July S, 1880] 



NA TURE 



OUR ASTRONOMICAL COLUMN 

 The Variable Nebula near f Taurl —Though there has 

 been no mention of late of observation of the vicinity of the 

 nebula discovered near (,' Tauri on October 19, 1855, by 

 Chacornac, at Paris, and of which he found not the least trace 

 in November, 1862, it may be nevertheless hoped that attention 

 has been directed to the neighbourhood, even if with negative 

 results. As we do not find a sufficiently detailed account of 

 Chacornac's experiences bearing upon this nebula in our astro- 

 nomical treatises, we may recapitulate them here. 



Chacornac tells us that vxhen constructing, at Mar.-eilles, the 

 chart No. 17 of the Atlas employed in the search for small 

 planets, he registered between December 3, 1853, and February 

 20, 1S54, a great number of stars in this part of the heavens, 

 and amongst others he observed, from January 26 to 31, a star of 

 the eleventh magnitude, the position of which for the beginning 

 of 1852 was in K.A. 5h. 28m. 35'6s., and Decl. + 21° 7' 18". 

 At that time and later he did not perceive any nebulo.-ity about 

 it ; at the Obser\alory of Paris on September I and December 

 17, 1854, with a refractor of ten inches aperture he did not 

 detect any such appearance. On October 19, 1S55, in verifying 

 ihe chart of this region, he remarked a faint nebula about the 

 ^tar and delineated it upon the map. He was then, as he says, 

 far from thinking that objects generally considered to be masses 

 of small stars could vary in bri.jhtness Id^e the isolated variables, 

 and attributed the degree of visibility to the greater or less 

 degree of Iransparericy of our atmosphere. Eut under the idea 

 that the nebulosity might really be a distant comet, he endea- 

 voured to repeat his observation on following nights, thou.jh 

 from clouds and moonlight it was not till November 10 that he 

 could satisfy himself that the object was precisely as he saw it 

 on October 19, having changed neither in position, extent, nor 

 form. It brightness was particularly remarked on January 27, 

 1856, when it is recorded: "Elle oifre I'apparence d'un nuage 

 ti-ansparent qui semble rtflecter la lumiere de I'c'toile f Taureau, 

 et son aspect tout different de celui dela nebuleuse 357 (Herschel 

 II. ) ne fait naitre aucune idee de points stellaires visibles sur toute 

 I'etendu de sa sur.''ace. Cette nebuleuse dTIerschel se presente 

 en effet coaime un amas d'etoiles qui s'aper9oivent distinctement 

 separees les uues des autres meme avec un faible grossissement, 

 tandis que le s&uvenir que je garde de la nebuleuse variable ne 

 I'a fait comparer a un leger cirro- stratus sXi\i de bandes paralleles : 

 cette desciiption est, du reste, en toute conforme au dessin de la 

 carte." 



From the end of January, 1856, until November, 1S62, the 

 dates of comparisons of this chart « ith the sky were not recorded, 

 but on the 20th of the latter month Chacornac failed to see the 

 least trace of the Nebula, though the star of the eleventh magni- 

 tude, upon whicli it was formerly projected, remained of pre- 

 cisely the same brightness. On frequent occasions subsequeatly, 

 before notifying his discovery in April, 1S63, he could see no 

 vestige of nebulosity with the instruments at the Observatory of 

 Paris. With regard to the appearance of the nebula Chacornac 

 remarks : " Elle offrait une forme presque rectangulaire, dont le 

 plus grand cote mesurait un arc de 3 minutes et demie, et le plus 

 jietit 2 minutes et demie." The eleventh magnitude, according 

 to his position, precedes f Tauri, 12 •6s., and is 4' 26" north of 

 that star; it appears to be No. 907 of the zone + 21° in the 

 Diin!imitstii uul;, where it is rated 9"4m , the scale of magni- 

 tudes in that catalogue not being identical with Chacornac's. 



In the same neighbourhood is a variable star notified by Prof. 

 Julius Schmidt, which follows the bright nebula h 357, about 

 23"8s., with 4''2 le-s declination. It is No. S94, zane -1- 21' in 

 the Durchmu^ilaiiiig, and there called 9'5m. According to 

 Schmidt's observations it was S'9 on February 4, 1S61, Ii'i2 on 

 March 21, 1S62, 9 on January 9, 1S64, and 10 at the end of the 

 same year; he found its place for l86fO in R.A. 5h. 26m. 33'7s., 

 and Decl. -f 21° 50' 47" ; a twelfth magnitude follows it 37s., 

 about i' iS" to the south. 



The Great Comet of 1S80. — Dr. B. A. Gould has calcu- 

 lated a third parabolic orbit for the southern comet which he 

 finds to represent his observations very closely ; the elemeuts 

 are ; — 

 rerihelion passage, 18S0, January 27'4ll7o Washington M.T. 



