September 3, 1908] 



NA TURE 



435 



The Rivista Geograjica Italiana, No. 6 of igoS, contains 

 n short note on the remarkable eruption of Etna on 

 April 29 last. This was preceded by violent earthquakes, 

 and accompanied by the opening; of a fracture of more 

 than a liilometre in length and from 20 to 50 metres in 

 breadth. Several parasitic cones of small size were formed 

 ilong: it, and about 500,000 cubic metres of lava poured i 

 iut, but the fissure was only partially obscured by erupted 

 material, and remained conspicuous after the eruption had 

 ■ cased. Although this eruption was violent while it lasted, 

 .ind although the interval separating it from the next pre- 

 ceding eruption was more than fifteen years, or about 

 two and a half times the average during the last 150 

 years, the eruption was of very short duration, commencing 

 at 5.20 a.m. on April 29 and ceasing at 5.40 p.m. on 

 April 30, but practically lasting for only about seventeen 

 hours. 



The report of the Meteorological Committee for tlie year 

 ending March 31 last contains much useful reading for those 

 interested ir# the development of meteorological science, 

 and shows that great efforts are being made both from 

 practical and theoretical points of view. Many useful 

 publications have been issued during the. year, to some 

 of which we have already referred ; among those still in 

 the press we may specially mention : — (i) meteorological 

 results for the western portion of the Atlantic anticyclone, 

 by Dr. R. H. Scott ; (2) seasons in the British Isles since 

 1S7S ; and (3) summary of hourly values at four observa- 

 tories, 1879-1908. The most important point to be noted 

 in connection with the periodical publications is the revision 

 of the form of the monthly weather report, which gives 

 summaries from all stations in connection with the otTice, 

 either directly or through the meteorological societies and 

 other bodies, and includes a rainfall map contributed by 

 Dr. H. R. Mill. This change is based on the principle 

 that the value of the observations is much enhanced by 

 prompt publication, and now extends to all branches of 

 the work ; e.g. the marine department, under the able 

 superintendence of Commander Hepworth, issues elaborate 

 monthly pilot charts for the Atlantic and Indian Oceans, 

 which include the latest intelligence of use to seamen 

 received by cable from the Canadian and Indian Meteor- 

 ological Services. In view of the importance of a homo- 

 geneous system of weather telegraphy in western Europe, 

 I he committee has changed the hour of reports from 8h. 

 lo 7h. a.m. ; the additional expense of the earlier opening 

 of the telegraph offices gives rise, however, to a serious 

 question of ways and means. The use of wireless tele- 

 grams and the investigation of the upper air are among 

 the many other important matters engaging the earnest 

 attention of the conunittee. 



The June number of Terrestrial Magnetism and .Atmo- 

 spheric Electricity contains a short article on the work of 

 the magnetic survey yacht Galilee from the pen of the 

 director. Dr. L. A. Bauer. During the three years' 

 voyages of the Galilee a complete magnetic survey of the 

 Pacific Ocean was made with scarcely a hitch in the pro- 

 gramme originally sl<etched out for it. The experience 

 gained on board has led to the conclusion that for 

 future work a vessel must be specially constructed, and 

 the Carnegie Institution has undertaken to defray the cost 

 of a new wooden sailing vessel, the Carnegie, 155 feet 

 long, with auxiliary power (125 horse^power) provided by 

 a gas engine, built, so far as possible, of non-magnetic 

 materials, so that the outstanding magnetic effect of the 

 ship will be less than the errors of observation. It is 

 hoped that the ship will be ready next year, when a survey 

 of the Atlantic will be commenced. 

