Dec. 5, 1889] 



NATURE 



115 



(3) This is classed with stars of the solar type by Gothard, 

 but there is not sufficient detail in his description of the spectrum 

 to enable us to say whether it be Group III. or V. Further 

 observations with special reference to this point are therefore 

 required (for criteria, see p. 20). Gothard's statement as to the 

 colour of the star should be checked, as most of the stars of 

 Groups III. and V. are yellowish. The stars which are not far 

 removed from Group IV., on either side, are the whitest. 



(4) This is a star of Group IV., and the usual observations 

 are suggested. 



(5) This is a ver}- fine example of the stars of Group VI., 

 showmg the subsidiary bands 4 and 5. The band 6 (\ 564) 

 appears to be most subject to variation in the different stars of 

 the group as described by Duner, in some cases being wide and 

 pale, and in others wide and dark. As this may subsequently 

 form the basis of a temperature classification, the character of 

 the band in the star under consideration should be carefully 

 noted. The presence or absence of lines in the spectrum should 

 also be recorded. [Duner's notation for the bands in the spec- 

 trum of stars of Group VI. is as follows :—(i) 656, (2) 621, 

 (3) 604-8, (4) 589-8, (5) 576-0, (6) 563-3, (7) 551, (8) 528-3, 

 (9) 516-3, (10) 472-7. (6), (9), and (10) are the dark flutings of 

 carbon.] 



(6) The period of this variable is given by Gore as 210 days, 

 and the magnitudes at maximum and minimum as 7-7-9-2 and 

 12-5 respectively. The spectrum has not yet been recorded. The 

 maximum will occur on December 15. 



(7) This variable has a period of 288-1 days, the next maxi- 

 mum occurring on December 14. The magnitude at maximum 

 is given by Gore as 81-8-7, and that at minimum as < 13. It 

 is still doubtful whether the star belongs to Group II. or to 

 Group VI., and the approaching maximum may afford an 

 opportunity of settling the question. A. Fowler. 



Sun-spot of June, July, and August, 1889.— The 

 Memoir of the Societa degli Spettroscopisti Italian! for October 

 contains a series of observations by Prof. Ricco of this spot. 

 The latitude of the spot from its appearance on June 16 and 

 during the first semi-rotation, varied between the limits -5°-9 

 and - 7° -5. At the second appearance, the variation was 

 between - 7°-5 and - 10° "8, whilst at the third appearance, in 

 August, the limiting latitudes were - 8^-5 and - 10°. 



The group of spots that appeared on June 30 was found to 

 have a latitude as high as - 41°. The following day, however, 

 the latitude was found to be - 40^°, and on July 2 the group 

 disappeared. 



Prof Sporer, in a communication to Prof. Ricco, notes that 

 the following bright lines were measured at Potsdam on June 28 

 in a prominence that appeared as the above large spot was dis- 

 appearing over the sun's edge. 



AVave-length. 

 6726 

 671-6 



C 

 649-2 

 646 2 



Di 

 D., 



D.: 



Origin. 

 Calcium 

 C alcium 

 Hydrogen 

 Calcium 

 Calcium 

 Sodium 

 Sodium 



Photographic Star Spectra.— As a portion of the Henry 

 Draper memorial, the spectra of stars are being photographed 

 at Chosica in Peru. Of the photographs that have been re- 

 ceived at Harvard College, Prof. Pickering notes {Js/r. Nachr., 

 No. 2934) several have similar spectra to the "bright line" 

 stars in Cygnus. The hydrogen line F is bright in Q Muscce, 

 the same as in 7 Cassiopeia?, and the presence of bright hydrogen 

 lines in r/ Argus and R Hydrse is also confirmed by the photo- 

 graphs. 



Numerous photographs have been taken at Harvard College 

 of ihe spectra of the stars in the Pleiades, and an examination of 

 them shows that ths hydrogen line F in the spectrum of Pleione 

 D.M. -V 23° 558, consists of a narrow bright line superposed on 

 a broader dark line. The other hydrogen lines, especially that 

 near G, show some indications of a similar effect. 



With respect to this. Prof. Pickering observes that an in- 

 teresting analogy between the Pleiades and Q Orioiiis appears 

 in the fact that in bjth cases extensive nebulosities surround 

 stars with bright lines in their spectra. 



Comet Brooks {d 1889, July 6).— The following elements 

 and ephcmeris have been computed by Dr. Knopf from observa- 

 tions made at Mount Hamilton, July 8 ; Dresden, August 25;. 

 and Vienna, October 24 :^ — 



t = September 29-7436 Berlin Mean Time. 



iw- 343 1856-5 ) 



fi = 17 58 29-6 V Mean Eq. 1889-0. 

 ' = 63 59-6 ) 

 <) = 28 4 13-3 

 /u = 5oi"-8i56 

 U = 7-071 years. 



Efhemeris for Berlin Midnight. 



Dec, 



Mr. Chandler notes {Astr. J our. No. 204) that the result of an 

 .inquiry into the corrected elements of this comet is extremely 

 interesting. The descending node of the comet's orbit upon 

 that of Jupiter lies at i85°-5 long., Jupiter's aphelion at 191% 

 and the comet's aphelion at i83\ The aphelion distances are 

 5-4541 and 5-3992 respectively, the mutual inclination of the 

 orbits is 3°, and the orbital velocities nearly the same ; so that 

 when both bodies happen to be near this region they will 

 rtmain together many months. . 



Comet Swift (/1889, November 17).— The following ele- 

 mtnis and ephtmeris are given by Dn Zelbr in Circular- 

 No. 69, issued by the Vienna Academy of Sciences, November 

 25, 1889, and have been computed from observations made at 

 Rochester, November 17 ; Vienna and Palermo, November 20^ 

 and at Vienna, November 22 :— 



T = 1889 December 10-5665 Berlin Mean Time. 



fi = 309 51 12 ) 

 w = 109 24 70 > Mean Eq. 1889-0, 



* = 7 14 I ) 

 log q = 0-07554, 



A\ cos j8 = + 132" ... Aj8 = - 14". 



Ephcmeris for Berlin midnight. 



R.A. 



Decl. 



Log A. 



Log r. ■ Bright- 

 1. m. s. ^ , ne.ss. 



Dec. 7 ... 23 41 56 ... -m8 32-4 ... 9-6509 ... 00759 ... 1-29 

 II ... 23 58 44 ... 20 2-7 ... 96457 ... 0075b ... 1-32 

 The brightness at discovery has been taken as unity. 



S Cassiopei.*:. — The Rev. T. E. Espin, examining the spec- 

 trum of this star on November 27, found that it resembled in 

 appearance that of R Andromedse, the bright F line blazing out 

 upon the background of the continuous ^pectrum, and being 

 plainly visible even with the least dispersion used. The star is 

 not included by Duner in his classical work, " Les Etoiles a 

 Spectres de la Troisieme Classe," but its general spectrum is 

 apparently of that type — Group II. oi Mr. Lockyer's classifica- 

 tion. Mr. Espin adds that ''the yellow is brilliant, suggesting 

 (bright) lines, but the star is at present too faint to be sure." 



The star is a variable of very long period, 607-5 days; the 

 next expected maximum falls on D cember 26, so that it may 

 show some lurther ar.d interesting developments during the next 

 three weeks. Chandler, however, records his suspicion that the 

 period is shortening, so that the actual maximum may be very 

 close at hand, T he maximum brightness varies frjm 6 7 mag. 

 to 8-6. Mr, Espin estimated it as 78 on the night of 

 observation. Place for iJ:'9o: R.A. ih. iim. 34s,; Decl. 

 72° i'-9 N. 



