SCIENCE-GOSSIP. 



311 



CONDUCTED BY FRANK C. DENNETT. 



Sun 



Moon 



April 



.. 7 •• 



17 .. 



27 .. 



.. 7 .. 

 17 .. 



Mercury.. 



Venus 



Mars 



Jupiter 

 Saturn 

 Uranus 



Rises, 

 h.m. 



5.23 a.m. 

 5-1 

 4.41 



Rises. 

 7.9 a.m. 

 8.4 p.m. 

 2.59 a.m. 



Souths, 

 h. m. 



Sets. 



h.m. 

 ... 6.41 p.m. 

 ... 6.57 

 ... 7-14 



Souths. 

 .. 4.2 p.m. 

 ..12.34 

 .. 8.48 a.m. 



Semi 

 Diameter. 



Position at Noon. 

 R.A. 



Dec. 



7° 2' N. 

 10° 40' 

 14° 0' 



h.m. 

 .. 1.6 ... 

 .. 1.43 ••• 



.. 2.20 ... 



Sets. 

 .. 0.0 a.m. 

 ■ • 4-29 

 .. 2.52 p.m. 



Position at Noon. 

 R.A. 



0.24 p.m. 

 0.59 

 1. 17 

 1-45 

 0.57 



.•• 3 

 ... 3" 

 ...24" 

 ...27" 

 7 ... 11.58 a.m. ...29" 

 • 3" 



5.31 p.m. 



5-14 



4.58 



S.27 



2.10 a.m. 



2.2 



Neptune... 7 ... 4.3 p.m. ... i" 2 



h.m. 

 1.28 

 2.42 



3.40 



250 



2.41 



2.21 



6.35 



6.58 



7.21 



10.12 , 



15-52 



15-44 



5.8 



Dec. 



9° 6' N. 

 17" 30' 

 22" 20' 

 23° 17' N. 

 22= 37' 

 19° 47' 

 25= 15' N. 

 24° 43' 

 23° 59' 

 12° 33' N 

 17° 52' S- 

 19° 33' S- 

 21" 33' N- 



Moon's Phases. 



h.m. 



4.24 a.m. 1st Qr. ... April 10 



6.25 a.m. 3rd Qr. ... ,, 23 



h.m. 

 8.27 a.m. 

 g.48 p.m. 



New ...April 2 . 

 Full ... ,, 17 . 



Sun. — Spots of considerable size continue to 

 appear on the disc. During February and the 

 early days of March much of interest showed itself 

 both in actual change of appearance in the spots 

 themselves and in real motion on the sun's disc. 



Mercury is in superior conjunction with the 

 sun at 3 a.m. on April 2nd, but from about the 

 23rd to the end of the month is well placed for 

 observation, setting more than two hours after the 

 sun. He will be found very near the Pleiades, the 

 cluster of bright stars in Taurus, about 1° south on 

 the 27th, on which night he sets about 9.25. He 

 shines with a brilliant, rosy light. He reaches 

 greatest elongation east, 20° 33', on April 28th. 



Venus is visible early in the month, but at 7 p.m. 

 on the 2Sth is in inferior conjunction with the sun. 

 She is situated between a Arietis and the Pleiades all 

 the month ; her appearance is that of a crescent, 

 growing narrower every day. To observers using 

 an equatorial she may possibly be observed close 

 to conjunction, a few degrees north of the sun. 



Mars is a tiny object, only observable with 

 fairly large telescopes. He is in the constellation 

 Gemini. At the beginning of the month he forms 

 a triangle with the third-magnitude stars fi and e 

 Geminorum, and at the end he lies to the south- 

 west of Pollux. 



Jupiter is in Leo, between Regulus and p Leonis 

 on the ist, and gradually retrograding towards the 

 former. He sets at 4.45 a.m. on April ist, and at 

 2.49 a.m. on April 30th, so is visible all the even- 

 ing hours, in good position. 



