REPORT OF THE SECRETARY. 103 



forming part of the annual report of the Board of Regents to Con- 

 gress, were issued in pamphlet form in December, 1918. 



Report of the executive committee and proceedings of tlie Board of Regents 

 of the Smithsonian Institution for the year ending June 30, 1918. 13 pp. 

 (Publ. 2529.) 



Report of the Secretary of the Smithsonian Institution for the year ending 

 June 30, 1918. 101 pp. (Publ. 2487.) 



The general appendix of the report for 1918, which was in press 

 at the close of the year, contains the following papers : 



1. The Discovery of Helium, and what came of it, by O. G. Abbot. 



2. An Account of the Rise of Navigation, by R. H. Curtiss. 



3. The Tornadoes of the United States, by Prof. Robert DeC. Ward. 



4. Wind Power, by Janes Carlill. 



5. A Tribute. Samuel Pierpont Langley : Pioneer in Practical Aviation, by 

 Henry Leffmann. 



6. Modern Physics, by R. A. Millikan. 



7. The Experiments of Dr. P. W. Bridgman on the Properties of Matter When 

 Under High Pressure. Introductory note, by 0. G. Abbot. 



8. The problem of Radioactive Lead, by Theodore W. Richards. 



9. Sphagnum Moss ; war substitute for cotton in absorbent surgical dress- 

 ings, by Prof. George E. Nichols. 



10. History of Military Medicine and its Contributions to Science, by Col. 

 W. P. Chamberlain. 



11. Some Problems of International Readjustment of Mineral Supplies as 

 Indicated in Recent Foreign Literature, by Eleanora F. Bliss. 



12. Reptile Reconstructions in the United States National Museum, by 

 Charles W. Gilmore. 



13. A Pleistocene Cave Deposit of Western Maryland, by J. W. Gidley. 



14. Paleobotany : A Sketch of the Origin and Evolution of Floras, by Edward 

 W. Berry. 



15. The Direct Action of Environment and Evolution, by Prince Kropotkin. 



16. The Law of Irreversible Evolution, by Branislav Petronievics. 



17. The Fundamental Factor of Insect Evolution, by S. S. Chetverikov. 



18. The Psychic Life of Inse,cts, by E. L. Bouvier. 



19. Sexual Selection and Bird Song, by Chauncey J. Hawkins. 



20. Marine Camoufleurs and their Camouflage : The present and prospective 

 significance of facts regarding coloration of tropical fishes, by W. H. Longley. 



21. Foot-Plow Agriculture in Peru, by O. F. Cook. 



22. Sun Worship of the Hopi Indians, by J. Walter Fewkes. 



23. The League of the Iroquois and its Constitution : A constitutional 

 league of peace in the Stone Age of America, by J. N. B. Hewitt. 



24. The Problem of Degeneracy, by H. F. Tredgold. 



25. History in Tools, by W. M. Flinders Petrie. 



26. The Background of T®temism, by E. Washburn Hopkins. 



27. A Great Naturalist: Sir Joseph Hooker, by Sir E. Ray Lankester. 



SPECIAL PUBLICATIONS. 



The following publication was issued in octavo form : 

 Classified list of Smithsonian pubUcations available for distribution October 

 15,1918. 1918. 31pp. (Publ. 2.524.) 