Longitude of perihelion ... 280 11 10) Mean equinox, 

 ,, ascending node 7 7 38 j 18S0 o 



Inclination 35 12 27 



Log. of perihelion distance.. 7726S724 

 Mali, n— rer.-r.".de. 



He has also computed an ephemeris for February, from whicli 

 we extract positions and distances for the period during which 

 the tail was visible. 



At Washington nuan noon. 



Right As 



DecUnatic 



Log. distance from the 

 n. m. s. , , Earth. Sun. 



Feb. 2 ... 21 47 38 ... -28 57-6 ... 9-86856 ... 9-53319 



3 -. 22 3 4 ... 30 8-8 ... 9-85728 



4 .. 22 19 12 ... 31 10-8 .. 9-84799 ... 962292 



5 ... 22 35 54 ... 32 3-1 ... 9-84064 



6 ... 22 53 I ... 32 44-9 ... 9-83521 ... 9-69139 



7 .-- 23 10 24 ... 33 15-8 ... 9-83167 



8 ... 23 27 52 ... 33 35-8 ... 9 82994 - 974677 



9 -•■ 23 45 '3 ■-■ 33 44-9 ■-- 9-82997 



10 ... o 2 17 ... 33 43-8 ... 9-83165 ... 9-79326 



11 ... o iS 55 ... II 33-1 ... 9-83487 



12 ... o 34 58 ... 33 13-7 ... 9-83949 -. 9-83333 



13 ... o 50 20 ... 32 47-0 ... 9-84538 



14 ... I 4 57 •■• -32 14-0 -•- 9-85237 •-- 9"S6S53 

 This gives the least distance of the comet from the earth o 6757 

 of the earth's mean distance from the sun at about 6h. a.m. 

 Greenwich time on Febru.ry 9. 



The Diameter of -Vesta. — Prof. Tacchini has taken 

 advantage of the recent favourable opposition of this planet 

 to mea.sure the apparent diameter, which vvith a power of l,oco 

 on his refractor he found to be, on June 9, i"-7o6. This value 

 reduced to the mean distance is about double that resulting from 

 Secchi's observation at the opposition of 1855, when he judged 

 the apparent diameter to be a little less than that of the first 

 satellite of Jupiter, or about o"-8, but " molto piii debole di 

 luce, e di colore ranciato carico." For distance unity, Tacchini's 

 measure gives l"-96, and Secchi's estimate i"-oi. Probably we 

 may hear of other measures of Vesta at the opposition of the 

 present year, made with large instruments. 



GEOGRAPHICAL NOTES 

 The collections m natural history and ethnography brought 

 home from the coasts of Siberia and Eastern Asia by the Vega 

 are to be exhibited in the old hall of the Royal Library at the 

 Palace, Stockholm. The exhibition was opened yesterday, and 

 Baron Nordenskjold invites naturalists and geographers to visit 

 the collection. 



At the German Athenceum last week the Chevalier Ernst von 

 Hes e Wartegg gave a lecture on his recent travels in North 

 Africa, comprising chiefly the southern parts of Algiers and 

 Tunis and the rarely-visited frontier regions between these two 

 countries. Herr von Wartegg's 'principal aim was the thorough 

 revision and completion of the very defective Tunisian map of 

 the French General Staff, edited in 185S, and the investigation of 

 the Schott region in Southern Tunis, adjoining the Lesser Syrtes. 

 The first object was, according to the lecturer, satisfactorily 

 completed by the substantial aid of the Tunisian Government 

 and the foreign consular body at Tunis. To point out a few in- 

 stances of the deficiency of the French maps, Herr von Wartegg 

 mentioned the large river Kassab, a tributary of the Medjerdah, 

 which in the map empties into the Mediterranean about 200 

 kilometres from its actual mouth. Large lakes are entirely 

 omitted, and cities invented which do not exist. The main fault 

 of the map is the erroi eous spelling of the topography, Frenchi- 

 fying and mutilating nearly every name. For instance, the Arab 

 word Sandjak has been turned into "Saint Jacques," &c. Re- 

 garding the well kuo.vn project of Capt. Roudaire and M. de 

 Lessep.s, the lecturer states that neither the geological formation 

 nor any other sign indicates the former connection between the 

 so-called "submarine basin" in Southern Tunis and Algiers, 

 and he believes, contrary to the sanguine dreams of Capt. Rou- 

 daire, that it never was connected with the Mediterranean. Ac- 

 cording to his observations the submarine basin in the interior 

 approachts the coast only at a distance of about seventy miles, 

 and the canal to be constructed across the isthmus would have to 

 be therefore of that length. The cost of such a work, rivalling 

 the Suez Canal in magnitude, would never be in proportion to 

 the benefit derived, which latter is entirely doubtful. No 

 thorough investigation of the region was ever made, and its re- 

 sults would never be certain, as the constant vibration of the air 

 in this hot climate and the deceptions caused by frequent fata 

 morganas render scientific measurements very problematic. If 



