io6 



KNOWLEDGE & SCIENTIFIC NEWS. 



[May 1904. 



The Face of the Sky for 

 May. 



By W. Shackleton, F.R.A.S. 



The Su.n'. — On the ist the Sun rises at 4.35, and sets 

 at 7.20; on the 31st he rises at 3.52, and sets at 8.4. 



Sunspots and facuhe should be looked for whenever- it 

 is fine ; the positions of the spots with respect to the 

 equator and pole may be derived from the following 

 table :— 



The Moo.\ : — 



May 8 .. 

 22 . . 



.\pogee 

 Perigee 



4 18 p.m. 

 10 30 p.m. 



Occulta-tions. 



There are only two occultations of fairly bright stars 

 observable at convenient hours during the whole month. 

 The particulars are as follows : — 



The Planets. — Mercury will be observable for the 

 first four or five days of the month ; he should be looked 

 for in the N.N.W. immediately after sunset at about an 

 altitude of 15". He is bright enough to be visible to the 

 naked eye, but any slight optical aid will be of great 

 assistance in detecting him in the strong twilight. The 

 planet moves so rapidly that he is in inferior conjunction 

 with the sun on the 13th. 



\'enus is a morning star throughout the month, rising 

 only a short time in advance of tlie sun, and being for all 

 practical purposes unobservable. 



Mars is in conjunction with the sun on the 30th, and 

 is therefore out of range. 



Pallas is in opposition on the i6th, when the magni- 

 tude is 8-5. On this date, the minor planet has the same 

 R..\. as 7 Herculis, but is situated 6" north of the star. 



Jupiter is a morning star, rising about 3 a.m. 



Saturn is also a morning star, rising about 1.20 a.m. 

 near the middle of the month ; he is in quadrature with 

 the sun on the nth. 



Uranus rises about 11.30 p.m. near the beginning of 

 the month, and about g.30 p.m. towards the end of the 

 month. The planet is situated 4 mins. E. of 4 Sagittarii, 

 and, observing with a low power eyepiece, can be seen 

 in the same field of view as the star. 



Neptune sets too soon for observation. 



Meteors. — The principal shower during May is the 

 Aqnarids. This maybe looked for between May i-6; 

 the radiant being in R.A. 22 h. 32 m., Dec. S. 2°., near 

 the star -n Aquarii. 



The Stars. — About 10 p.m. at the middle of the month 

 the followdng constellations may be observed : 



Zemth . Ursa ^lajor. 



North . Polaris ; to the right, Draco and Cepheus ; 

 below, Cassiopeia ; Perseus to the left. 



South . I-]o6tes and \'irgo, Avcturus and Spica a 

 little E. of the meridian ; Leo to the S.W. 



West . Gemini and Cancer ; Taurus to N.W. ; 

 and Procyon to S.W. 



East . Lyra (Vega), Corona, Hercules, and 



Ophiuchus ; Cygnus to N.E.,and Scorpio in S.E. 



Telescopic Objects: — 



Double Stars: — ^ Libra?, XI\'.'' 46™, S. 15- 39', mags. 

 3, 6 ; separation 230" ; very wide pair. 



ff Coronae, XVI.'' ii"", N. 34° 7', mags. 6, 61; separa- 

 tion 4"'4 ; binary. 



a Herculis, XX'II.'' lo", N. 14° 30, mags. 2i, 6; 

 separation 4"-q. \'ery pretty double, with good contrast 

 of colours, the brighter component being orange, the 

 other blue. 



{Herculis XX'H.^ 11™, N. 24° 57 , mags. 3, 8; separa- 

 tion 17". 



Clusters. — M13 (cluster in Hercules) situated about 

 J the distance from t) to '( Herculis, and is just visible to 

 the naked eye. It is a globular cluster, and with a 3 or 

 4-inch telescope the outlymg parts of the cluster can 

 be resolved intu a conglomeration of stars. 



•'^i ^*^ ^'^ ^*i ^^ 



Brass Stripping. 



Electrolysis, which deposits surface films of metal, has lately 

 been put to an ingenious industrial use in stripping metals. 

 Professor C. F. Burgess records a method of stripping super- 

 fluous brass from the joints of bicycle frames by using an elec- 

 tric current with a solution of sodium nitrate. The firm which 

 has adopted the method used to make use of hand lalionr. 

 which damaged the tubes, and afterwards of chemicals, such 

 as potassium cyanide, which were expensive and slow. By 

 this reversal of the principle of electrolytic deposition the brass 

 can be cleaned off the tube joints in from five to forty-five 

 minutes at a scarcely appreciable cost. 



Calcium as arv Industrial Metal. 



Pkoff.ssor Borchers, of Aix-la-Chapelle, has succeeded, after 

 overcoming many difficulties, in producing calcium by a new 

 electrolytic process, by which, it is said, the metal can be ob- 

 tained at a very low cost. It is now being extracted on a 

 large scale, and there should be a great future before it, for, 

 while of very common occurrence, calcium possesses certain 

 properties, such as a great affinityfor oxygen.which should make 

 It a very desirable innovation in the iron industries. Exposed to 

 moist air the metal rapidly becomes coated with oxide ; but it 

 nevertheless possesses many characteristics which may prove 

 of value in the arts. It is fairly hard (harder than lead), can 

 be hammered into leaf, and is very light, having a specific 

 gravity of only 1-58, or much less than that of aluminium 



