CONTENTS 
Page 
Physics. — Inferences Concerning Auroras By Elihu Thomson 1 
Biology. — ^Application of the Laws of Action, Reaction and Interaction in 
Life Evolution By Henry Fairfield Osborn 7 
Physics. — The Resistance of Metals Under Pressure . . By P. W. Bridgman 10 
Physiology. — ^The Rate of Discharge of Central Neurones 
By Alexander Forbes and W. C. Rappleye 12 
Physiology. — A Physiological Study of Noctiluca, With Special Reference to 
Light Production, Anaesthesia and Speclfic Gravity. By Ethel Browne Harvey 15 
Geology. — Physiographic Subdivision of the United States 
By Nevin M. Fenneman 17 
Physiology. — On the Composition of the Medusa, Cassiopea Xamachana and 
the Changes in it After Starvation By S. Hatai 22 
Astronomy. — Studies of the Magnitudes in Star Clusters, IV. On the Color 
OF Stars in the Galactic Clouds Surrounding Messier II 
By Harlow Shapley 25 
Astronomy. — The Color of the Standard Polor Stars Determined by the 
Method of Exposure-Ratios By Frederick H. Scares 29 
Geology. — Terracing of Bajada Belts By Charles Keyes 33 
Astronomy. — Relation of the Apex of Solar Motion to Proper Motion and on 
THE Cause of the Differences of its Position From Radial Velocities and 
Proper Motions By C. D. Perrine 38 
Engineering. — ^Hydrology of the Isthmus of Panama 
By Brig. Gen. Henry L. A hhot 41 
Astronomy. — ^The Meteor System of Pons-Winnecke's Comet 
By Charles P. Olivier 47 
Chemistry.— Improvements in Calorimetric Combustion, and the Heat of Com- 
bustion op Toluene , . . » By Theodore W. Richards and Harold S. Davis 50 
Physics. — The Mass of the Electric Carrier in Copper, Silver and Alumi- 
nium ........... jB^; Richard C. Tolman and T. Dale Stewart 58 
Physics. — ^The Silver Voltameter as an International Stan-dard for the 
Measurement of Electric Current . . . By E. B. Rosa and G. W. Vinal 59 
