February 1, 1897.] 



KNOWLEDGE. 



55 



PERIODICAL COMETS DUE IN 1897. 



By W. T. Lynn, B.A., F.E.A.S. 



DR. SPITALEE (now of the Imperial Observatory 

 at Prague) discovered a faint comet at Vienna 

 on the 17th of November, 1890. As it was 

 found to be moving in an elliptic orbit with a 

 period of less than six and a half years, he has 

 calculated that it should return to perihelion on the 

 11th of March in the present year. But it was nearest 

 the earth in September, and as it has not been seen, we 

 must conclude that it is too faint to be visible at this 

 return. 



Two other periodical comets will be due in perihelion 

 during the forthcoming spring ; that of D'Arrest, which 

 was discovered at Leipzig on the 27th of June, 1851, 

 calculated to complete a revolution in six and a half years, 

 and observed at appearances in 1857, 1870, 1877, and 

 in 1890, when it passed its perihelion on the 16th of 

 September ; and that which was first discovered by Tempel 

 Ln November, 1869, but its periodicity was not detected 

 until after its rediscovery by Prof. Swift in October, 1880, 

 in consequence of which it is usually known as Swift's 

 comet. The period of the latter is only about five and a 

 half years ; but as it escaped observation in 1875, when it 

 was not looked for, so also it did in 1884, when it was, 

 though with small hope of seeing it, as it was unfavourably 

 placed. It was, however, well observed at the last return, 

 which took place in 1891 ; the perihelion passage took 

 place on that occasion in the month of November, and 

 another will be due in April or May next. 



[It may not be out of place to add to Mr. Lynn's list of 

 periodical comets expected this year the fact that the comet 

 discovered by Mr. Perrine on December 9 th, 1896, has 

 now been found to be a comet of short period, six and a 

 half years, and therefore, like the above, a member of the 

 " Jupiter family." More interesting still, its elements 

 closely resemble those of the lost comet of Biela in every- 

 thing but the longitude of the perihelion. — E. Walter 



Maunder.] 



♦ 



THE FACE OF THE SKY FOR FEBRUARY. 



By Herbert Sadler, F.R.A.S. 



SPOTS still occasionally appear upon the solar disc. 

 Conveniently observable minima of Algol occur 

 at 9h. 50m. p.m. on the 7th, at 6h. 48m. p.m. on 

 the 10th, and at llh. 42m. p.m. on the 27th. 

 Mercury is a morning star, but owing to his 

 southern declination is not very well situated for observation. 

 He rises on the 1st at 6h. 22m. a.m., with a southern 

 declination of 18" 22' (at noon), and an apparent diameter 

 of 9f . On the 11th he rises at 6h. 11m. a.m., with a 

 southern declination of 19 ' 39', and an apparent diameter 

 of 7i". On the 21st he rises at the same time, with a 

 southern declination of 19 0', and an apparent diameter 

 of 6i." After this he approaches the Sun too closely to be 

 visible. He describes a direct path through Sagittarius into 

 Capricornus, and is at his greatest elongation (26^° W.) 

 on the morning of the 16th. 



Venus is now becoming a very fine object in the evening 

 sky. On the 1st she sets at 9h. 11m. p.m., or nearly four 

 and a half hours after the Sun, with a southern declination 

 of 0^ 15', and an apparent diameter of 21". On the 12th 

 she sets at 9h. 37m. p.m., with a northern declination of 

 5° 20', and an apparent diameter of 28". On the 19th she 

 sets at 9h. 53m. p.m., with a southern declination of 8° 45', 

 and an apparent diameter of 25". On the 28th she sets at 

 lOh. 7m. P.M., with a northern declination of 12 51', and 



During the month she 



an apparent diameter of 28". 

 describes a direct path in Pisces. 



Mars is an evening star, and is still well situated for 

 observation. On the 1st he sets at 4h. 24m. a.m., with a 

 northern declination of 25 J'^, and an apparent diameter of 

 11", the phasis on the following limb amounting to about 

 f". On the 12th he sets at 8h. 58m. a.m., with a northern 

 declination of 25' 23', and an apparent diameter of 9-9". 

 On the 19th he sets at 3h. 41m. a.m., with a northern 

 declination of 25° 31', and an apparent diameter of 9^". 

 On the 28th he sets at 3h. 15m. a.m., with a northern 

 declination of 25° 38', and an apparent diameter of 8V'. 

 During February he pursues a direct path in Taurus. 



Jupiter is an evening star, and is now well situated for 

 observation. He rises on the 1st at 6h. 58m. p.m., with a 

 northern declination of 9° 47', and an apparent equatorial 

 diameter of 44|". On the 12th he rises at 6h. 5m. p.m., 

 with a northern decHnation of 10° 16', and an apparent 

 diameter of 45f' . On the 20th he rises at 5h. 80m. p.m., 

 with a northern declination of 10' 40', and an apparent 

 diameter of 45i". On the 28th he rises at 4h. 50m. p.m., 

 with a northern declination of 11" 4', and an apparent 

 diameter of 45V'. During the month he describes a short 

 retrograde path in Leo. 



Both Saturn and Uranus are, for the purposes of the 

 amateur observer, invisible. 



Neptune is an evening star, setting on the 1st at 8h. 18m., 

 with a northern declination of 21° 28', and an apparent 

 diameter of 2-7". On the 28th he souths at about 

 6h. 30m. P.M. 



There are no very well marked showers of shooting stars 

 in February. 



The Moon Is new at 8h. 13m. p.m. on the 1st ; enters 

 her last quarter at 7h. 25m. p.m. on the 9th ; is full at 

 lOh. 11m. a.m. on the 17th ; and enters her last quarter 

 at 3h. 44m. a.m. on the 24th. 



By C. D. LooooK, B.A.Oxon. 



Communications for this column should be addressed to 

 0. D. LocooK, Burwash, Sussex, and posted on or before 

 the 10th of each month. 



Solutions of January Problems. 



No. 1. 



(W. Clugston.) 



1. B to QR3, and mates next move. 



It will be noticed that the second move is identical in 



every variation. 



No. 2. 

 (J. T. Blakemore.) 

 Key-move. — 1. QxP. 

 If 1. . . . KtoK4, 2. QxPch, etc. 



1. . . . PxR, 2. QxPch, etc. 



1. . . . PtoK7, 2. RxP, etc. 



1. . . . BxKBP, 2. B to Kt3ch, etc. 



1. ... B to K5, 2. Q to Q6 mate. 



1. . . . KtxP, 2. Q tol!5 mate. 



1. . . . Anything else, 2. QxPch, etc. 

 Nearly all our solvers have gone astray over this fine 

 problem. 



Correct Solutions of both problems received from 

 Alpha, E. W. Brook, both of whom, however, overlook the 

 defence, P to K7. 



Of No. 1 only from G. G. Beazley, Rev. F. W. Quilter, 

 D.D., W. H. Stead, J. M'Robert, E. C. Willis, Captain 

 Forde, Sigma. 



