July 1, 1896.] 



KNOWLEDGE. 



167 



greatest western elongation (21^°) on the 4th, and in 

 superior conjunction with the Sun on the 31st. 



Venus is in superior conjunction with the Sun on the 

 9th, and Mars is, for the observer's purposes, invisible. 



•Jupiter is now too near the Sun for satisfactory obser- 

 vation. 



Saturn is an evening star, setting on the 1st at Ih. 

 A.M., with a southern declination of 13^^'^, and an apparent 

 equatorial diameter of 16j" (the major axis of the ring 

 system being 41 ' in diameter, and the minor Hf/'). On 

 the 9th he sets at Oh. 28m. a.m., with a southern declination 

 of 13° 20', and an apparent equatorial diameter of 16j^". 

 On the 18th he sets at llh. 49m. p.m., with a southern 

 declination of 13' 22', and an apparent equatorial diameter 

 of 161" (the major axis of the ring system being 40r" in 

 diameter, and the minor 14"). On the 22nd he sets at 

 llh. 34m. P.M., with a southern declination of 13" 23', and 

 an apparent equatorial diameter of 10}". On the 29th he 

 sets at llh. 6m. p.m., with a southern declination of 

 13° 27', and an apparent equatorial diameter of 18|" (the 

 major axis of the ring system being 39 V' in diameter, and 

 the minor 13|"). 



lapetus is in inferior conjunction on the 1st, and at his 

 greatest western elongation at 9h. 30m. p.m. on the 21st. 

 He is almost stationary in Libra throughout the month. 



Uranus is an evening star, but owing to his great southern 

 declination is not well situated for observation. On the 

 1st he rises at 4h. 2m. p.m., with a southern declination of 

 17° 41', and an apparent diameter of 3-8". On the 30th 

 he sets at llh. 2m. p.m., with a southern declination of 

 17° 37'. He is almost stationary in Libra throughout the 

 month. 



Neptime does not rise till after midnight at the end of 

 the month. 



Shooting stars are fairly numerous in July, but twilight 

 interferes with observation. There is a well-marked shower 

 near J Aquarii towards the end of the month, the maximum 

 being on the 28th. The radiant point is in E.A. 22h. 40m., 

 south declination 13°. 



The Moon enters her last quarter at Ih. 23m. a.m. on 

 the 3rd ; is new at 7h. 85m. p.m. on the 10th ; enters her 

 first quarter at 4h. 4m. p.m. on the 17th ; and is full at 

 5h. 45m. P.M. on the 24th. She is in apogee at 3h. a.m. 

 on the 3rd (distance from the Earth, 251,150 miles) ; in 

 perigee at 6h. p.m. on the 15th (distance from the Earth, 

 229,200 miles) ; and in apogee at lOh. p.m. on the 30th 

 (distance from the Earth, 251,280 miles). 



(ITi^css Column. 



By C. D. LocooK, B.A.Oson. 



Communications for this column should be addressed to 

 C. D. LococK, Burwash, Sussex, and posted on or before 

 the 10th of each month. 



Solution of June Problem. 



(A. G. Fellows.) 



1. Kt to B6, and mates next move. 



Correct Solutions received from Alpha, 3. M. K. Lupton, 

 G. A. F. (Brentwoocli, Arthur S. Coulter, A. C. Challenger, 

 W. Willby, W. Y. Popham, H. H. Quilter, H. S. Brandreth, 

 and .1. T. W. Claridge. 



Correct Solutions of May Problems, received too late for 

 acknowledgment last month, from J. M. K. Lupton and 

 E. W. Brook. 



F. TI'</,/(.— 1. Kt to K4, KtxKt, 2. P to B4 mate, and 

 other variations ; 2. Kt to B6 mate is threatened. 



G. G. Bctidey. — If 1. Kt to Q2, QxB, and there is no 

 mate. 



//. Le Jeune. — Is Kt to B5 a misprint for Kt to B6 ? 



A. C. Challenger. — Many thanks. Your compositions are 

 always welcome. 



TI". ,7. Aslidoiiii. — Thanks for your interestu3g communi- 

 cation printed below. 



PKOBLEM. 

 By A. C. Challenger. 



BUCE (6). 



White (7). 



White compels Black to mate in two moves. 



Mr. W. J. Ashdown has sent the following interesting 

 communication on 



THE EIGHT QUEENS PEOBLEM. 



The Queens Problem on a board of sixteen squares has 

 two solutions, namely (using the German notation i, 

 A2, B4, CI, D3, and A3, Bl, C4, D2. Let diagrams of 

 these two positions be placed one overlapping the other to 

 the extent of six squares — that is, with the top left-hand 

 square of the A3 diagram resting on B2 square of the A2 

 diagram, being a Knight's move downwards. The three 

 Queens must be removed where overlapping occurs, and 

 this is a rule to be observed throughout. 



The position now obtained may be placed on an extended 

 board, the Queens occupying squares B6, Cs, D3, E7, F4, 

 and within a rectangle of thirty squares. This rectangle 

 with its five Queens may be called the " initial position," 

 as all the solutions of the Eight Queens Problem are 

 derived from it. Let the board be extended indefinitely 

 upwards and to the right, and a second " initial position " 

 placed upon it, with the corners of the rectangle resting on 

 squares FIO, F5, JIO, -15, being two Knights' moves to 

 the right. The two rectangles will then overlap four 

 squares, and the Queen thereon must be removed. The 

 four added Queens are at GIO, H.5, 19, ,T(i. This may be 

 called the " doubled position." 



The Queen's stride being limited to seven squares on 

 the ordinary board, the eighth square in any direction is 

 " out of range,'' and additio!;al Queens can, therefore, be 

 placed at .\1, Dll, G2. This at once gives seven solutions 

 of the problem. Thus, the sixty-four squares, from B9, B2, 

 to 19. 12, contain the solution a, and the others are : — 



Sixty -four scjuares from .\8 to 111 contain solution /3. 



C9 to .12 „ y. 



BIO to 13 „ S. 



ClltoJ4 „ ?. 



Bll to 14 „ .. 



„ „ CIO to J3 „ X. 



Any arrangement whatever of Queens, where all are 



