CONTENTS 
Page 
Physics.— The Thermo-Electkic Equation P = TdVjdT Once More .... 
By Edwin H, Hdl'\91 
Physics. — On the X-Ray Absorption Wave-Lengths of Lead Isotopes . / . . 
By William Duane and Takeo Shimizu 198 
Botany.— Some Orienting Effects of Monochromatic Lights of Equal Intensi- 
ties ON Fucus Spores and Rhizoids ...... By Annie May Hurd 201 
Mathematics.— On the Most General Class L of Fr^chet in which the Heine- 
Borel-Lebesgue Theorem Holds True By Robert L. Moore 206 
Physics.— An Electrodynamometer Using the Vibration Telescope .... 
By Carl Barus 211 
Physiology.— The Temperature of the Human Skin • 
By F. G. Benedict, W. R. Miles and Alice Johnson 218 
Mathematics.— On a Certain Class of Rational Ruled Surfaces . . ♦ . . 
By Arnold Emch 222 
