REPORTS ON INVESTIGATIONS AND PROJECTS. 



The following reports and abstracts of reports show the 

 progress of investigations carried on during the year, including 

 not only those authorized for 1917, but others on which work 

 has been continued from prior years. Reports of Directors of 

 Departments are given first, followed by reports of recipients 

 of grants for other investigations, the latter arranged according 

 to subjects. 



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