The spectra of several stars are being photographed at the observatory. The first of these spectra to be completed is that of Zeta Ursae Majoris. The spectrum of this star has been photographed at the observatory on seventy nights and a careful study of the results has been made by Miss A. C. Maury, a niece of Dr. Draper. The K line is clearly seen to be double in the photographs taken on March 29, 1887, on May 17, 1889, and on August 27 and 28, 1889. On many other dates the line appeared hazy as if the components were slightly separated, while at other times the line appears to be well defined and single. An examination of all the plates leads to the belief that the line is double at intervals of fifty two days, beginning March 27, 1887, and that for several days before and after these dates it presents a hazy appearance. The doubling of the line was predicted for October 18, 1889, but only partially verified. The line appeared hazy or slightly widened on several plates but was not certainly doubled. The star was however low and only three prisms could be used, while the usual number was four. The predicted time when the line should be again double is January 30, 1890.

The library of the observatory has been increased during the past year by the addition of 484 volumes, and 336 pamphlets. The relatively small increase in pamphlets is explained by the fact that large numbers of pamphlets have been bound in volumes. An actual count of the works to be found in the library on November 1, 1889, showed the total number of volumes and pamphlets to be 6,456, and 6,125. The corresponding number found by adding the increase above stated to the total given in the report of the university librarian for last year are 4,583 and 7,911.