CONTENTS 
Page 
Statistics —On the Rate Growth op the Population op the United 
States since 1790 and Its Mathematicai. Representation .... 
By Raymond Pearl and Lowell J. Reed 275 
Physics. — On the Springpiei^d Ripi,e and the L€duc Formula .... 
By Arthur Gordon Webster 289 
Chemistry. — ^Alkyl Amides op Isothiocyanacetic Acid 
By Treat B, Johnson, Arthur J. Hill and E. B. Kelsey 290 
Astronomy. — Studies op Magnitudes, in Star Clusters. XI. Frequency 
OP Curves the Absolute Magnitude and Color Index por 1152 Giant 
Stars By Harlow Shapley . . 293 
Mathematics. — On the Distortion in Conpormal Mapping When the Second 
COEPFICIENT IN THE MAPPING FUNCTION HaS AN ASSIGNED VALUE . • 
By T, H. Gronwall 300 
Physics. — On the Connection op the Specipic Heats with the Equation op 
State op a Gas By Arthur Gordon Webster 302 
Chemistry. — Anomalous Osmose By F. E. Bartell 306 
Physics. — A Photographic Method op Finding the Instantaneous Velocity 
OP Sound Waves at Points Near the Source . . By Arthur L. Foley 310 
Mathematics. — Conpormal Mapping op a Family op Real Conics on An- 
other ByT.H. Gronwall 312 
Physics. — Experiments on the Vibration op Am in Conical Horns . 
By A. G. Webster 316 
Genetics. — The Relative Importance op Heredity and Environment in 
Determining the Piebald Pattern op Guinea-Pigs . . . . . . 
By Sewall Wright 320 
Geology. — Fossil Plants prom the Late Cretaceous op Tennessee . . 
By Edward W. Berry 333 
National Research Council. — Notes prom the Minutes op the Meetings 
IN January and February, 1920, op the Executive Board and Interim 
Committee op the National Research Council 335 
Report op the Meetings op the International Research Council 
AND OP THE Appiliated. Unions Held at Brussels, July 18-28, 1919 . . 340 
Report on the Organization op the International Astronomical 
Union 349 
International Research Council 340 
International Astronomical Union 349 
