498 



NA TURE 



[March 25, 1886 



Guiana, a Sun Bittern [Einypyga hdias) from South America, a 

 Thiclc-necked Tree Boa (Epkrates ceyirhns) from West Indies, 

 purcliased ; three Long-fronted Gerbilles {Gerbilltis longi/ioiis), 

 bom in the Gardens. 



OUR ASTRONOMICAL COLUMN 

 An Observation of Neptune Occurring in Lamont's 

 Zones. — Mr. Hind pointed out in the Astronomische Nach- 

 richten. No. 712, two cases of observations of Neptune occurring 

 in Lamont's zones, in which the planet was mistaken for a star. 

 The dates of these two observations are respectively October 25, 

 184S, and September 7, 1846. Prof. Schonfeld, in No. 2716 of 

 the same publication, draws attention to a third instance in 

 which an observation of the planet occurs in these zones. Tlie 

 date of this observation is September 11, 1846. It will be 

 remembered that Neptune was optically discovered by Galle on 

 September 23, 1846. Prof. Schonfeld thinks it advisable to 

 give publicity to his discovery, lest at any time an astronomer 

 should be led to think that this object, which is entered as 

 No. 381S in the Catalogue in the IMunich Supplementband .\ii. 

 (generally designated Lamont 5), was a " tempofary " star. 



The Armagh Observatory. — We are glad to learn from a 

 report recently issued by Dr. Dreyer, that an equatorial re- 

 fractor by Mr. Grubb, having an excellent object-glass of 

 10 inches aperture, and 10 feet focal length, has been installed 

 in the "Robinson Memorial Dome," erected by the same artist. 

 The instrument has already been brought into use, and a series 

 of micrometric observations of nebulae has been commenced. 

 We trust therefore that, under Dr. Dreyer's superintendence, 

 the Armagh Observatory is now entering en a career of obser- 

 vational activity which will restore it to the position whiili it 

 has formerly held as one of the foremost institutions of its kind 

 in the British Isles. 



Distribution in Latitude of Solar Phenomena. — M. 

 Tacchini, in a note appearing in the Comptes rendiis, vol. cii. 

 No. II, gives a table showing the distribution in heliographic lati- 

 tude of the various classes of solar phenomena in 18S5. The lable 

 is remarkable as still further accentuating the difference seen at 

 the present time in the behaviour of sunspots and prominences 

 (Nature, Feb. 25, p. 398). Not only have the prominences shown 

 little or no diminution in dimensions or frequency during the 

 past year, whilst sunspots and faculas have notably declined, but 

 the prominences are still detected in every latitude from pole to 

 pole, whilst spots, faculre, and metallic eruptions are confined 

 almost entirely, the spots entirely, to latitudes lower than 40°, 

 and in the great majority of instances to latitudes lower than 

 20°. The zones showirig the greatest frequency for prominences 

 are placed considerably further from the equator. There is also 

 a difference in the proportionate distribution of the different 

 classes of phenomena between the two hemispheres, as the fol- 

 lowing table will show : — 



Northern Southern 



heinispliere hemisph'ie 



Prominences ... ... o'478 ... o'522 



Faciilae ... ... ... 0'367 ... o'633 



Sunspots ... ... ... o'336 ... o'664 



Metallic eruptions o'325 ... 0-675 



Thus whilst the southern hemisphere has been about twice as 

 prolific in the last three classes as the northern, there has been 

 a much smaller difference between the hemispheres in the matter 

 of prominences. The result of the comparison, on the whole, 

 tends to show that, whilst there is a close connection between 

 spots and metallic eruptions, ordinary prominences are to a great 

 extent independent phenomena ; indeed whilst, as already men- 

 tioned, stinspots have declined during 1885, prominences have 

 actually been more frequent in the zones in which sunspots have 

 not been seen. 



Prominences and Magnetic Disturbances. — The con- 

 nection between sunspots and magnetic disturbances having lieen 

 clearly established, it would seem natural to infer from the pre- 

 ceding and other similar indications of the independence of sun- 

 spot and prominence activity that but little connection would be 

 traced between individual prominence displays and terrestrial 

 magnetism. A note by M. H. Wild, presented by M. Mascart, 

 appearing in the Coniptcs reiidns, vol. cii. No. 9, seems, how- 

 ever, to favour the idea of a somewdiat close connection, four 

 remarkable observations of prominence-changes made by M. 



