EEPOET OP THE SECRETARY. 19 



reports now comprise a library of about 150 quarto and octavo vol- 

 umes covering practically every branch of scientific knowledge, and 

 if to these be added the publications issued under its direction by the 

 National Museum, the Bureau of Ethnology, and the Astrophysical 

 Observatory, the scientific literature produced through the Institu- 

 tion aggregates about 350 volumes, made up of several thousand 

 memoirs and papers. 



The works issued at the expense of the Institution proper are neces- 

 sarily in limited editions, but they are so distributed to the principal 

 libraries throughout the world as to be available for general reference 

 by all who need them. The annual reports, the general appendix 

 of which is made up of selected papers reviewing progress in scien- 

 tific work in all its branches, is a public document, and through the 

 liberality of Congress is published in larger numbers than the other 

 Smithsonian series, although the editions of this more popular work 

 are each exhausted soon after publication. 



In the series of Contributions, reserved for original additions to 

 knowledge, no memoir was issued during the year. 



Langley memoir on mechanical flight. — Two memoirs by the late 

 Secretary Langley, entitled " Experiments in Aerodynamics " and 

 " The Internal Work of the Wind," were printed in 1891 and 1893, 

 respectively, as parts of volume 27 of the Smithsonian Contributions 

 to Knowledge, and several editions of each have since been published. 

 A third memoir, dealing with later experiments to December 8, 

 1903, to be entitled " Langley Memoir on Mechanical Flight," was to 

 complete that volume. This work was in preparation at the time of 

 Mr. Langley's death in 190G, and the manuscript of the first part cov- 

 ering his experiments down to November, 1896, had been written by 

 him and partially revised for press. The further editorial revision 

 of that part and the completion of part 2 to bring the work down to 

 the close of the experiments on December 8, 1903, was placed in the 

 hands of Mr. Charles M. Manly, who had for several years been Mr. 

 Langley's chief assistant in his experiments. The completed manu- 

 script is now nearly ready for the press and it will probably be pub- 

 lished within a few months. 



It is hoped that later it may be practicable to have tabulated and 

 published the extensive technical data of observations of the work- 

 ing of the model aerodromes and various types of engines, propellers, 

 planes, and other apparatus with the use of the pendulum and whirl- 

 ing-arm. 



It is of interest here to note that on August 6, 1907, a French 

 aviator made a flight of nearly 500 feet with a machine of the Lang- 

 ley type. 



° Recent Progress in Aviation. By Octave Chanute. In Journal Western 

 Society of Engineers, vol. 15, No. 2, April, 1910. See also various French and 

 Italian aeronautical periodicals giving some details of these experiments. 



