26 Carnegie; institution of Washington. 



degree of homogeneity. Thus this project must suffer further delay, al- 

 though it is practically certain that the difficulties presented may be ultimately 

 overcome. 



The relations of Research Associates and collaborators of the Institution 

 are so diversified and complex that they are difficult to specify at any given 

 epoch. Individuals who have received direct aid during 

 Investigations of Re- the year to their investigations through grants are men- 

 a^nd CollaboraTors. tioned in the preceding financial section of this report. 

 Those who have received indirect aid through grants made 

 for the publication of their researches are also mentioned in the section just 

 referred to. Many collaborators and assistants have received compensation 

 directly from Research Associates in charge of investigations, while some 

 Research Associates and many collaborators have received no direct com- 

 pensation. It appears to be neither desirable nor practicable at present to 

 seek any higher degree of correlation of this work, since it is carried on by 

 many individuals in many different parts of the world. The best evidences 

 of the quantity and quality of the results accomplished are to be found in 

 the publications listed in part in a subsequent section of this report and more 

 at length in the general bibliography of the year published in the current 

 Year Book. The work of the year has extended to an aggregate of more 

 than twenty different fields of research and has occupied the attention of 

 more than a hundred investigators. Many of these have rendered special 

 reports to be published in the Year Book, while reference is made to the 

 work of many others in the reports of the larger departments of research. 