Trouvelot having been found to synchronise fairly closely with 

 magnetic disturbances. An examination of the magnetic 

 traces at Greenwich has, however, shown that in only one 

 case out of the four was there anything like a sharp disturbance, 

 the movements in the other instances being of a very ordinary 

 character. Further, M. Trouvelot has recently published a 

 series of prominence-observations in the Bulletin Astronomique 

 for January, and in no one of these instances was there any- 

 thing like a magnetic disturbance to correspond to the great and 

 remarkable prominence-change M. Trouvelot was observing in 

 the sun. 



Displacement of Lines in Solar Prominences. — The 

 observations of M. Trouvelot above referred to deserve a very 

 careful and detailed examination, as, if confirmed, they will go 

 far to utterly overthrow the views at present held as to the sig- 

 nificance of the displacement of lines in the spectra of sunspots 

 and prominences. M. Trouvelot records displacements so extra- 

 ordinary, that an entire jirominence more than 3' in height was 

 rendered visible when wholly outside the (tangential) slit, which 

 wasnearly closed ! Other similar phenomena are also recorded, 

 only less astonishing. It is of the utiiiost importance that, if 

 other spectroscopists have witnessed similar phenomena, they 

 should not delay to publish their experiences, as it seems im- 

 possible that displacements of so peculiar a character can be due 

 solely to the motion in the line of sight of the gases under 

 examination. In the meantime it would seem more reasonable 

 to suppose that M. Trouvelot had made some extraordinary 

 error in his observations. 



ASTRONOMICAL PHENOMENA FOR THE 



WEEK 1886 MARCH 2%— APRIL 3 



('I7OR the reckoning of time the civil day, commencing at 



^ Cjreenwich mean midnight, counting the hours on to 24, 



is here employed.) 



At Greenwich on March 28 



Sun rises, 5h. 451T1. ; souths, I2h. 5m. 6'6s. ; sets, i8h. 24m. ; 



decl. on meridian, 3° 4' N. : Sidereal Time at Sunset, 



6h. 48m. 



Moon (one day after Last Quarter) rises, 2h. 19m. ; souths, 



6h. 48111. ; sets, iih. 19m. ; decl. on meridian, 17° 54' S. 



Planet Rises Souths Sets Decl on meridian 



Mercury ... 5 53 ... 13 o 



Venus 411 ... 9 30 



Mars 15 16 ... 22 20 



Jupiter 17 27 ... 23 38 



Saturn -9 33 ... 17 45 



20 7 ... 12 13 N. 



14 49 ... S 45 S. 



5 24* ... II 41 N. 



5 49* ... I 23 N. 



I 57* ... 22 49 N. 



March 

 30 ■ 



Indicates thai the setting is that of the folio 

 h. 

 2 ... Mercury stationary. 



Variable-Stars 

 R.A. Decl. 



U Ce])hei o 52-2 ... 81 16 N. ... Mar. 28, 19 14 m 



R Sculptoris ... i 217. ..33 8 S. .., „ 29, M 



S Ursa; Majoris ... 12 39'o ... 61 43 N. ... ,, 30, m 



R Bootis 14 32-2 ... 27 14 N. ... ,, 28, m 



5 Libra; 14 54-9 ... 8 4 S. ... ,, 28, 5 10 ni 



Apr. I, 20 52 HI 



U Coronre 15 I3'6 ... 32 4 N. ... Mar. 30, o 11 m 



W Herculis 16 3r2 ... 37 34 N. ... Apr. 3, m 



U Ophiuchi 17 lO'S ... I 20 N. ... Mar. 29, 5 26 m 



and at intervals of 20 8 

 X Sagittarii 17 40-4 ... 27 47 S. ,., Mar. 31, o o /« 



Apr. 2, 21 30 M 

 W Sagittarii ... 17 57-8 ... 29 35 S. ... ,, 3, 2 20 vi 

 U Sagittarii 18 25-2 ... 19 12 S. ... Mav. 30, 4 50 in 



Apr. 2, 4 50 M 



$ Lyrje 18 45-9 ... is H ^- ■■■ M=i''- 3"' 21 30 m^ 



R Lyrae 18 51-9 ... 43 48 N. ... ,, 28, m 



ij Aquilje 19 467 ... o 7 N. ... Apr. I, 2 20 jl:? 



R Sagittje 20 8-8 ... 16 23 N. ... ,, I, m 



5 Cephei 22 24-9 ... 57 50 N. ... Mar. 28, 4 50 m 



M signifies maximum ; m minimum ; m^ secondary minimum. 



Meteor Showers 



Meteors from the following radiants may be looked for : — 



Near S Ursa; Majoris, R.A. 180°, Decl. 60° N. ; near ;3 Bootis, 



R.A. 223°, Decl. 40" N. ; near 3 Libr£e, R.A. 226°, Decl. 8° S. 



Fireball date, April 2. 



