REPORT OF THE SECRETARY. il 
to Knowledge, in quarto, and Smithsonian Miscellaneous Collections, 
in octavo form. The editions of these series are necessarily limited 
in number for distribution almost entirely to a carefully selected 
list of libraries throughout the world, where they may be readily 
consulted by students and investigators. There is also issued, at the 
cost of Government appropriations, an annual report, in the general 
appendix of which is included a considerable number of papers, 
either original or selected from more or less inaccessible sources, 
reviewing the progress and present condition of the natural and 
physical sciences and other branches of human knowledge. AlI- 
though the edition of the report is considerable, yet the supply is 
each year exhausted within a very short time after its publication. 
Contributions to Knowledge—The Langley Memoir on Mechanical 
Flight, referred to in my last report, had been put to press and was 
nearly ready for distribution at the close of the fiscal year. This 
work forms a quarto volume of over 300 pages and a hundred plates. 
The memoir was in preparation at the time of Mr. Langley’s death 
in 1906 and part of it had been written by him, bringing the work 
down to May, 1896, the date of his demonstration that a machine 
heavier than air could be made to fly under its own power. The 
account of later experiments, from 1897 to 1903, was written by Mr. 
Charles M. Manly, who became Mr. Langley’s chief assistant in 1898. 
Miscellaneous Collections Twenty papers on various subjects have 
been added to the series of Smithsonian Miscellaneous Collections, 
including descriptions of a number of new species of animals ob- 
tained by the Smithsonian African expedition and the biological 
survey of the Panama Canal Zone, and several papers, mentioned 
elsewhere, giving some results of my studies and field work in 
Cambrian geology and paleontology, besides an interesting paper 
by Dr. Hrdlicka on his anthropological investigations in Peru. 
Smithsonian Tables——In connection with the system of meteoro- 
logica! observations established by the Smithsonian Institution about 
1850, a series of meteorological tables was compiled by Dr. Arnold 
Guyot at the request of Secretary Henry, and the first edition was 
published in 1852. Though primarily designed for meteorological 
observers reporting to the Smithsonian Institution, the tables were 
so widely used by physicists that it seemed desirable to recast the 
entire work. It was decided to publish three separate sets of tables, 
each containing the latest knowledge in the field which it covered, 
but together forming a homogeneous series. The first of the new 
series, Meteorological Tables, was published in 1893; the second, 
Geographical Tables, in 1894; and the third, Physical Tables, in 
1896. In 1909 another volume was added, so that the series now 
comprises: (a) Smithsonian Meteorological Tables, (2) Smithsonian 
Geographical Tables, (¢) Smithsonian Physical Tables, and (d) 
