Feb. 



889] 



NATURE 



399 



observation in 1 781, its distance never very greatly varying from 

 ; '". The motion of A and B round their common centre of 

 ivity does not appear to be disturbed to any appreciable extent 

 the influence of C, which is so placed as not to affect their 

 apparent relative motions, even though a very considerable mass 

 be assigned to it, and as a fact Prof Seeliger finds, for the most 



probable value of the mass of C, "^ — =: 2-386, where l, m, 



1 + m 

 and m' are the masses of A, B, and C respectively. But there 

 is a periodical retrogression of C itself which is most easily 

 accounted for by supposing the presence of a close companion, 

 one hitherto undetected, and therefore either entirely dark, or 

 but faintly luminous. The distance of this companion is pro- 

 bably only a few tenths of a second, the distance of C from the 

 point, So, round which it appears to revolve, and which may be 

 reasonably assumed to be the centre of gravity of itself and of 

 D, the as yet undiscovered fourth member of the family, being 

 only about one-fifth of a second. 



The entire group therefore may be considered as a double- 

 double, the following being the definitive elements derived for 

 the two pairs : — 



For A and B. For C about S,. 



T 



I868-II2 



I09°735 ) 

 80-190 > 



"•135 I 



o"-853 



22-450 



- 6-0898 



1850-0 



1860-127 



7i°-958 / 



109-677 > 



17-352 \ 



o-iio6 



o"-2i7 



- 20-460 



For the motion of S^ round the optical centre of A and B : — 

 Po = 5"'438- 



145^-46 - o°-5i3 {i - 1850-2) 



The concluding portion of this valuable contribution to the 

 study of a most interesting case in stellar physics is devoted to 

 the consideration of personal errors in the observations, and a 

 plate is added giving a graphical representation of the apparent 

 motion of C, and bringing out in a striking manner the evidence 

 the observations afford of the looping of the curve. 



ASTRONOMICAL PHENOMENA FOR THE 



WEEK 1889 FEBRUARY 24— MARCH 2. 



/"POR the reckoning of time the civil day, commencing at 



^ *• Greenwich mean midnight, counting the hours on to 24, 



is here employed. ) 



Ai Greenwich on February 24 

 Sun rises, 6h. 57m. ; souths, I2fi. 13m. 21 'Ss. ; sets, I7h. 30m. : 

 right asc. on meridian, 22h. 31-601. ; deal. 9° i6' S. 

 Sidereal Time at Sunset, 3h. 49m. 

 Moon (New on March i, 22h.) rises, 2h. 59m. ; souths, 

 7h. 13m.; sets, iih. 23m.: right asc. on meridian, 

 I7h. 30 -3m. ; decl. 20° 54' S. 



Right asc. and declination 

 Planet. Rises. Souths. Sets. on meridian. 



h. m. h. m. h. m. h. m. . / 



Mercury.. 6 5 ... ii 2 ... 15 59 ... 21 19-9 ... 12 49 S. 

 Venus ... 8 2 ... 15 2 ... 22 2 ... i 203 ... 11 i N. 

 Mars ... 7 49 ... 14 2 ... 20 15 ... o 211 ... I 46 N. 

 Jupiter... 4 I ... 7 56 ... II 51 ... 18 13-8 ... 23 5 S. 

 Saturn ... 15 17 ... 22 53 ... 6 29*... 9 128 ... 17 21 N. 

 Uranus... 21 40*... 3 4 ... 8 28 ... 13 20*8 ... 7 49 S. 

 Neptune.. 9 49 .. 17 32 ... i 15*... 3 5l'i ... 18 27 N. 

 • Indicates that the rising is that of the preceding evening and the setting 

 that of the following morning. 

 Feb. h 



25 ... J 



Jupiter in conjunction with and 1° 11' south 



of the Moon. 

 Mercury stationary. 



Mercury in conjunction with and 4° 18' north 

 of the Moon. 



Meteor-Showers. 

 R.A. Decl. 



Near )8 Trianguli 

 ,, 5 Virginis 

 ,, a Serpent is 



30 ... 35 N. 



192 ... 2 N. 



235 ... 10 N. 



280 ... 17 S. 



Swift ; streaks. 

 Very swift. 



GEOGRAPHICAL NOTES. 



An Antarctic Expedition is being again talked of. A New 

 Zealand colonist (of Norwegian origin) has come to Europe for 

 the purpose of taking out a contingent of his countrymen accus- 

 tomed to fishing. His object is to endeavour to organize an 

 Antarctic whale fishery. He hopes to equip two steamers with 

 which to explore the region generally, and, if possible, he will 

 leave a contingent of men on Victoria Land, or some other suit- 

 able point, for a whole year. One or more scientific men will 

 be taken, so that if the proposed expedition be carried out we 

 may expect some important results. 



Dr. Hugo Zoller (sent out by the Kolnische Zeitung) has 

 been doing some original exploring work in German New Guinea. 

 He made an excursion for a considerable distance into the in- 

 terior. In November last he ascended the Finisterre Mountains 

 to a height of 9000 feet. Some of the peaks in this and the 

 Bismarck Ranges rise to a height of over io,ooo feet. 



Captain Page, who recently read a paper on the Gran 

 Chaco at the Royal Geographical Society, proceeds shortly to 

 the Argentine Republic for the purpose of thoroughly exploring 

 the Pilcomayo. He will probably be accompanied by a 

 naturalist. 



The French are endeavouring to raise the funds for a Congo 

 railway which will pass entirely through French territory, in 

 opposition to the scheme for a railway from Vivi to Stanley 

 Pool, for which a survey has recently been made by Belgian 

 engineers. The French railway would run from Brazzaville, on 

 the north side of Stanley Pool, to the River Kwilu, 100 kilometres. 

 Steps, it is stated, will be taken to render the Kwilu navigable, 

 and so establish direct communication between the Congo and 

 the Atlantic. 



In a long article in the new number of the Mouvement 

 Ctvgraphiquc, the question of the origin and course of the 

 Lomami, one of the great southern tributaries of the Congo, is 

 discussed. The conclusion is that it is the same river which 

 Cameron crossed far to the south, and which has been crossed 

 at various points further northwards. It enters the Congo some 

 distance below Stanley Falls. Its course is probably about 

 looo miles in length. 



Dr. Oscar Baumann contributes to the February number 

 of Petermann's Metteilungen a short monograph (with map) on 

 the district of Usambara, in East Africa. The monograph 

 ought to be specially interesting to geologists. 



The February number oixh^Scotlish Geographical Magazine con- 

 tains several very useful articles. Colonel Cadell, Chief Commis- 

 sioner of the Andaman Islands, gives a highly interesting account 

 of the group, and especially of its people, who, he maintains, have 

 been very much maligned from the days of Marco Polo down- 

 wards. The people are fast dying out. Dr. Guppy sends a 

 preliminary note on the geological .structure of the Sindang- 

 Barang district on the south coast of Java. Dr. Guppy sums 

 up the structure of the sea-coast of this part of Java as 

 follows : a basis of massive volcanic rocks overlain by sub- 

 marine tuffs and volcanic muds as far as twelve miles 

 from the coast, and by older and allied tuffs farther inland. 

 The upheaval in post-Tertiary times has been very great, and 

 can only be measured by several thousands of feet. Mr. S. P. 

 Ford gives a brief rhtime of our knowledge of the geography of 

 the Transvaal ; and Mr. W. A. Taylor supplies a real want in his- 

 account of the Philppine Islands, coinpifed from various recent 

 sources. 



