REPORT OP THE SECRETARY. 19 



Since the close of the year the Signal Corps, desiring to avail itself 

 of the assistance of the National Research Council, appointed Dr. 

 R. A. Millikan, third vice chairman and executive officer, and Dr. 

 Charles E. Mendenhall majors in the United States Army. 



PUBLICATIONS. 



The Institution proper issues three series of publications: Smith- 

 sonian Contributions to Knowledge, Smithsonian Miscellaneous Col- 

 lections, and Smithsonian Annual Reports. The publications of the 

 various branches of the Institution issued under its direction include 

 the Annual Reports, Proceedings, and Bulletins of the United States 

 National Museum, including the Contributions from the National 

 Herbarium; Annual Reports and Bulletins of the Bureau of Amer- 

 ican Ethnology; and the Annals of the Astrophysical Observatory. 

 All of the publications of these branches and the Annual Report of 

 the Institution are printed by means of Congressional allotments. 



Smithsonian Contributions to Knowledge. — Of this series, which 

 contains in quarto form the results of studies constituting, important 

 contributions to knowledge, one memoir was published, entitled "A 

 Contribution to the Comparative Histology of the Femur," by Dr. 

 J. S. Foote, of Creighton Medical College, embodying the results of 

 the author's work for a number of years on this subject. 



Smithsonian Miscellaneous Collections. — Of this series, 19 papers 

 forming parts of five volumes were issued, including three papers by 

 your secretary containing the results of his field work in Cambrian 

 geology. The annual Smithsonian exploration pamphlet appears 

 in this series, which describes briefly the work in the field of the 

 Smithsonian scientists and scientific expeditions, illustrated by pho- 

 tographs taken by the explorers in every quarter of the globe. The 

 necessity for a second reprinting, of the sixth revised edition of the 

 Smithsonian Physical Tables indicates the continued usefulness of 

 this work. In this series also appeared the important paper by H. 

 Helm Clayton on the effect of variations in solar radiation on the 

 earth's atmosphere, the possibilities of which for use in forecasting 

 temperature are discussed elsewhere in this report. 



Smithsonian report. — As stated in the report on the publications, 

 Appendix 8, although the final proof of the 1916 report was returned 

 to the printer in April, the books were not received before the close 

 of the year because of the great rush of war printing at the Govern- 

 ment Printing Office. 



Special publications. — Among the special publications may be men- 

 tioned an illustrated folder describing the Smithsonian and its 

 branches, for the use of visitors and correspondents. 



