Ralph E. Wilson

THE SPECTRUM OF BD+67°922

Attention was called in the preceding number of these Publications to the peculiar spectrum of BD-f-67°922 (R.A. 16 1*0, Decl. +67° 4, 1900.0, vis. mag. 10.3). During August and September three spectrograms of this star were obtained, one by A. H. Joy with a dispersion of 120 A/mm at Hy and two by R. E. Wilson with a dispersion of 75 A/mm. Thirteen emission lines are visible on all three plates, the relative intensities being roughly as follows :

THE MOTIONS OF THE MAGELLANIC CLOUDS

In 1917 I called attention1 to an apparent systematic difference between the radial velocities of the gaseous nebulae in the northern and southern parts of the Large Magellanic Cloud, suggesting that this difference might result from a rotation of the cloud. In 1920 Hertzsprung proposed2 the simpler explanation, namely, that all parts of the cloud are moving parallel and with the same speed in space. He determined the co-ordinates of the space motion from the radial velocities of the 17 nebulae in the Large Cloud, and showed that the velocity of the single nebula observed in the Small Cloud is consistent with the supposition that the two clouds share the same motion. This was before anything was known about the effects of galactic rotation on radial velocities. It is now clear that the rotation of the galaxy accounts for the major part of the velocities measured in both clouds. Yet, after corrections for galactic rotation (Table I, column 5) are applied, there remain residual velocities which vary roughly with galactic longitude (Table I, column 6). The exact value used for the constant of galactic rotation is not important. We have used 275 km/sec. Any reasonable increase or decrease of this value will produce a decrease or increase in the mean residual velocity, but will always leave a difference in the means for groups of smaller and of greater longitudes. This fact leads one to inquire whether or not the comparatively small residuals remaining after correction for galactic rotation suffice to determine the space motion of the Large Cloud or to give any evidence that the two clouds share the same motion.

A NEW GENERAL CATALOGUE OF RADIAL VELOCITIES

The rapid accumulation of stellar radial velocities in the years following the publication in 1932 of the late J. H. Moores comprehensive catalogue has created among investigators a generally felt need for a new compilation. The present seems a logical time for publication, for it marks approximately the semicentennial of radial-velocity work. It also marks the start of a new era in astronomy in which the primary emphasis changes from stellar motions and the dynamics of the stellar system to the application of new techniques for the study of stellar atmospheres. Of the twenty astronomical observatories credited at some time or other with radial-velocity determinations, only five are still active, and four of these at present contemplate no extensive programs of this kind. It seems likely, therefore, that a catalogue brought up to date now should be useful for a good many years. Like Topsy, this catalogue just growed. Having in mind a series of studies of stellar motions and mean absolute magnitudes of stars with small parallaxes, I began in the late thirties to interline additions to the Moore catalogue. By 1941 a card file became necessary, and since that time this has been kept up to date. As many of you know, Dr. Moore had for some years prior to his death planned a revision of his catalogue, and he and Mrs. Moore kept their files complete up to the end of 1947. When it appeared that he would not be able to carry out his plans and found that I was willing to undertake the work, he turned his files over to me. Comparison of the two sets of records has afforded a valuable check on the completeness of the material and on the copying of the data. With the backing of the successive directors of the Mount Wilson Observatory, financial support of the publication was secured from the Carnegie Institution of Washington. The proposition was presented, discussed, and approved by the Commission on Radial Velocities of the International Astronomical Union at Zurich, Switzerland, in 1948. Letters were sent to the directors of the observatories still active in radial-velocity work requesting any observations they

Meeting of the International Astronomical Union

In a delightful setting overlooking a backdrop of lakes and snow-capped mountains, the International Astronomical Union held its first complete session in ten years at Zurich, Switzerland, August 10-18. Nearly four hundred astronomers and members of their families gathered from all parts of the world to consider the problems of international co-operation in astronomical research and to enjoy the famed hospitality of the Swiss. The largest delegations came from France, with 63 representatives ; England, 62 ; and the United States, 57. The representation of other countries was as follows : Belgium, 30 ; Switzerland, 25; Holland, 23; Italy, 23; Sweden, 17; Poland, 11 ; Czechoslovakia, 9; Denmark, 8; Spain, 8; Russia, 7; Australia, Canada, Germany, Hungary, Ireland, each 6 ; Argentina, 5 ; Algiers, 3 ; the Vatican, 3 ; Austria, Egypt, Finland, Greece, Norway, Portugal, Roumania, South Africa, Yugoslavia, each 2; Bulgaria, 1 ; and China, 1. All the general assemblies and meetings of the 39 constituent commissions were held in the Swiss Federal Institute of Tech-

THE REFORM OF THE CALENDAR

During the early part of 1912 a letter was put into circulation by the Swiss Minister at Washington, asking the opinion of the scientific and commercial men of this country upon a reform of the Gregorian calendar proposed by Professor L. A. Grosclaude, of Geneva, Switzerland. For several centuries the correlation of the day, week, month, and year, as presented in the Gregorian calendar, has been unsatisfactory, and many schemes of reform have been suggested. No one of them, however, has met with enough favor to justify its universal adoption. According to the Encyclopaedia Britannica the objects sought in the making of a calendar are the preservation of the beginning of the year at the same distance from the solstices or equinoxes and the equable distribution of days among twelve months. The Gregorian calendar does very well in satisfying these demands if we exclude the February fiasco, but now we may add another requirement namely, that each day of the week shall occur on the same dates in successive years. The problem, then, presents itself in this form : the year contains 365J4 days, is divided into twelve months and approximately into fifty-two weeks of seven days each; correlate the week, month, and year so that the days of the week will fall on the same dates year after year. Clearly this can only be done by the method of intercalation, and in practically every one of the thirty or more reforms proposed since 1900 the intercalation has been made at the end of the year. New Years Day is observed as a commercial holiday in nearly every part of the civilized world. If, then, we consider that day as an international holiday, known only as New Years Day, and give to it neither week name nor monthly date, no serious inconvenience would be caused in the business world. For recording historical events the day would be known as New Years Day, 1912, 1913, or whatever the year might be, so there would be no inconvenience in chronology. The Julian date is used exten-