Vol.. 6, 1920 
REPORT OF THE ANNUAL MEETING 
447 
to the Smithsonian Institution and to the Cosmos Club for courtesies 
extended to the members of the National Academy of Sciences during 
the meeting. 
SCIENTIFIC SESSIONS 
A public lecture-discussion in the series of William EIvIvERY HalE 
Lectures was delivered on The Scale of the Universe, on April 26 at 8.15 
P.M., by Harlow ShaplEy, of the Mount Wilson Observatory and by 
Heber D. Curtis, of the Lick Observatory 
Four public scientific sessions were held on Monday and Tuesday, 
April 26-27, at which the following papers were presented : 
John M. Clarke: Conservation of natural resources as a proper function of the 
National Academy. 
Raymond Pearl: On the rate of growth of the population of the United States 
since 1790 and its mathematical expression. 
Franz Boas: Growth and development as determined by environmental influences. 
Charles B. Davenport: Plural births in man. 
Samuel J. MelTzer: The importance of the presence of both sympathetic superior 
cervical ganglia to the maintenance of life; and their possible relations to respiratory 
diseases. 
Charles D. Walcott: Structure of Marrella and allied Middle Cambrian crus- 
taceans. *• 
James R. Angell: The National Research Council. 
Robert M. Yerkes (introduced by E. L. Thorndike) : A psychological study of the 
medical officers in the Army. 
Robert W. Wood: Spectroscopic phenomena of very long vacuum tubes. 
L. T. E. Thompson, C. N. Hickman and N. Riffolt (introduced by Arthur G. 
Webster) : The measurement of small time intervals and some applications, principally 
ballistic. 
Robert A. Millikan: The effect of molecular structure upon the reflection of 
molecules from the surface of liquids and solids. 
Arthur G. Webster: The Springfield rifle and the Leduc formula. 
Arthur G. Webster: Some new methods in internal ballistics of the Springfield 
rifle. 
George B. Hale: The 100-inch Hooker telescope of the Mt. Wilson Observatory. 
A. A. Michelson: (i) The vertical interferometer. (2) Preliminary tests in an 
attempt to measure the diameter of the stars. (3) A modification of the Foucault 
method adapted to long-distance measurement of the velocity of light. 
Arthur G. Webster: Preliminary measurements on the pressures in the "Onde 
de Choc." 
Arthur G. Webster: On the connection of the specific heats with the equation 
of state of a gas. 
Edwin H. Hall: Thermal conductivity of metals. 
C. Hart Merriam: Distribution and villages of the Indian tribes of the Klamath 
river region, California. 
John C. Merriam: Significance of correlation in function between the dentition 
and skeleton of the Sabre- tooth tiger. 
George H. Parker: On the colonial nervous system of Renilla. 
Douglas H. Campbell: The genus Botrychium and its relationships. 
Frederick V. CovillE: The influence of cold in stimulating the growth of plants. 
