542 



NA TURE 



[September 28, 1905 



notes are contributed by Mr. Nelson on the presence of 

 a flagellum at each end of the tubercle bacillus, by Lord 

 Rayleigh on an optical paradox, and by Dr. Lazarus 

 Barlow on a new form of hot stage. The usual summary 

 of current researches concludes this excellent quarterly. 



Messrs. Charles Griffin and Co., Ltd., have published 

 a sixth edition of Mr. Andrew Jamieson's " Elementary 

 Manual of Magnetism and Electricity." Several additions 

 have been made in this new edition. 



A KEY to the exercises in the second part of Mr. Pendle- 

 bury's " New School Arithmetic " has been prepared by 

 the author and published by Messrs. George Bell and Sons. 

 The price of the " Key " is %&. bd. net. 



Messrs. .Smith, Elder and Co. have published a sixth 

 edition of Marshall and Hurst's " Junior Course of 

 Practical Zoology." The new edition has been revised 

 throughout by Dr. F. \V. Gamble, who has also added 

 short accounts of Monocystis, Coccidium, and Obelia. 



The following popular science lectures will be given 

 at the Royal Victoria Hall, Waterloo Bridge Road, S.E., 

 during next month : — October 3, "A Journey of Surprises : 

 through Yunnan to Tonquin," Mrs. Archibald Little; 

 October 10, " Smokeless Explosives," Mr. J. S. S. Brame ; 

 October 17, " The Plants of Other Days : what their 

 Fruits and Seeds were Like," Mr. H. E. H. Smedley ; 

 October 24, " My Cruise Around Spain and Portugal," 

 Mr. F. W. Gill. 



Messrs. Philip Harris and Co., Ltd., Birmingham, 

 have just issued the third edition of their valuable cata- 

 logue of scientific instruments required in all departments 

 of instruction or research in physics. The volume con- 

 tains five hundred pages and is lavishly illustrated, a 

 large number of the pictures representing new instruments 

 or new methods of illustrating the principles of physical 

 science. Many manuals and text-books of physics used 

 in schools have been consulted, and novel forms of 

 apparatus described in them are now made by Messrs. 

 Harris, and appear in the present catalogue. The volume 

 is well bound, and should be very useful for reference by 

 teachers of physics in schools and colleges. Ko doubt it 

 will find a permanent place on the bookshelves of many 

 laboratories and lecture-rooms. 



OUR ASTRONOMICAL COLUMN. 



Astronomical Occurrences in October: — 

 Oct. I. Sh. 52m. Minimum of Algol (fl Persei). 

 ,, 4. 5h. 4ini. ,, ,, ,, 



,, S. gh. Mars in conjunction with Uranus (Mars 1° 48' S.). 

 ,, II. S.ilurn. Major axis of ring =42"'2S, Minor axis = 



8" -46. 

 ,, 14. I5h. Mars in conjunction with A Sagittarii (mag. 



2-9), Mars 0° 7' N. 

 ,, 15. Venus. Illuminated portion of disc =0'868, of Mars 



= o86[. 

 ,, 19-22. Epoch of October meteoric shower (Radiant 



92+15'). 

 ,, 20. 6h. 5ini, to Sh. 12m. Transit of Jupiter's Sat. HL 



(Ganymede 1. 

 ,, 21. loh. 35ni. Minimum of Algol (fl Persei). 

 ,, 23. iSh. 24m. to igh. 30m. Moon occults p Leonis 



(mag. 3-8). 

 ,, 24. 7h. 23m. Minimum of Algol (;8 Persei). 

 ,, 27. loh. 15m. to llh. 35m. Transit of Jupiter's Sat. HL 



(Ganymede). 

 ,, 31. Uranus in conjunction with i Sagittarii (mag. 5'3). 



