The character of the relative motion will be best seen from the accompanying diagram showing the observed positions for each year in which measures were made. The observations of South in 1823, and those of Herschel in 1830-31, are omitted, as they are obviously erroneous in distance. The diagram strikingly illustrates, even with these omissions, the superior accuracy and consistency of the later measures, although the

components were much closer, and more difficult to observe. Where the years are represented by the measures of more than one observer, the mean is taken for the position shown on the diagram.

The interest of this pair is further increased by the proper motion of the system. This is given by Stumpe from Argelander as o" 481 in the direction of 262°95.

The place of this star (1880) is:

Chicago: November 20.

R.A. 13h 43m 38*

Decl. 27° 35'

The Lunar Eclipse, 1892 May 11-12. By G. J. Newbegin.

The night of May 11-12 turned out so exceptionally fine and clear that (though in -16° of declination) the Moon soon became a steady object in the telescope.

With regard to the eclipse, I decided to take a series of photos at about half-hour intervals, and so endeavour to secure a permanent record of its several stages.

The exposures were made at 9 20, 9.50, 10 30, II, 11.30 P.M., 12 midnight, and 12.30 A.M.

The periods of exposure were varied to allow for the decreasing illumination of the Moon, and were respectively 20, 20, 30s, 40, 30, 203, 20o.

The plates were the Ilford Ordinary, developed by hydroquinone.

The instrument by which they were taken is a 9-inch Cooke Equatoreal, aperture reduced to two inches for the whole series. The intervals between the exposures were occupied in developing the plates.

1892 November 11.

Note on an Occultation of DM. +4°.123 (Mag. 6.5) by Mars on 1893 January 14. By A. M. W. Downing, M.A.

Amongst the cases of possible occultations of stars by planets, given by Herr Berberich in Ast. Nach., No. 3131, is one of the occultation of a 6.5 mag. star by Mars on January 14 next. The star will be occulted to observers situated at the Cape and at Durban; and the particulars of the occultation are given below for these observatories, as well as those of the near approach of the planet to the star as seen from Greenwich.

The star's place is taken from the Albany Zone Catalogue (where it is No. 204), the planet's from the Nautical Almanac, from which source are also taken the horizontal parallax and semi-diameter. The latter, as adopted in the Nautical Almanac, is undoubtedly too large-probably o" 6 too large at the distance with which we are here concerned-sɔ that the durations given below are probably too great in a corresponding proportion.

Cape Observatory. Middle of occultation January 14, 6h 52m-9 Cape mean time. Duration, 4m9. Position-angle at immersion, 50°. Position-angle at emersion, 260°. Unfortunately, the Sun does not set at the Cape on this day until 7h 10m Cape mean time.

Natal Observatory. Middle of occultation January 14, 7h 43m-7 Durban mean time. Duration, 4m.9. Position-angle at immersion, 52°. Position-angle at emersion, 258°. At Durban the Sun sets on this day at 7h om Durban mean time.

Greenwich Observatory. Time of nearest approach, January 14, 5h 40m 2 Greenwich mean time. Distance of star from centre of planet at this time, 9"-8. Position-angle, 335°.

1892 December 9.

Photographs of Comet Holmes. By Isaac Roberts, D.Sc., F.R.S.

Two photographs of Comet Holmes have been taken with the 20-inch reflector. The first, on November 18 (last month) between sidereal time oh 30m and 1h 45m, with exposure of 75 minutes; and the second, on the 20th, with an exposure of 30 minutes. The one now presented is an enlargement from the first negative to the scale of 1 millimetre to 30 seconds of arc, the position of the comet then being, approximately, in R.A. oh 43m, Decl. N. 37° 24'.

The photograph shows the comet to be nearly circular in outline, with the n.p. semicircle well defined, but the s.f. side is undefined and shades into invisibility. The diameter of the defined part measures about 12 minutes of arc, and the comet has a well-defined stellar nucleus when viewed with a low magnifying power, but with a magnifying power of 77 diameters on the negative the nucleus is semi-transparent, and shades without a definite boundary into the comet.

From the nucleus projects a dense condensation, resembling a tail, about 6 minutes of arc in length and 80 seconds in breadth, extending in the n.p. to s.f. direction. The tail is straight, not sharply defined at the margins, and shades into invisibility. It ends with the undefined side, and forms a radius to the circle of the comet.

The nucleus measures about 23 seconds of arc in diameter, and 54 secs. preceding it is the star D.M. No. 140 Zone, 37°, R.A. oh 40m 278, Decl. 37° 11' 3, magnitude 9'5, epoch 1855.

The stellar nucleus of the comet, and the tail-like projection from it, are also well shown on the second photograph, with an exposure of 30 minutes.

Elements of Comet Holmes (f 1892). By Edward Roberts, F.S.S.

The following elements of the comet discovered by Mr. Holmes on November 6 have been calculated from the observations of November 9 and November 26, taken at the Royal Observatory, Greenwich, kindly communicated by the Astronomer Royal, and the position measured from a supposed photograph of the comet taken by Mr. Schooling, of Hammersmith, on October 18, between 8 and 9h 30m. The measurements of the photographic plate were made by Miss A. Russell.

Observations of Holmes' Comei (f 1892) made at the Royal Observatory, Greenwich.

(Communicated by the Astronomer Royal.)