Application may now be made for free tickets to the fall series of open nights at the Harvard College Observatory by sending a self-addressed, stamped envelope to "Open Nights", in care of the Observatory. A statement should accompany applications, which can be made for one night only, indicating how many persons are expected to accompany the bearer. Guests will be given an opportunity to look through the telescopes.

Titles of the talks to be given at 7.30 o'clock on the various open nights are as follows: Friday, October 17, "Pluto and Eros" by Professor Anne S. Young of Mt. Holyoke College; Tuesday, October 21, "Measuring Starlight" by Professor E. S. King; Thursday, October 23, "Something about Comets" by Leon Campbell; Tuesday, October 28, "More About Nebulae" by Miss Adelaide Ames; Thursday, October 30, "The Interior of a Star" by Professor H. H. Plaskett. The last four speakers are connected with the observatory. The open nights are being held under the auspices of the Bond Astronomical Club.

Last year visitors to the Observatory numbered in the neighborhood of 2,000, including children from the Cambridge schools, and members of various clubs. A second series of open nights will be held in May or April.

An airmail letter-recently received at the observatory from Professor Leuschner of the University of California transmitted observations made of the new planet Pluto at the Yerkes Observatory of the University of Wisconsin, indicating that the ninth planet, discovered last March, is following the course predicted for it.