CONTENTS 
Page 
Astronomy. — Internal Motion in the Spiral Nebula Messier 33 ... . 
By A . van Maanen 1 
Physics.— The Attachment op Electrons to Neutral Molecules in Air . . 
By L. B. Loeb 5 
Physiology. — The Basal Metabolism op Girls 12 to 17 Years op Age . . 
By F. G. Benedict, M. F. Hendry and M. L. Baker 10 
Physics. — On the Reflection and Re-emission op Electrons prom Metal 
Surfaces : and a Method of Measuring the Ionizing Potential of 
Such Surfaces By R. A. Millikan and I. G. Barber 13 
Anthropology. — Chronology of the San Juan Area . v By E. H. Morris 18 
Geology. — Some Geologic Conclusions from Geodetic Data . .By W. Bowie 23 
Chemistry. — Experiments on the Electrical Conduction of a Hydrogen 
Alloy By D. P. Smith 28 
Botany* — The Vascular Anatomy of Normal and Variant Seedlings of 
! Phaseolus vulgaris By J. A. Harris and E. W. Sinnott 35 
Zoology. — The Present Status op the Long-Continued Pedigree Culture 
of Paramecium Aurelia at Yale University . . . By L. L. Woodruff 41 