Nova Aquil.^. — Further news concerning Nova Aquilae 

 No. 2 is published in No. 4047 of the Astronomischc 

 Nachrichten. It appears that Mrs. Fleming discovered the 



NO. 1874, VOL. 72] 



existence of the Nova whilst examining the Draper 

 memorial photographs on August 31. A photograph of 

 the spectrum, taken on August 18, shows the hydrogen 

 lines H5, H7, and H3 bright and broad, also faint traces 

 of the bright bands at \ 4472 and \ 4646. On that date 

 the magnitude of the Nova was about 65, on August 21 

 it was 7-5, whilst on August 26 it had fallen to lo.o. No 

 trace of the Nova is visible on a plate taken on August 10, 

 although stars of magnitude 9-5 are shown thereon. A 

 plate taken with the Bruce telescope at Arequipa on 

 August 15, with an exposure of four hours, contains 

 images of sixteenth-magnitude stars, but not of any object 

 which can be recognised as the Nova. 



A chart of the region, published by Prof. Wolf, shows 

 the position of the Nova in regard to the star B.D. 

 — 4°.4663, and further shows that the Nova occupies a posi- 

 tion between two spaces which are void of stars down 

 to the fifteenth magnitude. 



Ephemeris of the Variable .Asteroid (167) Urda. — In 

 No. 4047 of the Astronomischc Nachriclitcn Herr A. 

 Berberich publishes an ephemeris for the asteroid Urda, 

 which Dr. Palisa recently showed to be variable. 



The following is an extract from this ephemeris, which 

 was calculated from the elements published in the " Jahr- 

 buch " and for i2h. M.T. Berlin : — 



1905 a S log >■ log A 



0-2875 

 0-3044 



Observations made on August 31 and September 5 gave 

 corrections to the above of -(-4s. and -Ho' -8. 



The following figures indicate the changes of magni- 

 tude which were observed during the period July 30- 

 September 5 : — 



Time July 30 .4ug. 31 Sept. 5 



Magnitude 13-0 ... 11. o ... 120 



The Ultra-violet Chromospheric Spectru.m., — M the 

 total eclipse of 1900 M. H. Deslandres devoted his atten- 

 tion to two special researches, of which the first was to 

 obtain the ultra-violet spectrum of the " reversing layer," 

 and the second to obtain a great number of plates showing ■ 

 the bright lines, in order to detect the changes which 

 might take place in the chromosphere in the interval 

 between the second and third contacts. 



In the first research he was successful, and obtained a 

 duplicate series of plates showing the bright spectrum 

 between X 3000 and \ 5000. The first series was obtained 

 with a prismatic camera of i metre focal length, the 

 second with a camera of half this focal length. The 

 prisms employed were of 60° angle, and were made of 

 Iceland spar, whilst the objectives were made up of an 

 achromatic combination of quartz and fluorspar. 



The general results obtained from the reduction of one 

 of the larger negatives, which was exposed for two seconds 

 at second contact, are given in No. 9 (August 28) of the 

 Comptcs rendiis, and deal only with the 157 lines photo- 

 graphed between A 3400 and \ 3066. The chief character- 

 istic of the spectrum in this region, as in the less re- 

 frangible region already known, is the predominance of 

 " enhanced " titanium lines. In fact, M. Deslandres states 

 that, considered as a whole, the spectrum is that of the 

 titanium spark. Vanadium and chromium are represented 

 by lines of less intensity, whilst the iron lines are extremely 

 weak, the enhanced lines being considered in each case. 



The coronal radiations are represented on two other 

 negatives by well defined lines at W 3329.6, 338S o, and 

 3447.7, the last having the greatest intensity. The same 

 negatives, which were exposed for fifteen and thirty 

 seconds respectively, show several prominences, and here, 

 again, the spectrum of titanium predominates. 



The " chronophotographe," an instrument for photo- 

 graphing from six to ten spectra per second at the two 

 contacts, was less successful, the vibration produced by 

 its manipulation spoiling the definition. M. Deslandres 

 gives the details of the instrument, and points out its 

 probable efiiciency if suitably mounted. 



