ADVERTISEMENT 



The present work, entitled " Langley Memoir on Mechanical Plight," as 

 planned by the late Secretary Samuel Pierpont Langley, follows his publications 

 on " Experiments in Aerodynamics " and " The Internal Work of the Wind ' ; 

 printed in 1891 and 1893, respectively, as parts of Volume 27 of the Smithsonian 

 Contributions to Knowledge. 



This Memoir was in preparation at the time of Mr. Langley's death in 1906, 

 and Part I, recording experiments from 1887 to 1896, was written by him. Part 

 II, on experiments from 1897 to 1903, has been written by Mr. Charles M. Manly, 

 who became Mr. Langley's Chief Assistant in June, 1898. The sources of infor- 

 mation for this Part were the original carefully recorded accounts of the experi- 

 ment s described. 



It is expected later to publish a third part of the present memoir, to consist 

 largely of the extensive technical data of tests of the working of various types of 

 curved surfaces, propellers, and other apparatus. 



It is of interest here to note that experiments with the Langley type of aero- 

 drome ' did not actually cease in December, 1903, when he made his last trial 

 with the man-carrying machine, but as recently as August 6, 1907, a French 

 aviator made a flight of nearly 500 feet with an aerodrome of essentially the same 

 design. (See Appendix.) 



In accordance with Ihe established custom of referring to experts in the 

 subject treated, all manuscripts intended for publication in the Smithsonian 

 Contributions to Knowledge, this work was examined and recommended by a 

 Commission consisting of Mr. O. H. Tittman, Superintendent of the United 

 States Coast and Geodetic Survey, who witnessed some of the field trials, George 

 O. Squier, Ph. D. (Johns Hopkins), Major, Signal Corps, U. S. Army, and Albert 

 Francis Zahm, Ph. D., of Washington City. 



Charles P. Walcott, 

 Secretary of the Smithsonian Institution. 



1 The name " aerodrome " was given by Secretary Langley to the flying machine in 1S93, from 

 atpoipo/iiu (to traverse the air) and atpoipdfioc air runner. — Internal Work of the Wind, p. 5. 



