ASTRONOMY 



21 



2. Mr. Wheeler made an unsuccessful search for Vulcan 

 with a 5-inch Clark telescope, magnifying one hundred and 

 fifty diameters, and mounted as an alt-azimuth. The space 

 swept over was below and preceding the sun, where Profess- 

 ors Watson and Swift discovered Vulcan. 



3. Mr. J. A. Rogers made five photographs of the corona. 

 The exposures were 3, 5, 10, GO, and 20 seconds. The image 

 of the moon was --$ of an inch in diameter. As the expos- 

 ures were increased, more and more of the corona w T as shown, 

 and the longest exposure gave a corona twenty minutes of 

 arc in extent each side of the sun. 



These photographs show a great amount of detail, and in 

 connection with those of other parties will probably give 

 more information in regard to the minute structure and ex- 

 tent of the corona than has yet been obtained from photo- 

 graphs. 



Professor A. W. Wright determined the plane of polariza- 

 tion of the corona, and the percentage of polarized light pres- 

 ent, and took two photographs. 



Dr. Thorpe determined the magnetic elements of La Jun- 

 ta, and photographed the corona. 



The party under direction of Professor Harkness was sta- 

 tioned at Creston, Wyoming Territory. 



Professor Harkness, assisted by Lieutenant E. W. Sturdy, 

 searched the violet and ultra-violet portions of the coronal 

 spectrum for bright lines, but found none. 



Mr. Alvan G. Clark and Mr. A. "N. Skinner managed the 

 equatorial camera, and obtained six photographs of the coro- 

 na, which are thought to be at least as extensive and as rich 

 in detail as any ever taken. The exposures were, respective- 

 ly, 3, 15, 30, 60, 8, and 5 seconds. 



Professor Otis II. Robinson used the polariscopic camera, 

 and obtained four photographs which distinctly show the 

 polarization of the corona. They are now in the hands of 

 Professor A. W. Wright, who is making a special study of 

 that subject. 



The party under direction of Professor Eastman selected 

 as an observing-station the town of West Las Animas, Col. 



Professor Eastman observed contacts, and, with a single- 

 prism spectroscope attached to a 5-inch equatorial, traced 

 the limit of the substance in the corona which gives the 



