December 15, 1892] 



NATURE 



59 



rapidly dri^ by means of blotting-paper and placed under the 

 microscope, the Nicols being crossed, it simply produces the 

 usual effect of causing the field to become coloured with some 

 homogeneous tint. But after the expiration of three or four 

 minutes the molecular change begins to be rendered apparent 

 at the circumference of the field by a rapid augmentation of the 

 polarizing effect ; in another moment it commences to dart across 

 the field in all directions, the brilliantly coloured rays being 

 feathered with offshoots, reminding one of the rays of crystal- 

 lizing ammonium chloride. This beautiful effect continues until, 

 in less than ten minutes after the removal of the crystal from the 

 mother liquor, the rearrangement of the molecules has become 

 so general that light is no longer able to penetrate, and the 

 crystal becomes completely opaque. Messrs. Wells and Wheeler 

 have also attempted to prepare the analogous compounds con- 

 taining iodine, but have not yet obtained them in a condition 

 so pure or well crystallised as the salts described above. 



The additions to the Zoological Society's Gardens during the 

 past week include a white-fronted lemur {Lemur albifrons 9 ) 

 from Madagascar, presented by Mr. M. C. Parker ; a brown 

 capuchin [Cebus fahiellus S) from Brazil, presented by Mr. 

 Earle Tudor Johnson ; a large-eared fox {Otocyon megalotis) 

 from Mashonoland, South Africa, presented by Mr. B. B. Weil ; 

 two black-backed jackals {Cants viesomelas) from South Africa, 

 presented by Capt. Ralph H. Carr-EIlison ; a common fox 

 {Cams vulpes ? ) from Arabia, presented by Miss Morgan ; a 

 leadbeater's cockatoo {Cacatua leadbeateri) from Australia, pre- 

 sented by Lieut. -Colonel Warton ; a Rhesus monkey (J/a^racwi- 

 rhesus) from India, deposited. 



OUR ASTRONOMICAL COLUMN. 



Comet Holmes (November 6).— The following is the 

 «phemeris for Comet Holmes for the ensuing week : — 



1802. \^- (*PP)- 



n. m. s. 



Dec. 15 ... o 49 34 



16 .... 50 15 



17 ... 50 57 ■ 



18 ... 51 41 



19 ■■■ 52 27 , 



Decl. (app.). 



+ 34 S'o-i 

 45-8 

 41-6 

 37-5 

 33-6 



20 ... 53 14 ... 29-8 



21 ... 54 3 ... 261 



22 ... O 54 53 ... -f-34 22-6 



Log J 



0*4004 



0-4027 



Log A. 



o 2813 



02931 



Owing to the extremely bad weather, observations of this comet 

 have not been numerous, but from all accounts not much change 

 has taken place in the general appearance, except that the 

 central nucleus seems to possess two small tails, which extend 

 towards the ragged edge of the exterior portion. 



Comet Brooks (November 20, 1892). — Last week the only 

 ephemeris of this comet at hand was one showing its position 

 every fourth day, but Prof. Kreutz has now communicated to 

 Astronomische Aackrichten, No. 3132, a daily ephemeris, from 

 which the following is extracted : — 



1892. ?-^- (»PP-)- 

 * h. in. s. 



Dec. 15... 13 50 10 

 16.... 54 6 



17... 13 58 19 

 18... 14 2 53 



19 •• 7 51 



20... 13 17 



21... 19 13 



22... 25 46 



Decl. (app). Log 



Log A. 



+ 31 57-3 



33 I7'2 ... 0-0974 ••• ooooi .. 3-67 



34 41 '2 



36 9-5 ... 0-0946 ... 9"977S ••• 413 



37 42-2 



39 i9'3 ••• 00921 ... 9-9550 ... 4-63 



41 08 



42 46-6 ... 0-0898 ... 9-9332 ... 5-17 



From the column showing the brightnesses it will be seen that 

 a considerable increase in this comet is taking place. The 

 comet will be easily found by the fact that it lies in the pro- 

 longation of a line joining 3 and 7 Bootis (December 18) at a 

 distance equal to that between those two stars. 



