234 



NATURE 



[Jan. 5, I 



The Clinton Catalogue. — The Sidereal Messenger for 

 December announces that the great catalogue of 30,000 stars, 

 upon which Dr. Peters and his assistant, Prof. Borst, have been 

 engaged for several years past, is virtually completed, and ready 

 for the press, and its publication is expected during the present 

 v/inter. In the prosecution of this work Prof. Borst has 

 gathered the stars from the various astronomical publications of 

 the last fifty years, and reduced them to the epoch of the forth- 

 coming catalogue. 



OCCULTATIONS OF STARS BY PLANETS. — Herr A. Berberich 

 calls attention in the Astronomische Nachrichten, No. 2814, to 

 the importance of observations of occultations of stars by the 

 planets, and supplies a list of stars which may possibly be 

 occulted by either Venus, Mars, Jupiter, or Saturn, during 

 the course of the present year. Such observations have been 

 extremely rare, yet they would prove extremely important, for 

 they would throw light on the extent and density of the planetary 

 atmospheres, and would afford a means in the cases of Mars and 

 Venus for the determination of parallax and diameter. Herr 

 Berberich adds that in the case of the three outer planets the 

 occultation of a star by the primary would afford a specially 

 favourable opportunity for the determination of the positions of 

 the satellites, since micrometer measures of their places as 

 referred to the occulted star would be free from many errors to 

 which the direct comparison of the planet and its satellites is 

 exposed. 



The following stars may possibly undergo occultation during 

 the next fortnight : — 



G.M.T. of Con- 

 Planet, junction in R.A. 

 h. m- 

 Jan. 5 

 9 



Star. 



PI - * Max 

 Mag. Ai5 Duration. 



29-2 S.D. -17 No. 4187 97 



1-4 18 4279 9'S 



12 3 41 4 4 3445 9"3 



12 8 32-3 19 4401 9*3 



14 18 40-8 19 4441 9"5 



15 I 31-9 23 4446 9'5 

 17 23 22-5 20 4635 9-3 



The maximum duration is the interval between immersion 

 and emersion for a central occultation. 



-013 

 + I-05 

 -o-i8 



+ 0-84 

 -o*i9 

 + 0-38 

 -0-57 



60 



5-8 

 7-4 

 57 

 5-6 

 5-5 

 5-4 



ASTRONOMICAL PHENOMENA FOR THE 

 WEEK 1888 JANUARY 8-14. 



/■"PJ*OR the reckoning of time the civil day, commencing at 

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

 is here employed.) 



At Greenwich on January 8 

 Sun rises, 8h. 7m. ; souths, I2h. 6m. 49TS. ; sets, i6h. 7m. : 

 right asc. on meridian, I9h. i6"8m. ; decl. 22° 17' S. 



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

 that of the following morning. 



Occultation of Star by the Moon (visible at Greenwich). 



Jan. 



Star. 



Mag. 



Disap. 



h. m. 

 6 18 



Reap. 



h. m. 

 6 46 



Corresponding 

 angles from ver- 

 tex to right for 

 inverted image. 



... 341 298 



Jupiter in conjunction with and 4° 12' south 



of the Moon. 

 Venus in conjunction with and 2° 16' south 



of the Moon. 



Star. 



U Cephei 

 {■ Geminorum 



Variable Stars. 

 R.A. Decl. 



h. m. , / 



o 52*4 ... 81 16 N. 

 6 57-5 ... 20 44 N, 



Jan. 



R Canis Majoris... 7 I4"5 ... 16 12 S. 



U Monocerotis 



S Cancri 



R Leonis 



R Ursae Majoris , 



T Ursse Majoris 



W Virginis ... 



5 Librae 



U Coronae ... 



U Ophiuchi .. 



T Vulpeculae 



Y Cygni 



W Cygni 

 S Cephei 



7 25-5 ... 



8 37-5 •• 



9 4i"5 ••• 

 10 367 ... 



12 313 ... 



13 20-3 ... 



14 55-0 ... 



15 I3'6... 

 17 10-9 ... 



20 467 ... 



9 33 S. ... ,, 



19 26 N. ... ,, 



57 N. ... „ 



22 N. ... ,, 



6 N. ... „ 



48 S. ... „ 



4S. . „ 



3N. ... „ 



20 N. ... ,, 



and at intervals 



27 50 N. ... Jan. 



h. 



10, 22 



9, 3 

 14. 3 



11, 22 

 13, 2 

 II, 



9. 23 



22 tn 

 o m 



o 71/ 



53 '« 



9 w 



ni 



12 m 



M 



M 



12, 



8, 22 



II, 4 



8, o 



8, 4 



of 20 



11, o 



12, I 

 ID, 21 



13, 21 

 14. 



8, 4 

 II, 22 



Near | Virginis. 

 ,, ^ Bootis . 

 ,, )3 Bootis . 



20 47-6 ... 34 14 N, ... ,, 



21 31-8 ... 44 53 N. ... ,, 



22 25-0 ... 57 51 N. ... ,, 



signifies maximum ; ;;/ minimum. 



Meteor- Showers. 

 R.A. Decl. 



174 ... 9 N. ... January 11. 



220 ... 14 N. ... Very swift ; streaks. 



222 ... 42 N. ... Very swift ; streaks. 



DUN^R ON STARS WITH SPECTRA OF 



CLASS II L 1 



I. 



I 



N publishing a few days before his death the last part of his 

 discoveries relating to the spectra of stars of the third class, 

 D'Arrest pronounced the opinion that henceforward there would 

 be nothing essential to add to the knowledge then possessed of 

 the stellar spectra of this class in the northern heavens. When 

 D'Arrest died, 123 well-developed objects of Class lll.a were 

 known, and counting all the objects known, 150 ; the stars 

 known in Class IILi^ were 23. Actually, the well-developed 

 stars of in. a are 214, and if all are reckoned, 475; the stars 

 of 111.(5 are 55 at least. 



The number of objects in Class III. with which we are 

 acquainted has been tripled by recent researches, but, besides, 

 the relation between the numbers of the stars in the two lower 

 classes has been considerably altered, considering that at present 

 there are 8'5 stars III.« instead of 6*5, to i star HI./'. How- 

 ever, we should commit a serious error if we drew the conclusion 

 that in reality the spectra III.^ were not more than nine times 

 rarer than I II. a. On account of the enormous width of the 

 bands, one is able without any difficulty to recognize the 

 nature of a spectrum lll.b in very faint stars, which one is not 

 able to do in III.«, unless in the rare objects of this class in 

 which the bands are more marked and broader than usual. 



I find this opinion confirmed by the fact that the researches 

 of M. Vogel give more than 200 new spectra lll.a, and have 

 scarcely led to an acquaintance with one new spectrum lll.b. It 

 is very probable therefore that we are already acquainted with 

 all these stars to the magnitude of 7 "5 inclusive ; this is rendered 

 still more probable by the following table, which gives the 

 number of the stars III. a and lll.b belonging to different 

 magnitudes : — 



Class lll.a. Class 1 11.^. 



o 

 o 

 o 

 o 



2 

 II 



18 



14 

 10 



24 



' We have already referred generally to M. Duner's important memoir 

 published in the Transactions of the Swedish Academy. We now give a 

 translation of his general conclusions. — Ed. 



