This, publication is issued four times a year, the first numt 

 each volume usually appearing in January. 



Educational institutions, libraries, societies and individuals 

 desiring to be placed on the exchange list should make request to the 

 "Secretary of the University of Colorado, Boulder, Colo.," to whom 

 also should be addressed any correspondence in regard to purchase 

 of single copies. 



All exchanges should be addressed to the "Library of the Uni- 

 versity of Colorado, Boulder, Colo." 



