject in as summary a manner and with 

 as little technical detail as is consistent with 

 sound method. They will be written not only 

 for the specialist but for the educated layman. 



