522 



NAT J RE 



[April 3, 1890 



(6) This variable will reach a maximum about April 9. Its 

 j-ieriod is about 360 days, and the rnagniludes at maximum and 

 qninimucn are 6i-7'8 and I i'9-i2'5 respectively (Gore). Tne 

 spectrum is a very fine one of Group II., and the great range of 

 variation makes it extremely probably that bright lines will 

 appear at maximum or soon after, as already observed by Mr. 

 Espin in variables with similar spectra. Variations in the 

 intensities of the bright carbon flutings should also be noted. 



A. Fowler. 



The Great Comet of 1882. — The Bulletin Astronomiijuc 

 for February 1890 reproduces with some additions a paper pre- 

 sented t;y M. F. Tisserand to the Academy of Sciences on 

 February 3. It will be remembered that the segmentation of 

 \.\t nucleus of this comet was observed on September 30, 1882 

 — that is, thirteen days after perihelion passage, and that Mr. 

 Common in January 1883 saw five nuclei in a line. From an 

 elaborate investigation into the conditions necessary for the 

 development of these secondary nuclei, M. Tisserand concludes 

 that the cause existed in the comet itself, and was not the result 

 ■of external influence. The minimum relative variation required 

 for the dis iggregation of the nucleus is ikftt^o » of 'he perihelion 

 velocity. And it is suggested that this variation may be pro- 

 duced by interior actions, collisions, mutual attractions, ex- 

 plosions, because of an excessive increase of temperature or the 

 .rotation of the head. 



Melbourne Star Catalogue.— In 1874 the First Mel- 

 I'ourne General Catalogue of 1227 stars for the epoch 1870 was 

 issued. The Second General Catalogue has just been received, 

 and contains 121 1 stars for the epoch 1880, deduced from 

 observations made at the Melbourne Observatory under the 

 direction of Mr. Ellery from i87ro to 1884-7. 1"he separate 

 results and the details of the observation^ from which this Cata- 

 Jogue has been compiled are contained in vols, v., vi., and vii., 

 •■(if the Melbourne Observations, and in the present Catalogue 

 •explanations are given of the processes used in forming the stars' 

 jjlaces and the corrections applied. The whole of the observa- 

 « ions were reduced and prepared for publication by Mr. E. J. 

 AVhite, the First Assistant Astronomer. 



Comet a 1890. — The first comet of this year was dis- 

 <overed just before sunrise on March 21 by Mr. Brooks, at 

 "Cambridge, U.S. Its exact place was found to be — 



The daily movement in right ascension is -f 163., and in 

 <leclination + 25'. 



Discovery of Asteroids.— On March 20, Dr. P.ilisa, at 

 Vienna, discovered another , minor planet, and the telegram 

 announcing his discovery was received at the AstronjiniscJtc 

 Nachrichten office at midday on March 21. This c )met is of 

 interest, for, from its rapid movement in R.A. - 25', in N. P. D. 

 + 10', it appears to be near to the earth. 



M. Charlois, of Nice Observatory, discovered a minor planet 

 -on March 10, and re-observed it on March 2x This brings the 

 number of asteroids up to 290. 



The asteroid (^ discovered by Prof Luthur on February 

 24 has received the name of Glauke. 



Solar Activity in 1889.— The record of the past year aS 

 <o .solar phenomena presents several noteworthy features, (i) 

 The number of days on which the sun appeared to be free from 

 •<'ither spots or faculae ; the days without spots being 211 as com- 

 ij.ared with 158 in 1888 ; and the days when neither spots nor 

 ^iculoe were seen being more than twice as numerous last year 

 iis in the year previous. (2) The distinct but temporary revival 

 of spat activity during the months of June, July, August, and 

 September. (3) The appearance of spots in high latitudes ; and 

 listly, the remarkable falling off in chromospheric phenomena, 

 j)articularly during the last months of the year. It is, therefore, 

 >till difficult to be certain whether we have yet r.^ached the actual 

 minimum or no ; the revival of the spots during last summer, 

 ■connected as it was with so remarkable an increase in their 

 mean distance from the equator, seemed to point to theminimun 

 iiiaving been passed ; but the almost perfect season of quiet which 

 iollowed it, together with the decrease in the number and size of 

 i4he prominences, favour the opposite concKisi m. The mean 

 <laily spotted area for 1889 was less than that for 1888, bat only 

 4)y about one-seventh. 



