6i6 



NA TURE 



[April 30, 1908 



investigation ; tlie apparent inconstancy of the amount of 

 asymmetry contrary to theory, also the apparent asym- 

 metric intensities observed in the components of various 

 lines. Careful measurements of tlie width of the lines 

 show that the mean value is about 0-07 Angstrom unit, 

 and that the asymmetry amounts to about half this 

 amount. 



Sir AViLi.iAM Ramsay contributes to the May number of 

 Casscll's Magazine a popular article under the title " How 

 Discoveries are made," in which he refers, among other 

 matters, to the work of Priestley, Scheele, and Cavendish 

 on air and combustion ; Crookes, Lenard, and Rbntgen on 

 kathode rays ; and Soddy and himself on radium emana- 

 tion and its decomposition into helium, leading up to a 

 short statement as to ;8 rays and the corpuscular theory of 

 electricity. The article provides general readers with a 

 glimpse of scientific work, and is a welcome feature in a 

 popular magazine. 



The Institute of Chemistry has published a second 

 edition of the " List of Official Chemical Appointments." 

 It has been compiled by direction of the council of the 

 institute, and under the supervision of the proceedings 

 committee, by Mr. Richard B. Pilcher, registrar and 

 secretary of the institute. The scheme adopted in the first 

 edition has been adhered to, the information has been 

 corrected carefully, and numerous additions, including an 

 index of names, have been made. The list is arranged in 

 two main divisions ; the first contains appointments in the 

 British Isles, and the second in India, Canada, Australia, 

 British colonies and protectorates, Egypt, and the Sudan 

 provinces. The appointments dealt with include those under 

 .State departments, local authorities, and public institu- 

 tions, in addition to teaching posts at universities, colleges, 

 and schools. An appendix gives concise information as 

 to societies for the advancement of chemical science and of 

 professional chemical interests. The publication, the price 

 of which is 2S. net, should prove of great service to all 

 who are interested in the applications of chemistry to 

 .State purposes and in the teaching of the science at its 

 various stages. 



OUR ASTRONOMICAL COLUMN. 



Astronomical Occurrences in May : — 

 May I. 8h. 46m. to I2h. 28m. Transit of Jupiter's Sat. III. 

 (Ganymede). 



3. 2lh. 59m. Venus in conjunction with the Moon. 



Venus 4° 15' N. 



4. Sh. 48m. to 9h. 46m. Moon occults fx Geminorum 



(mag. y2). 



5. oh. 51m. Neptune in conjunction with the Moon. 



Neptune 1° 20' S. 



6. 22h. 41m. Jupiter in conjunction with the Moon. 



Jupiter 1° 47' S. 



7. loh. 56ni. Minimum of Algol {0 Persei). 



15. Venus. Illuminated portion of disc = 0"388. 



,, 8h. 42m. to I3h. 31m. Transit of Jupiter's Sat. IV. 

 (Callisto). 



16. Iih. 15m. to I2h. 22m. Moon occults i// Ophiuchi 



(mag. 4-6). 

 19. 8h. 34m. Uranus in conjunction wilh the Moon. 



Uranus 0° 31;' N. 

 24. 23h. 47m. Saturn in conjunction with the Moon. 



Saturn 3° 15' N. 



29. Venus at maximum brilliancy. 



30. 9h. 25m. Minimum of Algol (/3 Persei). 



31. I3h. 52m. Mercury in conjunction with the Moon. 



Mercury 2" 19' N. 



.\ Nuw Star-finder.' — The " Metron " star-finder sub- 

 mitted to our examination by the maker, Mr. C. Baker, 

 244 High Holborn, is an ingeniously designed instrument 



NO. 2009, ^'Oh. 77] 



xvhich will enable beginners in astronomy to become prac- 

 tically acquainted with the constellations and the brighter 

 stars, and also with the more important problems usually 

 placed under the heading "The Use of the Globes." It 

 consists of a 4-inch celestial globe mounted on a tripod 

 and stand so that it may be erected for any latitude. A 

 date circle and a loose hour circle round the south pole 

 enable the user to set the globe for any day and hour of 

 the year. There is also a wire grip carrying a circle, with 

 a pointer at its centre, and a pair of telescopic sights. 

