CONTENTS 
Pago 
Botany. — Dynamical Aspects of Photosynthesis 
By W. J. V. Ost&rhout and A.R.C. Haas 85 
Physics. — Mobilities of Ions in Air, Hydrogen, and Nitrogen 
By Kia-Lok Yen 91 
Physics. — Thermo-Electric Action with Dual Conduction of Electricity . . . 
By Edwin H. Hall 98 
Physics. — Terrestrial Temperature and Atmospheric Absorption By C. G. Abbot 104 
Physics. — Mobilities of Ions in Vapors ......... By Kia-Lok Yen 106 
Petroiogy. — A Contribution to the Petrography of the South Sea Islands . . 
By J. P. Iddings and E. W. Motley 110 
Physiology.— The Law Controlling the Quantity and Rate of Regeneration . . 
By Jacques Loeb 117 
National Research Council. — Minutes of Executive Board of War Organi- 
zation . 122 