The three most remarkable groups of 1889 were those first 

 seen on June 16, June 29, and August 2 respectively. The first- 

 named was the largest group of the year ; it formed and dis- 

 appeared on the further side of the sun, and was seen during 

 three rotations. The third was also seen during three rotations, 

 but formed and died out in the visible hemisphere. It was the 

 second group as to dimensions, and lay in S. lat. 20", whilst the 

 spot of June 16 was in S. lat. 6°. The spot of June 29 was only 

 a very small one, and lasted but a couple of days, but was 

 noticeable from its high latif,ude, 40" S. A fourth group, that 

 first seen on August 9, though not attaining so large a mean 

 area as the spot of June 16, exceeded it on one particular day, 

 August 15. 



The following table gives the monthly numbers for spots and 

 faculae as sui^plied by Prof. Tacchini in the Comptes rendiis, vol. 

 cviii. No. 2[, vol. cix. No. 4, and vol. ex. No. 5, and may l)e 



The table shows that as in 1888 the faculte did not vary quite 

 in accordance with the spots, September and December being 

 heavy months for the former, their relative area then exceeding 

 that for any month since July 1886. The prominences on the 

 other hand showed a very marked falling off towards the end of 

 the year ; February and March, light months for spots and 

 facula-, being much the most prolific as to the flames. The 

 following are the mean numbers for the prominences resulting 

 from Prof. Tacchini's monthly reports. It must be borne in 

 mind that the difference in the atmospheric conditions of Eng- 

 land and Italy renders it impossible to compare Prof. Tacchini's 

 results with those formerly given by the late Rev. S. J. Perry, 

 and which have been incorporated in former annual summaries 

 in Nature. 



Prominences. 



iJays of 

 observa'.ion. 



Mean 



daily 



number. 



8-26 



7 94 

 3-20 



Moan 

 heiiiht. 



Wolf's relative 

 numbers (Zurich). 



12'0 



1887 ... 214 ... 8-26 ... 45-2 



1888 ... 227 ... 7 94 ... 45-9 



1889 ... 247 ... 3-20 ... T,^-j 



The variations in the magnetic elements accor 

 more general features, though not in details, with 

 sunspots, as the folio win.; table given by Dr. R. 

 Comptes rcndus, vol. cc. No. 3, sufficiently shows : 



Variation 

 declinati 

 r 



175 ■• 



399 •• 



6-17 .. 



885 .. 



8ig .. 



8-86 .. 



825 .. 



8-99 .. 



684 .. 



610 .. 



2-55 •• 

 I '96 .. 



6 04 . . 



Mean 

 extent. 



17 



I '5 



January 

 February .. 

 March 

 April 



May 



]une 



July 



August ... 



.September 



October 



November 



December 



Mean .. 



I 'o 



7 '9 

 6-3 



4"9 

 24 

 7-0 

 80 

 20 '6 

 6-3 



O'O 

 CO 



57 

 5-8 



-f 0-9 



■+- CO 



-f 10 



- 8-4 



n- 0-5 



+ 6-1 



-f 18 7 



- 15 



- 20 



- 129 



-■4-2 



- o-y 



ded in their 

 those of the 

 Wolf in the 



m magnetic 

 jn (Milan). 



. -1-28 

 + 097 



• - o 94 



. +0-58 

 . -0"29 



-0-41 

 -0-32 



. -018 

 ■ -047 



- O 22 



• +0-37 

 -f-0"20 



o'i7 



Dr. Wolfs formula for Milan, v = 5' 62 4- 0-045 ''» ^'^^ 

 r= 5'8, would give v = 5' '88, a much closer accord than for 

 the two preceding years. 



