Professor Fernando Sanford, 

 Dr. Frank Schlesinger. 

 Professor Arthur Schuster. 

 Professor K. Schwarzschild, 



Professor F. H. Seares. 

 L>r. V. M Slipher, 

 Professor Frederick Slocum, 



Ruth E. Smith. 

 Professor S. W. Stratton. 

 Professor H. Struve. 

 Professor S. D. Townley. 

 Professor H. H. Turner, 

 Miss Louise Ware. 

 Miss Phoebe Waterman. 

 Professor F. R. Watson, 

 Professor H. C. Wilson. 

 Professor A. Wolfer. 



Leland Stanford Jr. University. 

 Allegheny Observatory. 

 Victoria Park. 

 Astrophysikalisches Observa- 



torium. 

 Mt. Wilson Solar Observatory. 

 Lowell Observatory. 

 Yerkes Observatory. 

 Mt. Wilson Solar Observatory. 

 Bureau of Standards. 

 Koenigliche Sternwarte. 

 Leland Stanford. Jr.. University. 

 Universitv Observatory. 

 Mt. Wilson Solar Observatory. 

 Mt. Wilson Solar Observatory. 

 University of Illinois. 

 Goodsell Observatory. 

 Sternwarte des Eidgenossischen 

 Polytechnikums, 



Palo Alto. Cal. 

 Allegheny. Pa. 

 Manchester. England. 

 Potsdam. Germany. 



Flagstaff. Ariz. 

 Williams Bay. Wis. 



Washington. D. C. 

 Berlin. Germany. 

 Palo Alto. Cal. 

 Oxford, England. 



Champaign, 111. 

 Xoithneld, Minn. 

 Zurich. Switzerland. 



Accredited Visitors. 



John D. Hooker. Los Angeles, donator of 100-inch lens. 

 Wm. H. Knight. Los Angeles, astronomk-al writer. 

 Edgar L. Larkin. Lowe Observatory, Echo Mountain. Cal. 

 Dr.^ James D. Maddrill. Ukiah Observing Station. Cal. 

 Dr. Ephraim Miller, University of Kansas. 

 Rev. Jerome 8. Eicard, Santa Clara College. 



The Instrumental Equipment on Mount Wilson consisted of: 

 Tli- 60-inch reflecting telescope, mounted in a steel 

 observatory 75 feet in diameter, with double walls to equalize 

 the temperature, and actuated entirely by the touch of an 

 electric button. Accessories to it were plate holders for direct 

 photography, and a device for producing an 18-foot stellar 

 spectograph. Some of the cluster photographs taken by Prof. 

 Ritchey excel in delicate detail anything produced by any 

 other instrument. 



The Snow Horizontal telescope has a mirror of 24 inches 

 aperture, and a focal length of 60 feet. Accessories, an 18-foot 

 solar spectograph, a 5-foot spectroheliograph, and a device for 

 direct photography of the sun. 



The 60-foot Tower Telescope, with an objective of 12 

 inches aperture. Accessories, a 10-foot solar spectograph. for 

 the study of sunspot spectra, spectrum of the chromosphere, 

 etc., and a 10-foot spectroheliograph. 



The new 150-foot Tower Telescope, unfinished, will give 

 a solar image 17 inches in diameter. I believe the largest pro- 

 duced elsewhere is 8 inches. Accessories, combined spectro- 

 graph and spectroheliograph with prisms and gratings of a 

 wide range of dispersion. It will be equipped with apparatus 

 for the study of magnetic fields in sunspots. 



Those directly concerned in these investigations are : 

 George E. Hale, Ferdinand Ellerman, Walter S. Adam-. 

 Edward A. Fath. Arthur S. King. Charges E. St. John. W. G. 

 Ritchey, Harold D. Babcock. F. H. Seares. Henry O. Gale. 



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