REPORT OF THE SECRETARY. 105 



2018. Recent progress in aviation, by Octave Chanute. Pages 145-167, with 

 19 plates. 



2019. Progress in reclamation of arid lands in the western United States, by 

 F. H. Newell. Pages 169-198, with 12 plates. 



2020. Electric power from the Mississippi River, by Chester M. Clark. Pages 

 199-210, with 8 plates. 



2021. Safety provisions in the United States Steel Coi'poration, by David S. 

 Beyer. Pages 211-229, with 11 plates. 



2022. The insolation of an ion, a pi'ecision measurement of its charge, and the 

 correction of Stokes's Law, by R. A. Millikan. Pages 231-356. 



2023. The telegraphy of photographs, wireless and by wire, by T. Thorne Baker. 

 Pages 357-274, with 2 plates. 



2024. Modern ideas on the constitution of matter, by Jean Becquerel. Pages 

 275-290. 



2025. Some modem developments in methods of testing explosives, by Charles E. 

 Munroe. Pages 291-306, with 12 plates. 



2026. Sir William Tluggins. by W. W. Campbell. Pages 307-317, with 1 plate. 



2027. The solar constant of radiation, by C. G. Abbot. Pages 319-328. 



2028. Astronomical problems of the Southern Hemisphere, by Heber D. Curtis. 

 Pages 329-340. 



2029. The progressive disclosure of the entire atmosphere of the sun, by Dr. H. 

 Deslandres. Pages 341-356, with 4 plates. 



2030. Recent progress in astrophysics iu tlie United States, by J. Rosier. Pages 

 357-370, with 8 plates. 



2031. The future habitability of the earth, by Thomas Chrowder Chamberliu. 

 Pages 371-389. 



2032. What is terra firma? A I'eview of current research in isostasy, by Bailey 

 Willis. Pages 391-406. with 3 plates. 



2033. TransiJiration and the ascent of sap, by Henry H. Dixon. Pages 407-425. 



2034. The sacred ear-flower of the Aztecs, by William Edwin Safford. Pages 

 427-431, with 1 plate. 



2035. Forest preservation, by Henry S. Graves. Pages 433-445, with 7 plates. 



2036. Alexander Agassiz, 1835-1910, by Alfred Goldsborough Mayer. Pages 

 447-472, with 1 plate. 



2037. Recent work on the determination of sex, by Leonard Doncaster. Pages 

 473-485. 



2038. The significance of tlie pulse rate in vertebrate animals, by Florence 

 Buchanan. Pages 487-505. 



2039. The natural history of the solitary wasps of the genus Synagris, by E. 

 Roubaud. Pages 507-525, with 4 plates. 



2040. A contribution to the ecology of the adult Hoatzin, by C. William Beebe. 

 Pages 527-543, with 7 plates. 



2041. Migration of the Pacific plover to and from the Hawaiian Islands, by 

 Henry W. Henshaw. Pages 545-559. 



2042. The plumages of the ostrich, by Prof. J. E. Duerden. Pages 561-571, with 

 8 plates. 



2043. Manife.sted life of tissues outside of the organism, by Alexis Carrel and 

 Montrose T. Burrows. Pages 573-582. 



2044. The origin of Druldism, by Julius Pokorny. Pages 583-597. 



2045. Geographical and statistical view of the contemporary Slav peoples, by 

 Lubor Niederle. Pages 599-612, with colored map. 



2040. The cave dwellings of the Old and New Worlds, by J. Walter Fewkes. 

 Pages 013-634, with 11 plates. 



