98 



COMMUNICATIONS TO THE NATIONAL ACADEMY OF SCIENCES. 

 Reprinted from I he Proceedings of the Academy. 



BEGINNING VOLUME I. 



1 . The Relations Between the Proper Motions and the Radial 



Velocities of the Stars of the Spectral Types F, G, K. 

 and M. J. C. Kapteyn and Walter S. Adams. 



2. Critique of the Hypothesis of Anomalous Dispersion in 



Certain Solar Phenomena. Charles E. St. John. 



3. An Attempt to Measure the Free Electricity in the Sun's 



Atmosphere. George E. Hale and Harold D. Babcock. 



4. Results of an Investigation of the Flash Spectrum Without 



an Eclipse, Region X48oo to X66oo. Walter S. Adams 

 and Cora G. Bur well. 



5. Variability of Spectrum Lines in the Iron Arc. Charles 



E. St. John and Harold D. Babcock. 



6. Photographic Determination of Stellar Parallaxes with tin- 



6o-inch Reflector. Adriaan van Maanen. 

 -. On the Pole Effect in the Iron Arc. Charles E. Si. John 

 and Harold D. Babcock. 



8. Absolute Scales of Photographic and Photovisual Magni- 



tude. Frederick H. Scares. 



9. Unsymmetrical Lines in Tube-Arc and Spark Spectra 



as an Evidence of Displacing Action in these Sources. 

 Arthur S. King. 



i o. The Direction of Rotation of Sun-Spot Vortices. George E. 

 Hale. 



I i. Some Vortex Experiments bearing on the Nature of Sim- 

 Spots and Flocculi. George E. Hale and George P. 

 Luc key. 



12. Nova Geminorum No. 2 as a \Volf-Rayet Star. Waller 



S. Adams and Francis G. Pease. 



13. The Radial Velocities of the more Distant Stars. Walter 



S. Adams. 



PAPERS FROM THE MOUNT WILSON SOLAR OBSERVATORY. 



V. i, Pt. i. Carnegie Institution Publication No. 138. An In- 

 vestigation of the Rotation Period of the Sun by Spec- 

 troscopic Methods. Walter S. Adams and J. B. Lasby. 

 132 pp., 2 pi. 



V. 2. Pt. i. Carnegie Institution Publication No. 153. The 

 Influence of a Magnetic Field upon the Spark 

 Spectra of Iron and Titanium. Arthur S. King. 

 66 pp., 6 pi. 