 Having set the globe for latitude, oriented it north and 

 south by the fixed compass, and levelled the stand by 

 means of the two bubbles set in it, the user sets the hour 

 circle according to the directions, and places the pointer 

 over the star, on the globe, which he wishes to locate and 

 recognise ; the real star may then be seen in the centre 

 of the telescope field. In this way a number of constella- 

 tions and important stars, of which the names are given 

 on the globe, may be recognised. Conversely, knowing 

 the date and the position of the star, the approximate time 

 may be determined ; special sights are supplied for work 

 on the sun. To facilitate the reading of the globe and 

 circles when working at night, a small electric lamp — and 

 dry cell — is fitted to the stand. 



The whole apparatus is nicely finished in nickel plate, 

 and should prove useful in demonstrating problems in 

 astronomy to beginners. For anything like accurate work, 

 the apparatus in its present form and size is, we believe, 

 on too small a scale ; a very small error in the setting 

 produces great confusion when magnified on the celestial 

 vault, and the unaided beginner would probablv find that 

 his knowledge of the constellations was not considerably 

 enlarged ; when he began to be familiar with the instru- 

 ment and the stars he would find in the combination a 

 source of many hours of interesting work and problem- 

 solving. Spare globes, covered with blank paper, may 

 be obtained for the purpose of plotting the apparent path< 

 of planets, &c. ; on the present globe we notice one or two 

 misspellings, e.g. Sygnus, Delphin, as the names of con- 

 stellations. The price of the instrument, complete in box, 

 is 2/. 12s. 6d. 



Saturn's Rings. — In No. 4243 of the Astronomischc 

 Nachrichten, pp. 289 to 313 are devoted to records and 

 discussions of observations of Saturn made by various 

 observers during the end of 1907 and the beginning of the 

 present year. Prof. Lowell and Mr. Lampland give the 

 details of the Flagstaff observations, and the former dis- 

 cusses the appearance of the edge of the ring system and 

 of the condensations remarked by Prof. Barnard, them- 

 selves, and other observers. When observing the shadow 

 of the rings on the ball of the planet, all the Flagstaff 

 observers noticed that it was traversed by a medial core 

 the blackness of which was far more intense than that of 

 the boundaries. This core was first observed on June iq. 

 1007, and was plainly visible on subsequent occasions; on 

 November 5 the shadow generally was of a faint cherrv- 

 rcd tinge, and the black medial line was slightly undula- 

 tory. showing irregularities of outline. Drawing con- 

 clusions from the discussion of his results, Prof. Lowell 

 finds that the rings approach more nearly to the body of 

 the planet than hitherto measured, and that the middle 

 and inner members of the ring systems are not flat rings, 

 but tores; this would account for the condensations 

 observed, and for the medial core of the shadow. 



The Systematic Motions of the Stars. — From the 

 analytical study of the motions of iioo stars having proper 

 motions of between 20" to 80" per century, and distributed 

 over both hemispheres. Prof. Dyson has obtained results 

 which confirm those previously obtained by Kapteyn and 

 Eddington, viz. that the stars are moving in tvifo streams. 



The positions found for the apices of the two streams 

 as found bv the different observers are shown below : — 



Stn 



Kapteyn ... R. A. 85°, Dec. - 11° 

 Eddington ... ,, 90°, ,, -19° 

 Dyson „ 94°, ,, - 7° 



R.A. 260°, Dec. -48= 

 ,, 292°, ,, -58° 

 ,, 240°, ,, -74" 



The quick-moving stars considered in the latest dis- 

 cussion show the two distinct drifts very pronouncedly, 

 particularly in the case of Stream 11. For Stream I. the 



