94 



36. The 6o-Inch Reflector of the Mount Wilson Solar Observa- 



tory. G. W. Ritchey. 12 pp., 4 pi. 



37. Note on the Polarizing Effect of Ccelostat Mirrors. C'Aur/c.s 



E. St. John. 4 pp. 



38. A Further Study of the H and K Lines of Calcium. Arthur 



S. King. 9 pp., 2 pi. 



39. The Zeeman Effect for Titanium. Arthur S. King. 13 



pp., 2 pi. 



40. A Summary of the Results of a Study of the Mount Wilson 



Photographs of Sun-Spot Spectra. Waller S. Adams. 

 41 pp. 



41. Photography of the "Flash" Spectrum without an Eclipse. 



George E. Hale and Water S. Adams. 9 pp., i pi. 



42. On the Absorption of Light in Space. Second Paper. ./. 



('. Kapteyn. 36 pp. 



43. An Investigation of the Displacements of the Spectrum 



Lines at the Sun's Limb. Walter S. Adams. 32 pp.. 

 i pi. 



44. The Absolute Wave-Lengths of the H and K Lines of 



Calcium in Some Terrestrial Sources. Charles E. St. 

 John. 14 pp. 



45. On Certain Statistical Data Which May be Valuable in the 



Classification of the Stars in the Order of their Evolu- 

 tion. J. C. Kapteyn. 12 pp. 



46. The Correspondence between Zeeman Effect and Pressure- 



Displacement for the Spectra of Iron, Chromium, and 

 Titanium. Arthur S. King. 26 pp. 



47. On Some Methods and Results in Direct Photography with 



the 6o-Inch Reflecting Telescope of the Mount Wilson 

 Solar Observatory. G. H'. Ritchey. 10 pp., 6 pi. 



48. The General Circulation of the Mean- and High-Level 



Calcium Vapor in the Solar Atmosphere. Charles E. 

 St. John. 47 pp., 3 pi. 



49. The Spectra of Spiral Nebulas and Globular Star Clusters. 



E. A. Path. 6 pp. 



50. Some Results of a Study of the Spectra of Sirius, Procyon, 



and Arcturus with High Dispersion. Walter S. Adams. 

 8 pp. 



51. Photographic Observations of Prominences. Giorgio Abelti 



and Ruth Emily Smith. 20 pp. 



52. The Zeeman Effect for Chromium. Harold D. Babcock. 



17 pp., 2 pi. 



