116 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1921. 



The differentiation of mankind into racial types, by Arthur Keith. 



The exploration of Manchuria, by Arthur de C. Sowerby. 



The origin and beginnings of the Czechoslovak people, by JindHch Matiegka. 



Geographic education in America, by Albert Perry Brigham. 



Progress in national land reclamation in the United States, by C. A. Bissell. 



Richard Rathbun, by Marcus Benjamin. 



A great chemist : Sir William Ramsay, by Gh. Monreu. 



REPORT FOR 192 0. 



The report of the executive committee and proceedings of the 

 Board of Kegents of the Institution and report of the secretary, both 

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

 gress, were issued in pamphlet form in November, 1920. 



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

 of the Smithsonian Institution for the year ending June 30. 1020. 19 pp. 

 (Publ. 2£87.) 



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

 June 30, 1920. 110 pp., 1 pi. (Publ. 2586.) 



The general appendix to this report, which was in press at the 

 close of the year, contains the following papers : 



Studying the sun's heat on mountain peaks in desert lands, by C. G. Abbot. 



The habitability of Venus, Mars, and other worlds, by C. G. Abbot. 



Giant suns, by H. H. Turner. 



A bundle of meteorological paradoxes, by W. J. Humphreys. 



The determination of the structure of crystals, by Ralph W.„G. Wyckoff. 



Dr. Aston's experiments on the mass spectra of the chemical elements, with 



introduction by C. G. Abbot. 

 Vitamins, by W. D. Halliburton. 

 Soil acidity — its nature, measurement, and relation to plant distribution, by 



Edgar T. Wherry. 

 The chemistry of the earth's crust, by Henry S. Washington. 

 Major causes of land and sea oscillations, by E. O. Ulrich. 

 The Bryozoa, or moss animals, by R. S. Bassler. 

 The horned dinosaurs, by Charles W. Gilmore. 

 Rhythm in nature, by F. W. Flattely. 

 Parasitism and symbiosis in their relation to the problem of evolution, by 



Maurice Caullery. 

 Local suppression of agricultural pests by birds, by W. L. McAfee. 

 The occult senses in birds, by Herbert H. Beck. 

 Adventures in the life of a fiddler crab, by O. W. Hyman. 

 The senses of insects, by N. E. Mclndoo. 



The resplendent shield-bearer and the ribbed cocoon-maker: Two insect in- 

 habitants of the orchard, by II. E. Snodgrass. 

 The origin of insect societies, by Auguste Lameere. 

 The botanical gardens of Jamaica, by William R. Maxon. 

 Narcotic daturas of the Old and New World; an account of their remarkable 



properties and their uses as intoxicants and in divination, by William E. 



Safford. 

 Effect of the relative length of day and night on dowering and fruiting of 



plants, by W. W. Garner and H. A. Allard. 