S.-^turn rises about 10.44 P-ni. on the ist, and 

 at 8.4 1 on the evening of the 30th. Were it 

 not for his great south declination he would be a 

 magnificent object. On the 15th the outer major 



axis of the outer ring is 42"-35, and the outer minor 

 axis i7"'47, whilst the angular diameter of the 

 planet is i6'-8, so that the rings extend bej-ond the 

 poles. It is situate west-north-west of ;3 Scorpia. 



Meteors should be looked for on April nth, 

 12th, 19th, and 2oth. 



Variable Stars visible during April are : — 



R.A. 

 h.m. 

 S Virginis 13.26 



" ^°^''^ \ 14.10 



(Arcturus) ' 

 LL. 26325 Bootis 14.18 



Dec. 

 6° 31' S. 



19° 49' N. 



8° 38' N. 



Magnitude. 

 Max. Mill. Period. 

 6'o ii'o 373'6 days. 



6-5 



8'5 



The Rotation Period of Jupiter. — The mo^t 

 recent determination is by Herr A. A. Nyland, 

 who, from observations on some of the markings, 

 gives a period rather exceeding 9h. 55m. 30s., 

 which is the period found by Beer and Miidler. 

 The late Sir G. B. Airy, in 1834, made it gh. 55m. 

 21S., whilst Professor Schmidt, in 1866, gave as a 

 mean 9h. 55m. 46-3S. To obtain the exact rotation 

 may appear easy to those unacquainted with close 

 Jovian observation, but, as a fact, is practically an 

 impossibility, because different objects give dif- 

 ferent periods. In 1880 Mr. H. Pratt gave gh. 

 55m. 33"9s. as the period determined by observa- 

 tions on the great red spot. Mr. W. F. Denning, 

 observing bright spots in the Equatorial Zone, 

 found a period of gh. 50m. 5s., whilst from dark 

 spots in the north Temperate Zone the same observer 

 found the period was only a little over gh. 48m. 

 So that at the same time three classes of objects 

 were giving three different rotation periods, differ- 

 ing to the extent of more than seven minutes of 

 time. 



Brilliant Meteor.— Mr. S. H. R. Salmon, 

 M.B.A.A., of South Croydon, writes to the "English 

 Mechanic " : " On February 20th, 6h. 3m. 30s. p.m., 

 I was admiring Venus in strong twilight, and turned 

 eastward to see if Jupiter was yet visible, when an 

 exceptionally splendid meteor fell from Gemini to- 

 ward the head of Leo Major. It seemed to 

 originate near Castor, and was quite equal to 

 Venus in lustre, although not so white. When, in 

 its fall, it was about equidistant from Castor and 

 the horizon, it divided, the following portion being 

 fainter, and having a reddish tinge. Then all 

 quickly vanished, without any report that I could 

 detect." Is this the same meteor that was ob- 

 served at Dover the same evening ? Did any of 

 our friends see it ? 



Jupiter's Satellites. — In 1877-S1 the writer 

 made 424 observations of the relative brilliance of 

 these little bodies, finding as a result that it could 

 be represented thus : III : I, II ; IV. I, was usually 

 brightest in that half of its orbit nearest the earth, 

 especially when east of Jupiter. II ; was brightest 

 to the east of Jupiter, especially in the quadrant of 

 its orbit nearest the earth. Ill : was brightest in 

 the eastern half of its orbit, especially that part 

 farthest from the earth, whilst it was faintest in the 

 portion corresponding on the west of the planet. 

 IV. was brightest in west superior and east inferior 

 quadrants, and faintest in west inferior. II ; was the 

 most constant in brilliance, whilst IV. was the most 

 variable. It almost seemed as if, like our own 

 moon, they always presented the same face to 

 the planet, but, unlike our own satellite, had 

 atmospheres with considerable changes in meteoro- 

 logical condition, 



' Variable in colour, yellow tc yellowish red. 

 t Variable in colour, yellowish white to reddish. 