 .NO. 2027, VOL. 78] 



In a further article in the same magazine Dr. Bauer 

 points out that the recent attempts to represent the mag- 

 netic state of the earth by means of spherical harmonics 

 have not led to results of which any practical use can 

 be made, owing to the wide divergence between the calcu- 

 lated and the observed values for any point. This he puts 

 down to the distribution of areas of irregularity of varied 

 amounts and extents over the earth, and the difficulty of 

 representing their - effects analytically without calculating 

 a prohibitive number of terms. He concludes that the 

 time has come to halt in our attempts to calculate more 

 terms, and to fix on a small number as representing the 

 principal features of the magnetic state of the earth with 

 sufficient accuracy, and to deal with each of the residuals 

 separately. 



Moon occulls Tauri 



OUR ASTRONOMICAL COLUMN. 



ASTRONOMIC.VL OCCURRENCES IN SeI'TEMBER : — 



Sept. 7. Venus. Illuminated portion of disc = o-43i ; 27th 

 = 0-568. 

 g. 7h. 56m. to Sh. 56m. Moon occults t- Aquarii 



(mag. 43). . 



10. l6h. gm. 10 i6h. 56m. Moon occults 30 Piscium 



(mag. 47).. 

 u 7h. 45m. Saturn in conjunction with Moon (Saturn 



2' 3i' N.). 



13. iih. 42m. Minimum of Algol ((3 Persei). 



14. gh. Venus at gteatest elongation (46° 2' W.). 



15. I3h. 37m. to I4h. 40m. Moon occults e Tauri 



(mag 37). . „ 



,, Saturn. Outer minor axis of outer ring = 5 'Sa. 



16. 8h. 31m. Minimum of Algol (;3 Persei). 

 ,, i6h. 12m. 10 I7h. 29ro. 



(mag. 4'8). 

 20. igh. Venusinconjunclion with Moon (Venus 5° o' S.). 

 ■>2. I2h. igm. Jupiter in conjunction with Moon (Jupiter 



3'45'S.). 

 22h. 5gm. Sun enters Libra : Aulumn commences. 

 29. igh. Sauirn in opposition to th; Sun. 



Observation of Phcebe, Saturn's Ninth Satellite.— 

 From a note in No. 4270 of the Astronomische Nachrichtert 

 (p. 362, August 21) we learn that photographs of Saturn's 

 ninth satellite, Phoebe, were obtained at Greenwich, with 

 the 30-inch reflector, on July 31, August i, 2, and 3. 

 Provisional measures of the position-angle and distance of 

 the satellite, about 63° and 39' respectively, are given for 

 each date. On August 3 the satellite was at, or very near, 

 eastern elongation, so that these positions, in combination 

 with those determined at western elongation about 

 October 30, 1907, will furnish valuable data for the deter- 

 mination of the mass of Saturn. 



The Parallax of 6i Cvgni. — From meridian observa- 

 tions, made with the small meridian-circle of the Astro- 

 nomical Institute of Heidelberg Observatory, Herr Giorgio 

 .\bctti ■ has determined the parallax of the well-known 

 double star 61 Cygni, and publishes a preliminary com- 

 nuinication of his results in No. 4270 of the Astronomische 

 Nachrichten. These preliminary results give a somewhat 

 lower value than previous determinations, the respective 

 parallaxes of the preceding and following components being 

 -|-o"-24 + o".o5 and -Ho"-22 ±o"-os. 



Prominences at the Sun's Poles. — In No. 7, vol. 

 xxxvii., of the Memorie delta Societd degli Spettroscopisti 

 Italiani (p. 107) Father Fenyi discusses, at some length, 

 the occurrence and appearance of large prominences near 

 the solar poles. The discussion embraces the question as 

 to the epoch of the sun-spot period at which such promin- 

 ences are most frequently seen, and it is shown that their 

 maximum takes place some months after the sun-spot 

 maximum. Among other conclusions. Father Fenyi finds 

 th.at there is a periodical sharp maximum to which it is 

 desirable that further attention should be paid. He also 

 shows that the estimation of the heliographic latitude of 

 the sun's polar cap from the continuous observations of 

 the positions of prominences in regard to the limb is not 



