Herr Belopolsky contributes to the Astrophysical Journal for December the results of his investigation at Pulkova of the spectrum of P Cygni. In this star, which shows the hydrogen and other lines both bright (Ic2 in the Potsdam classification) and dark, the bright lines are seen to be about in coincidence with the comparison lines, while the dark lines are strongly displaced toward the violet. Herr Belopolsky finds a bright and dark line in the star's spectrum corresponding to each of the several comparison air lines due to nitrogen.

In the Observatory for December, Mr. Newall announces his confirmation of Professor Campbell's discovery that Capella is a spectroscopic binary; and states that before Professor Campbell's note on the subject had been received in England he had presented a short preliminary note to the Royal Astronomical Society to announce the binary nature of the star.

Dr. Wilsing describes in the Astrophysical Journal for December the Potsdam photographic photometer, with which his measures of the relative albedo of Mars and Jupiter were made.

In the conferring of the British new year's honors, Captain William deW. Abney, whose researches in photography are well known to students of the science, and who was the first to photograph the infra-red of the solar spectrum, was designated a Knight Commander of the Bath (K. C. B.).

In his letter to the Board of Visitors to the Naval Observatory at Washington Professor Brown, writing in anticipation of his recent appointment to the position of Astronomical Director of the Observatory, states that the necessary accessories have been provided to enable the Naval Observatory to join in the work of determining motions of stars in line of sight, and that such observations are now a part of the routine work of the Observatory. He expresses his opinion that the time of the 26-inch telescope should be divided equally between this work and micrometric measures.

The Astrophysical Journal for December contains a short note by Professor Young on his original mistaken identification of the corona line with the 1474 chromosphere line. He states that his plan of placing the micrometer wire on the corona line, at the last moment, to fix its position was frustrated both in 1870 and in 1878 by the premature ending of totality.

PLANET NOTES FOR FEBRUARY.

H. C. WILSON.

Mercury will be behind the Sun during this month, passing superior conjunction Feb. 9, and coming out so as to be visible as evening star in the last days of the month. Mercury passes Mars on the morning of Feb. 3, when both planets will be invisible.

Venus is exceedingly brilliant now in the early evening, and may be seen with the naked eye at any time in the afternoon if one knows just where to

EAST HORIZON

direct the eye. Her position is becoming more favorable all the time and her
brightness steadily increasing, while she now outshines many fold any of the
stars. Observations, however, must be made early in the evening, preferably
before sunset, for Venus sets at about 8 o'clock on Feb. 1 and at about 9 o'clock
at the end of the month.

Mars was at conjunction with the Sun Jan. 15 and moves so slowly, relative to the Sun, that he will not be observable for several months.

Jupiter will be at quadrature, 90° west from the Sun, Feb. 28, and so may be observed in the morning an hour or two before sunrise. The altitude of Jupiter will, however, be too low for favorable observations.

Saturn may also be seen in the morning toward the southeast but in less favorable position than that of Jupiter, so that most of us will wait until the spring and summer months for our study of this wonderful planet.

WEST HORIZON

Uranus is in Scorpio between Jupiter and Saturn (see chart in Jan. 1900 No. of POPULAR ASTRONOMY, p. 39), and so to be seen under the same unfavorable conditions.

Neptune is the only planet which can be seen in the evening at a high altitude. This planet requires a powerful telescope to show its disc, but it may be seen and its movement noted with a telescope of three or four inches aperture. It is to be found in the region northeast of the star Tauri, R. A. Feb. 1, 5h 36m 12, Decl. + 22° 3'; Feb. 28, R. A. 5h 35m 28, Decl. + 22° 4′.

AUTHORITIES FOR THE ABOVE EPHEMERIS. The dates for the ephemeris of long-period variables are taken from M. Loewy's ephemeris as published in the Companion to the Observatory for 1900. The magnitudes are taken from Chandler's Third Catalogue for the stars contained in it, for the remainder they are taken from later announcements in the Astronomical Journal, or from personal observations. For the Algol-stars, the ephemeris for S Velorum and RS Sagittarii was computed from the elements in Chandler's Third Catalogue; for W Delphini from the same source; for +12° 3557 from Luizet's elements in No. 3596 of the Nachrichten; for + 45° 3062 from Professor Pickering's elements in No. 3581 of the Nachrichten. The data for the rest of the Algol-stars were taken from M. Loewey's ephemeris in the Companion to the Observatory, but the times there

given are not the ordinary Astronomical Time, reckoning from noon to noon, but reckoned from the previous midnight, as for civil time, so that 12b must be subtracted from the times as above given, to reduce to Greenwich Time. This matter was evidently overlooked by the editors of the Companion, for the statement is made in the introduction, “Greenwich Mean Time is used in all cases, and the astronomical day is reckoned from noon to noon as in previous years."

Minima of the Variable Stars of the Algol Type.

(Given to the nearest hour in Greenwich Time.)

SS CYGNI. The abnormal maximum which was described in the January number of this magazine, has evidently made no interruption in the regular order of procedure with this remarkable star, for it rose suddenly to a maximum of the usual type some time between 1899, Dec. 30, and 1900, Jan. 1. Mr. Sperra fixed the above limits. I found it normal Dec. 29 and bright, about 8.6 magnitude Jan. 1.5. Mr. Flanery found it bright Jan. 2. This rise is about a week earlier than the ephemeris time given in Vol. VII, page 149, a correction quite comparable with those deduced from late maxima. In the table at the top of page 47 in the January number there should be 14 observations by J. A. Parkhurst, instead of 41.

DENSITIES OF ALGOL-TYPE VARIABLES. In the Astrophysical Journal for December, 1899, there are two interesting articles on the above subject, by Alexander Roberts and Henry Norris Russell. Mr. Russell says in introduction: "It is possible in the case of an Algol-star, assuming the eclipse theory of its variation, and a circular orbit, to deduce a limiting value for its mean density