126 
NATURE 
[APRIL I, 1915 


Messrs. HENRY SOTHERAN AND Co., of 140 Strand, 
W.C., and 43 Piccadilly, W., have issued in two parts 
—Nos. 754 and 755—a catalogue of important works 
in natural history, including zoology, botany, gar- 
dening, farming, microscopy, and geology. The 
library of the late Prof. Howes is included in the 
collection. Owing to the war, the volumes are being 
offered at very low prices. 
Tue reference in Nature of March 25 (p. 96) to 
“three Englishmen, namely Sir A. Geikie, Sir William 
Ramsay, and Lord Rayleigh,’ who are members of 
seven national scientific societies, has brought the 
inevitable letter from a correspondent suggesting in- 
justice to ‘‘Scots.’’ In the case of Prussia we used 
deliberately the phrase ‘‘men of science in Prussia,’’ 
knowing, of course, that Prof. van’t Hoff, though he 
lives in Berlin, is not a Prussian. It would perhaps 
have been better to have used the word ‘‘ Britons”’ 
instead of Englishmen in the note, or to have said 
“men of science in England,’ as the comparative 
statement holds good only by taking the place of 
residence of each person. 

OUR ASTRONOMICAL COLUMN. 
Comer i915a (MELLIsH).—The following is the 
ephemeris for Mellish’s comet for the current week as 
computed by Messrs. Braae and Fisher-Petersen :— 
12h. Berlin Mean Time. 
R A, (trus) Decl. (true) Mag. 
h. m. s. ; 
Wwlarnejoy iret) agen) Bash eA —I 23:1 
LN over ic BG) I 41-2 85 
» 4 & 25 2) 1 AGI) 
sf 3 9 40 2 211 8-3 
af, SE dos aes TAOS —2 43:2 
The comet is in the constellation of Serpens, and 
lies a little to the west of the star Eta. It is approach- 
ing both the earth and sun, and it will be nearest the 
earth in about the middle of June. Unfortunately it 
will be too far south to be seen from these latitudes, 
but its increasing brightness will make it a conspicu- 
ous object for observers in the southern hemisphere. 
Elements and ephemeris slightly different from the 
above appear in the Lick Observatory Bulletin No. 268. 
Tue NINTH SaTELLITE OF JUPITER.—An account of the 
discovery, observations, and orbit of the ninth satellite 
of Jupiter is given by Seth B. Nicholson in No. 265 of 
the Lick Observatory Bulletin. The discovery of this 
faint object (about 19 mag.) was made with the 
Crossley reflector at the Lick Observatory on plates 
taken on July 21 and 22 of last year. A series of 
photographs was being made to secure positions of the 
faint satellites of Jupiter, and it was on the first plates 
talken for the eighth satellite that the new member was 
found. The plate was so exposed that the photographic 
image of the eighth satellite should not be elongated, 
and a similar exposure was made on the following 
night. A comparison of the two plates indicated the 
image of an almost circular object on both plates near 
the eighth satellite. Further photographs on July 23 
and 24 corroborated the reality of the images in 
question, and in consequence the discovery was pub- 
licly announced. _ The present bulletin is accompanied 
by a plate showing reproductions of the photographs 
taken on July 22, 23, and 24, indicating the eighth 
and ninth satellites. Mr. Nicholson next describes 
NO. 2370, VOL. 95] 



the computation of the orbit of the new body by 
Leuschner’s method, and gives the approximate 
elements calculated by him, together with those of 
the eighth satellite derived by Crawford and Meyer 
for comparison.’ These serve to establish the identity 
of the object and to describe the nature of its orbit. 
The motion, like that of the eighth satellite, is retro- 
grade. 
IX. VII. 
Epoch Os i 8 Hl 
eeealy 278817 GALT OM 
M, 49 28 266 4 
@ 71 10} 67 46) 
§ 309 2319140 240° 2/1908'0 
ZnLiG 7 si} 144 st) 
€ 071630 0°3520 
B O3154 0°'4573 
P 37125 years 2°155 years 
log @ 9°3232 g'2156 
RELATIVE PROPER MOTIONS OF THE PLEIADES.—In the 
Astronomische Nachrichten No. 4790 Dr. R. Triimpler 
gives details of an interesting investigation on the 
relative proper motions of the Pleiades group. The 
work is based chiefly on a previous research (1901) 
by J. Lagrula entitled ‘‘Etude sur les occultations 
d’amas d’etoiles par la lune avec un catalogue normal 
des Pléiades,”’ in which the differential positions of 
102 stars in the Pleiades group in relation to the 
central star of y Tauri were determined. Dr. Triimpler 
derives the following conclusions from Lagrula’s proper 
motions of forty-three stars. The relative proper 
motions of the eleven brightest stars are very small. 
The relative motions of the fainter stars have larger 
velocities than the bright stars, and exceed the limit 
of errors of the determinations. The proper motions of 
the fainter stars indicate a systematic variation from 
those of the brighter stars, or, in other words, the 
system of the fainter stars appears to displace itself 
with regard to the-system of the brightest stars. In 
the case of the fainter stars there is indicated a move- 
ment of rotation in the direction of decreasing position 
angle, one rotation being of the order of two million 
years; the brightest stars appear to take either no 
part or only a very small part in this movement. The 
point of radiation for the proper motions of the 
Pleiades cannot be deduced with certainty. It can only 
be said that from the observed radial velocities of 
the brightest stars the parallaxes of the Pleiades must 
be smaller than 0-1". 
REPORT OF THE STONYHURST COLLEGE OBSERVATORY. 
—The report of the director of the Stonyhurst College 
Observatory for the year 1914 consists for the main 
part of the results of the meteorological, magnetical, 
and seismological observations. Reference to the 
astronomical work accomplished during the past 
year is incorporated under the heading, ‘‘ Report and 
Notes by the Director." These include, first, the re- 
sults of the measures of the disc areas of sun-spots as 
measured from drawings. It is shown that the year 
1913 was the minimum year of sun-spot activity, while 
the year 1912 was the minimum year for the mean 
range of magnetic declination. These results are in 
accordance with those published in this column for 
March 18 (p. 75). An account is also given of the 
expedition to Hernédsand, Sweden, to observe the total 
solar eclipse of August 21, 1914. Reference is made 
to the record of the strong red radiation coronal line 
63743, which is described here as ‘‘a strong member 
of a band or fluting. ...’’ The presence of this 
coronal radiation was first announced by M. Des- 
landres (Comptes rendus, November 16), and was soon 
corroborated by M. Carrasco by the examination of 
his own eclipse spectrograms. 
