Four foreign astronomers, directors and staff members of observatories in Canada, Norway, Holland, and Poland, have arrived at the Harvard Observatory to carry on researches in a number of fields, it was announced yesterday. Five men visiting from other nations have just left after pursuing their researches with the aid of the Observatory staff, it was also learned.

Dr. J. S. Plaskett, director of the Dominion Astrophysical Observatory, Victoria, B. C., has just arrived at Harvard to spend two or three weeks. He is a special student of the rotation of the Galaxy, and has in his charge the second largest telescope in the world, the property of the Government of Canada. Dr. Plaskett is the father of Professor H. H. Plaskett of the Harvard Observatory.

Director at Oslo Lecturing Here

Professor Svein Rosseland has been called to Harvard as Lecturer in Cosmic Physics for one year. He is Director of the University Observatory at Oslo, Norway, and is one of the leading men of Europe in theoretical astrophysics. He is lecturing in Astronomy 11 here, a theoretical course in cosmic physics.

Mr. Bart J. Bok, of Kapteyn Astronomical Laboratory in Groningen, Holland, has joined the Observatory staff for one year to carry out researches in spectrophotometry and stellar statistics. Dr. Leon Hufnagel, of Poland, has returned to the Harvard Observatory for a few months to continue his astrophysical researches. Dr. A. Pannekoek, director of the Astronomical Institute of the University of Amsterdam, visited the Harvard Observatory for a few days in October in the interest of his researches on the structure of the Milky Way.

Returns to Russia After Three Years

Professor E. A. Milne, of Oxford University, spent several weeks at the Harvard Observatory, delivering two lectures and holding many conferences with the staff on subjects of theoretical astrophysics. Dr. Albrecht Unsold, of the University of Munich, spent some weeks at the Harvard Observatory, holding special conferences on line contours and in photometric studies, using Harvard photographs of the structure and distance of the Coal Sack in the southern Milky Way.

Dr. Theodore Dunham '21, of the Mount Wilson Observatory, has left, and Professor Boris Gerasimovic has returned to Kharkov, Russia, after spending nearly three years at the Harvard Observatory as research associate.