98 



KNOWLEDGE 



[May 2, 1892. 



The other most noteworthy Hot Springs area of the 

 Yellowstone Park is called the "Geyser Basins of the Fire 

 Hole Eiver," consisting of the Lower Basin and the Upper 

 Basin, altogether about 76 square miles. 



The Lower Basin contains thousands of springs of 

 various temperatures, including some gigantic geysers of 

 which the "Fountain" and the "Architectural" geysers 

 are the best known. There are also " Mud Puffs," or 

 centres of boiling mud. The Upper Basin has geysers 

 of still greater importance and becoming famous under 

 the names of " Old Faithful," " The Giant," " The 

 Giantess," " The Grand." ■' The Castle." "The Beehive," 

 .to. All these, like the Geysers of Iceland, deposit 

 silicious sinter or geyserite, of which Dr. Hayden's analysis 

 is : — 



Water ... ... 13-42 per cent. 



Silica 70-80 



Alumina ... !)-4(i 



Lime ., 1-80 



L'on, magnesia, and soda traces 



101-06 



Although the Yellowstone Valley has long ago ceased 

 to be the scene of volcanic activity, great subterranean 

 heat still lingers beneath its mountains, cauons and lakes, 

 and now presents to the admiration of mankind phenomena 

 as beautiful as they are wonderful. 



THE FACE OF THE SKY FOR MAY. 



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



SMALL groups of spots and facula^ continue to appear 

 on the solar surface. The following are con- 

 veniently observable times of the minima of some 

 Algol-type variables {cf. " Face of the Sky " for 

 April). S Cancri.— May 11th, 9h. 32m. p.m. ; May 

 30th, 8h. 48m. p.m. 8 Libra;.— May 4th, 8h. 28m. p.m.; 

 May nth, 8h. 3m. p.m. U Corona?.— May 13th, lOh. 49m. 

 P.M. ; May 20th, 8h. 31m. p.m. 



Mercury is technically a morning star throughout May, 

 but is practically invisible, as on the first day of the month 

 he only rises 24 minutes before the Sun, and on the last 

 day of May he rises three-quarters of an hour before the 

 Sun. Under these circumstances an ephemeris of the 

 planet would be useless. He is at his greatest western 

 elongation (25^°) on the 17th. 



Venus is a superb object in the evening sky, and is 

 \'isible to the naked eye at noonday when her position is 

 accurately known. She sets on the 1st at llh. 49m. p.m., 

 with a northern declination of 26° 49', and an apparent 

 diameter of 23", just one half of the disc being illuminated. 

 On the 15th she sets at llh. 50m. p.ji., with a northern 

 declination of 26° 30', and an apparent diameter of 28", 

 jij^ths of the disc being illuminated. On the 80th she 

 sets at llh. 21m. p.m., with a northern declination of 

 24° 35', and an apparent diameter of 855", just three- 

 tenths of the disc being illuminated. During the month 

 she pursues a direct path through Gemini, without 

 approaching any conspicuous star very closely. At about 

 lOh. 20m. P.M. on the 3rd a 9th magnitude star will 

 be just north of the planet, and at lOh. 30m. p.m. 

 on the 13th a 9| magnitude star will be very closely 

 north of Venus, while at lOh. lOm. p.m. on the 21st 

 a 9J magnitude star will be immediately south of the 

 planet. 



Mars does not rise till after midnight on the last day of 



the month, and .Jupiter is, for the observer's purposes, 

 invisible. 



Saturn is still well situated for observation. He rises 

 on the 1st at 2h. 34m. p.m., with a northern declination 

 of 4° 43', and an apparent equatorial diameter of 

 18-5" (the major axis of the ring system being 42-8" 

 in diameter, and the minor 0-4"). On the 31st he rises 

 at Oh. 82m. p.m., with a northern decUnation of 4° 48', and 

 an apparent equatorial diameter of 17f" (the major axis 

 of the ring system being 40-8" in diameter, and the minor 

 [ 0-3"). The ring system is therefore invisible in small 

 ! telescopes. The following phenomena of the satellites may 

 be observed (the times are given to the nearest quarter of 

 an hour). May 1st, Ijh. a.m., Tethys, eclipse reappear- 

 ance ; May 2nd, lOih. p.m., Tethys, eclipse reappearance; 

 May 4th, 8 p.m., Tethys, eclipse reappearance ; May 9th, 

 8|h. P.M., Dione, eclipse reappearance ; May 18th, Hi. a.m., 

 Tethys, eclipse reappearance ; Ifh. a.m., Dione, eclipse 

 reappearance ; May 19th, 10|h. p.m., Tethys, eclipse 

 reappearance. lapetus is at his greatest western elongation 

 on the morning of May 27th. On the 9th at about llh. 

 P.M. a 9-^ magnitude star will be about f south of the 

 planet. During May Saturn describes a very short 

 retrograde path through part of Virgo, without approaching 

 any naked-eye star. 



Uranus is well situated for observation, rising on the 1st 

 at 6h. 25m. p.m., with a southern declination of 12° 17', 

 and an apparent diameter of 8-8". On the 31st he rises 

 at 4h. 20m. p.m., with a southern declination of 11° 54'. 

 During the month he describes a retrograde path to the 

 N.W. of A Virginis. A map of the path of Uranus is 

 given in the ]ui;ili«h Mcchanicior Yehmary 12th. Neptune 

 is in conjunction with the Sun on the 29th. 



There are no very well marked showers of shooting 

 stars in May. 



The Moon enters her first quarter at 7h. 12m. p.m. on 

 the 3rd ; is full at lOh. 59m. p.m. on the 11th ; enters her 

 last quarter at 2h. 58m. p.m. on the 19th ; and is new at 

 5h. 49m. A.M. on the 26th. She is in apogee at 5-3h. 

 a.m. on the 9th (distance from the earth 252,310 miles) ; 

 and in perigee at 4-Oh. p.m. on the 24th (distance from the 

 earth 224,215 miles). Her greatest western librations 

 occur at Oh. 54m. p.m. on the 2nd, and at 5h. 30m. p.m. 

 on the 30th ; and her greatest eastern at 5h. 35m. a.m. on 

 the 18th. There will be an eclipse of the Moon on May 

 nth, tbe first contact with the penumbra taking place at 

 7h. 55-9m. p.m. ; the first contact with the shadow (at an 

 angle of 82 from the most northern portion of the Moon's 

 limb towards the east, for tlireit image) ; the last contact 

 with the shadow at Oh. 36-6m. a.m. on the 12th (at an angle 

 of 41° from the most northern portion of the Moon's limb 

 towards the west, for iliirct image) ; and the last contact 

 with the penumbi-a at Ih. 5()-pm. a.m. on the 12th. The 

 middle of the eclipse occurs at lOh. 53-4m. p.m. on the 

 nth, Jyij|-\fths of the lunar disc being obscured. 



Cljrss Column. 



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



All communications for this column should be addressed 

 to the " Chess Editor, Knowledge Office," aud posted before 

 the 10th of each month. 



Solution nf Problem in April number. — 1. Q to B7, and 

 mates next move. 



Correct Solutions received from H. S. Brandreth,C. T. 

 Blanshard, A. H. C. Hamilton, " T. Wells." 