NO. T207. VOL. 47I 



The New Brooks' Comet.— The following positions of 

 this comet are reported from Marseilles, by MM. Esmiol and 

 Fabry : — 



Marseille App. App. 



Date. Mean Time. R.A. P.D. 



h. m. s. h. m. s. - / // 

 Nov. 24 ... 17 45 16 ... 13 3 14-6 ... 74 SI 33 

 24 ... 17 6 S3 ••• 13 4 39'39 ■ ■ 74 33 18-1 



29 ... 16 43 46 ... 13 II 1-76 ... 72 II 46-7 



30 ... 16 41 49 ... 13 12 4577 71 34 49-0 



The comet presented the appearance of a nebulosity about 

 I' in diameter, diffuse at the edges, and brighter towards the 

 centre, but without a well-defined nucleus. Its brightness was 

 about that of a star of eleventh magnitude. 



Nova Aurig/E. — Nova Aurigae has again increased in mag- 

 nitude, observations showing that visibly it is 8-5, while photo- 

 graphically it is three magnitudes fainter. 



Astronomy at Columbia College, U.S.A.— The latest 

 number of the bulletin issued by this college informs us that 

 with the consent of the governing body of the New York 

 Hospital and the college trustees, a new but small observatory 

 is about to be erected on the site Bloomingdale. The instrument, 

 which is at present being constructed by Wauschaff, at Berlin, 

 is a zenith telescope, and it is one of a pair which is going to be 

 used for observations to obtain accurate determinations of the 

 variations of terrestrial latitudes. The other instrument, by 

 order of the Italian government, is going to be mounted at the 

 Royal Observatory of Capodimonte. Both instruments will 

 soon be, if not already, in working order ; the observers in 

 America are Prof. Rees and Mr. Jacoby, while M. Higola will 

 undertake the Italian observations. 



The library of this college has been recently very much in- 

 creased by the purchase of the fine library of astronomical and 

 physical works belonging to Mr. Struve, former director of the 

 Pulkowa observatory. This addition amounts to no less than 

 4361 bound and unbound books, together with 3056 pamphlets. 



Companion to the Observatory for 1893.— This 

 annual Companion for the coming year is very similar to the 

 one last published. Mr. Denning gives a list of the principal 

 meteor showers deduced from recent observations, while 

 ephemerides for the planets, together with their satellites, are 

 also inserted. Solar observers will find the ephemeris given on 

 page 22 very useful, this table giving the position-angle of the 

 sun's axis, and the heliographic latitudes and longitudes of the 

 centre of his disc. In addition to several other handy tables 

 and ephemerides, the times of minima of variable star.s not of 

 the Algol type, variable stars of the Algol type, maxima and 

 minima of variable stars, and finally a table of double stars are 

 also included. 



GEOGRAPHICAL NOTES. 



Major Thys, who has recently returned from the Congo Free 

 State, reports that the railway from Matadi to Stanley Pool is 

 progressing rapidly. The works are practically completed for only 

 14 kilometers out of the 400, but this includes the most difficult 

 region, including the greater part of the ascent to the plateau. 

 In a few months it is hoped that 40 kilometers will be com- 

 pleted, and the malarial coast-belt can then be traversed rapidly, 

 obviating a serious risk to the health of travellers to the Upper 

 Congo. 



We are pleased to find that the Manchester Geographical 

 Society has published the concluding part of the seventh volume 

 of its Journal although, as we had occasion to remark on the 

 appearance of the previous part, it is greatly to be regretted that 

 the people of Manchester do not take a greater interest 

 in a Society which is one they have reason to be proud of. 

 It is, we are convinced, solely to this want of local apprecia 

 tion that the Journal has to be issued so far behind its 

 proper date as to impair the usefulness of its contents. In the 

 current number there is an interesting paper on Japan by Mr. 

 W. M. Steinthal. 



Mr. G. A. Craig has, we understand, resigned the secretary- 

 ship of the Liverpool Geographical Society on account of ill- 

 health. 



The Scotiish Geographical Magazine for this month contains 

 a paper by Captain Lugard, entitled •' Characteristics of African 



