18 REPOET OF THE ACTING SECRETAEY, 



form of the bulletin, known as the " Special Bulletin," has been 

 adopted in a few instances in which a larger size of plate was deemed 

 indispensable. Since 1902 the volumes of the series known as " Con- 

 tributions from the National Herbarium." and containing papers 

 relating to the botanical collections of the Museum, have been pub- 

 lished as bulletins. 



The annual report of the ^luseum is printed as a separate volume 

 of the report of the Board of Regents to Congress. 



The publications of the Bureau of American Ethnology, consist- 

 ing of annual reports and bulletins, relate to the operations of the 

 Bureau in its various branches of exploration and research. The 

 most important work now in course of printing is a bulletin in two 

 volumes entitled '* Handbook of the Indians," which will contain a 

 summary of all the information collected regarding the Indian tribes 

 of the United States, arranged in alphabetical sequence for conven- 

 ience of reference. 



Volume I of the Annals of the Astrophysical Observatory was pub- 

 lished in 1900. A second volume, which has been in preparation 

 for some time, is nearly ready for the press. It will discuss the con- 

 tinuation of the work of the Observatory in "Washington and also 

 the investigations on solar radiation conducted by a Smithsonian 

 party at the solar observatory of the Carnegie Institution on Mount 

 Wilson, California. 



Two memoirs by the late Secretary Langley, entitled " Experi- 

 ments in Aerodynamics " and '' The Internal Work of the Wind," 

 were printed in 1891 and 1893. respective!}', as part? of Volume 

 XXVII of the Smithsonian Contributions to Knowledge. A third 

 paper, dealing with later experiments on the same subject, was to 

 complete the volume. At the time of Mr. Langley 's demise the man- 

 uscript was mostly prepared, but it required revision and the writing 

 of several chapters on the engineering part of the work; and by an 

 arrangement with ]Mr. Charles M. Manly, who was for a number 

 of years ^Ir. Langley's chief assistant in aerodynamics, the memoir 

 has been placed in his hands for completion. 



The Annual Report of the American Historical Association for 

 ihe year 1905 was transmitted to Congress on May 14. 1906, under the 

 requirements of the act of incorporation of the association. The 

 Smitlisonian Institution is by law allowed a number of copies of the 

 reports of this association, which are distributed in exchange for the 

 publications of various foreign and American historical societies. 



There was also forwarded to Congi-ess the eighth re]3ort of the 

 National Society of the Daughters of the American Revolution, in 

 accordance with the act of incorporation of that organization. 



In order that the practice of the Institution in the supervision of 

 its publications might correspond with that of the Executive Depart- 



