93 



17- A Photographic Comparison of the Spectra of the Limb 

 and Center of the Sun. George E. Hale and Walter S. 

 Adams, n pp., 3 pi. 



18. Some New Applications of the Spectroheliograph. George 



E. Hale. 4 pp., i pi. 



19. The Absence of Very Long Waves from the Sun's Spectrum. 



E. F. Nichols. 3 pp. 



20. Spectroscopic Observations of the Rotation of the Sun 



Walter S. Adams. 22 pp. 



2 1 . Sun-Spot Bands which Appear in the Spectrum of a Calcium 



Arc Burning in the Presence of Hydrogen. Charles M 

 Olmsted. 4 pp., i pi. 



22. Preliminary Catalogue of Lines Affected in Sun-Spots. 



Region X 4000 to X 4500. Walter S. Adams. 21 pp 



23. The Tower Telescope of the Mount Wilson Solar Observa- 



tory. George E. Hale. 9 pp., 3 pi. 



24. Preliminary Note on the Rotation of the Sun as Determined 



from the Displacements of the Hydrogen Lines. 

 Walter S. Adams. 6 pp. 



25. Preliminary Note on the Rotation of the Sun as Deter- 



mined from the Motions of the Hydrogen Flocculi. 

 George E. Hale, n pp., 3 pi. 



26. Solar Vortices. George E. Hale. 17 pp., n pi. 



27. The Pasadena Laboratory of the Mount Wilson Solar 



Observatory. George E. Hale. 6 pp., 2 pi. 



28. An Electric Furnace for Spectroscopic Investigations, with 



Results for the Spectra of Titanium and Vanadium. 

 Arthur S. King. 15 pp., 3 pi. 



29. Anomalous Refraction Phenomena Investigated with the 



Spectroheliograph. W. H. Julius, n pp., i pi. 



30. On the Probable Existence of a Magnetic Field in Sun- 



Spots. George E. Hale. 29 pp., 4 pi. 



VOLUME 2. 



31. On the Absorption of Light in Space. J. C. Kapteyn. 9 pp. 



32. The Relative Intensities of the Calcium Lines H, K, and 



X4227 in the Electric Furnace. Arthur S. King. 

 8 pp., i pi. 



33. Spectroscopic Investigations of the Rotation of the Sun 



during the Year 1908. Walter S. Adams. 36 pp. 



34. On the Separation in the Magnetic Field of Some Lines 



Occurring as Doublets and Triplets in Sun-Spot Spec- 

 tra. Arthur S. King. 8 pp., i pi. 



35. The Relative Intensities of the Yellow, Orange, and Red 



Lines of Calcium in Electric Furnace Spectra. Arthur 

 S. King. 8 pp., i pi. 



