342 



NATURE 



[November 25, 1915 



It thcrofore became necessary foi- nie to patent this 

 device independently of commercial considerations, and 

 llu .Motomusic Company soon realised its advantages. 

 iiut until the attitude of commercial firms towards 

 scientific inventors has considerably ch.mged I shall 

 continue to avoid undertaking aii\ imcvtii^ation the 

 results of which may be directly cajjable uf commercial 

 application. If this be impossible, I shall continue to 

 follow my previous practice of rendering such inven- 

 tions unpatentable by the method of publication ; and 

 I advise others to do the same. Of course, there is 

 nothing to prevent Germans from exploiting inventions 

 that have been published without previous protection 

 [^c.g. the "Thermos" flask). G. H. Bryan. 



The Aurora Borealis of November 5. 



With reference to the description in Nature of 

 November i8 (p. 314) of the appearanc<- of the aurora 

 borealis in Yorkshire about 7 p.m. on the evening of 

 November 5, I may mention that I saw it at the 

 same time from the neighbourhood of BroadU y Com- 

 mon, in the west of Essex, latitude 51° 45' N." 



It fonned a low, colourless luminous arch on the 

 northern horizon, probably about 6° high and 30° in 

 length. There were no streamers, and no movement 

 was visible. J. 



November 19. 



As a supplement to the observations of .Mr. .Scriven 

 Bolton on the aurora borealis of November 5, and his 

 beautiful illustrative drawing (Nature, November 18), 

 may I be allowed to record the following observa- 

 tions. Mr. Scriven Bolton ceased observing at 7.40 

 p.m.; I began at 8 p.m., although the aurora had 

 been noticed about 7 p.m. The aurora appeared in 

 the form of a bright whitish-green glow, of the form 

 depicted by Mr. Scriven Bolton, extending on the 

 horizon from N. by E., to W. by N., with streamers 

 occasionally rising from it. At 8.25 p.m. the general 

 glow was affected with pulsations, and at 8.40 p.m. 

 five comet-like streamers appeared in the N.\V., and 

 a brighter patch of luminosity X. by W. A single 

 streamer appeared in the N. at 8.45 p.m., and at 

 8.50 p.m. a dark arch formed, separating an upper 

 bright arch from the brightly glowing region beneath. 

 This must not be confounded with the dark segment, 

 so often, seen in aurorae surmounted bv a bright arch. 

 This particular phenomenon I do not remember to 

 have observed' before in auroral displays. 



At 8.55 p.m. the luminous arch rose rapidly, reach- 

 ing to the Pointers of the Great Bear, and' became 

 very bright. It then, 8.58 to 9.0 p.m., divided in the 

 middle, and broke up into luminous clouds, which 

 appeared to drift, until a very bright patch was formed 

 due W. The bright clouds had disappeared by 

 9.2. p.m., but five minutes later the summit of the 

 arch formed again, though it was inuch fainter than 

 before. It then increased in brilliancy, and disap- 

 peared at 9.9 p.m. At 9.12 p.m. a verv bright 

 streamer arose in the N.W. At 9.15 p.m. 'the sky 

 became overcast with dark, filmy stratus clouds. The 

 luminous patch in the W. was^ also observed earlier 

 in the evening, at about 7.0 p.m. The stars seen 

 through these bright clouds were certainlv dimmed in 

 lustre. Looking at the bright glow with a direct- 

 vision prism, I could only see a mere ghost of light 

 in the green. 



The aurora was observed during a disturbance of 

 greater intensity on the magnetic needles. A marked 

 easterly movement in declination was synchronous 

 \yith the formation of the dark arch, and with the 

 rising and marked increase of luminosity of the bright 

 arch. A. L. CoRTiE. 



Stonyhurst College' Observatorv, No\ember 20. 

 NO. 2404, VOL. 96I 



A Remarkable Solar Halo. 



A somewhat remarkable halo was visible at Bristol 

 for more than an hour during the morning of Thurs- 

 day, No\cmber 11, between nine and half-past ten. At 

 nine the sky was bright and almost cloudless ; a couple 

 of hours or so later it was completely overcast and 

 much rain fell. The halo was white with a slight 

 red coloration on the inside edge, and the whole circle 

 was visible. The most striking feature at 9.30 was 

 the clearness of the sky outside the ring, and its dark- 

 ness inside. It looked just like a circular cloud of 

 smoke bounded by a bright ring. When measured 

 by my colleague, Mr. Broadbent, the diameter of the 

 halo was found to be 44° 10'. 



David Robertson. 



Mirchant Venturers' Technical College, Bristol, 

 Noveinber 17. 



Rule for Determining Direction of Precessional 

 Movement. 



Prof. A. M. Wortiiixgto.n' has kindly pointed out 

 to me that my interpretation of Prof. W'atanabe's rule 

 (Nature, October 21, 1915) gives the wrong direction 

 of azimuthal turning for the gyroscope. In my state- 

 ment, jor upper part of the wheel read, lower part of 

 the wheel. A. Gray. 



The University, Glasgow. 



SCIENTIFIC EXPOSITION AT ITS BEST.^ 

 (i) A LL who have enjoyed Sir Ray Lankester's 

 ■^~^ popular essays published in the Daily 

 Telegraph under the title " Science from an Easy 

 Chair," will be glad to have a third instalment 

 of them in permanent form ; those to whom they 

 are new are to be envied. The mood of the essays 

 expresses the conviction that while science is for 

 foresig'ht and the practical mastery of things, it 

 is also for our delight, '' in this world of unending- 

 marvels and beauty." Far from echoing the old 

 moan that increase of knowledge is increase of 

 sorrow, the author declares that science " satisfies 

 man's soul." To accept this generous apprecia- 

 tion it may be necessary, however, to include with 

 " science " the attendant feelings and imaginings 

 which are usually kept at a stern arm's length off. 

 What are the characteristics of these masterly 

 essays, when we get beyond their obvious qualities 

 of learning and lucidity, experience and insight? 

 The first is that Sir Ray Lankester, like Huxley 

 before him, is able to show us the interest and 

 significance of common things. Thus there are 

 illuminating chapters on the sand and pebbles and 

 shells of the sea-shore, on a piece of amber, on 

 sea-anemones and jelly-fish, shrimps and barna- 

 cles, on daddy-long-legs, on Christmas trees, and 

 more besides. It is the function of art and poetry 

 to idealise what we see and do every day ; but 

 science also has its share (for there are really no 

 hard and fast compartmental roles in life) in show- 

 ing us the significance of the commonplace, and 

 fine examples of lucid exposition of difficult, 



1 (i) " Divers'ons of a Naiurali«t." Rv Sir Ray L.•^nke^ter. Pp. XV. + 424 

 (LonHon : Mfthuen and Co., I.tH.) Price 6s. 



f2)"The Birth Time of the World and Other Sripntific Essays." Ry 

 Prof ,T. loly. Pp. XV. + 307. (London: T. Fisher Unwin, 1915.) Price 

 los. 6d. net. 



(3) " Birds and Man." By W. H. Hudson. Pp. 306. (London : Duck- 

 worth and Co., 1915.) Price 6s. net. 



