THE UNIVERSITY OF CHICAGO 

 SCIENCE SERIES, established by the 

 Trustees of the University, owes its origin to 

 a belief that there should be a medium of publica- 

 tion 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 discussions generally appearing 

 in technical journals in that they will present the 

 complete results of an experiment or series of 

 investigations which previously have appeared 

 only in scattered articles, if published at all. On 

 the other hand, they will diifer from detailed 

 treatises by confining themselves to specific prob- 

 lems 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. 



