520 



NATURli 



i^u,. .,M,L.. 6, 192;, 







>nii<lii- 

 I'tof. 



I'l.-i 



iMH.k 



\\. Minknu-:ki, \ ' 



hltcl l,v I i: I . r. I,' 



(.! I ■ ! Will' ■.:■.;, imp 



1: • !i.- Ih.-(,.v ,,| i,'|,,ii' 



J)( .1111. i. il , 



tldll ■ Mt 1 



I' I rniiii lll> h 1 1 .111 ,l,il<-ii I .\ 



St. 'Ill •, 1 he. .1 \- (.1 l\- !,il 1\ It \ .■ 



Ir.llisl.llr,! l.\ II I -li 



a liii id lii-.ti iiK .il ,1 I.: < 'I r •• ' ■ ■■ 



i\i'l.lll\ It \ , '! he ( llilllli .il I 



1 .1)1 iii.l;, iIimIiii'^ with 1 ■ ' : .nuni . 111 < • 



lU'xiiiii with the i lirinii l''ii'^ hllr-^ \\\\\ 



iih hn ic I ■ Ice; t roil bind in v; pn h 1-, h-. m ,1 loin u st mk tun-, 

 ill r.idiation phenomena, and 111 cKi t romagncl i<: 

 reactions (ihf (|nantiini theory and tiie stationary 

 states of tlu' I'xiiir atom are illustrated 1>\' analogy) ; 

 " Radioacti\ it\-," li\- I'lnl. K. iajim-,, translated 



'•■• I ^ wiipcit-r - - ' *'■ <: y- '• < — • 



StriK til! 

 II. Hi !.!-d h "■ bUlc-s \\.\\k: l>ook p: 



( onipreheiiM . of the fin<»-striict»!rp «•• 



as elucidated by the 

 Mathematical .\nalv-: 



tl.r 



I ■;,■ 



Mechanism an 1 



' I,v Prof I- 



loi ma: 1 in' iiiw-ii uiu i' ; : 



mechani uhvsiologv of >' x 



runnuliuii, and in particui 

 dsrhmifit ; a translation, \> 



The Orij^ni <i\. ( ■(liimenLs .ml 

 I' \Ian ? " by I'rof. J . A. Thomson ; 



and ' 1 hi ( iri^in oi Magic and Religion," by W J. 

 Perr ■ ■1.1.' i.:!.tly the growth and spread of 

 reli'j 



Our Astronomical Column. 



liKi H.\i I. 01 Si:i'i i;mhi;k 7. — Mr. W. !•". l)ennin<,' 

 writes: " About 33 descriptions of ihis object, which 

 appeared abont 7 h. pt m. (i..\l.r., were recei\ed 

 from Cornwall, l">e\ onshire, and South Wales. It was 

 of considerable si/e and ! jiilliancv, and it left a trail 

 which remained visible tor 10 or \i minntc Mug 



to several of the observers. .\ number ol rts 



which have been received arc not of aiu scienutic 

 utility, for they are mere descriptions of the brightness 

 of the phenomenon without including any precise 

 details of the position of the flight and duration. Some 

 of the observations, however, contain all the data 

 necessary for computing the real path of the meteor. 



" The radiant point is indicated at 260^-12", and 

 the height from about (><) to jf) miles di'sccndin^ along 

 a course 100 miles in ieiii^th, at a velocaty of jo miles 

 per second. It extended from south-west of Land's 

 End to about 25 miles west of T-undy Island, and it 

 lit up brilliantly the sea and coast of Cornwall in the 

 district nearly over w hu h the meteor descended." 



Prof. Lindemann's Theory of the Spiral 

 Nerul.^. — The Observatory for September contains 

 two articles criticising this theory, which suggested 

 that the spirals were clouds of cosmic dust, expelled 

 from the galaxy by light-pressure, and shining by 

 reflected starlight. Prof. Perrine considers the idea 

 of their shining by reflected light untenable, on the 

 ground that at least one of them, N.G.C. 1068, has 

 some bright lines in its spectrum, which show the 

 same radial velocity as the dark ones ; in case of 

 retlcction the latter would be double the former. 

 Mr. A. C. Gifford notes that the presence of layers 

 of dark obstructing matter in many of the s])irals 

 negatives the idea of reflected light from tlie .nalaxy, 

 a point which was also made by Mr. Reynolds. 



Prof. Perrine agrees with the suggestion of expulsion 

 from the galaxy, but holds that the spirals are no 

 longer merely dust clouds, but that a large number 

 of stars have formed in them by condensation ; they 

 are autonomous systems, perhaps 100 light-years in 

 diameter ; the novae in them are supposed to be 

 similar to, but perhaps smaller than, galactic novae ; 

 they may be caused by stars colliding with streams 

 of cosmic dust. 



Mr. Gifford notes that Lick Observatory photo- 

 graphs show that the number of spirals approaches 

 a million ; assuming with Lindemann that each has a 

 mass of ten thousand suns, we obtain an aggregate 

 mass greater than we can reasonably suppose to have 



been expelled from tip , since it exceeds man\- 



estimates of the united aiu.ss of the galactic st.o- 

 lie A'^iro with i'ernne m supposing that the spir,d> 

 ont.iin mails- condensed and ascribes ttie 



no\ (■ observe 1 to collision- a ith star. 



Sol MM- 1; -\ NO I HI 'd;.wii\,, - • 'Fr OF LiGHT. 



— Prof. I . J. J. S( e and othe: .ately asserted 



that J. Soldner had anticipated Emstein in 1801 in 

 announcing the double shift of light-rays passing near 

 the sun. R. Trumpler examines the matter in Pub. 

 Ast. Soc. Pacific for August, and shows, as might be 

 expected, that the double value arises solely from an 

 arithmetical blunder of Soldner's, who wais of course 

 using the Newtonian Law. Soldner's aim was to 

 find the deflexion due not to the sun, but to the 

 earth. Curiously enough, a second arithmetical 

 blunder caused his result to be ten times too great, 

 i.e. 0001" instead of ooooi' ; boili v:diies are far too 

 small for practical measuremen 



The charge of plagiarism a.: istein is thus 



shown to be completeh unfuun le 1 i avendish had 

 investigated the shift at al»oiit the same time as 

 Soldner, but did not get the erroneous double value. 

 Thev both assumed the corpuscular theory^ of light. 

 ddic idea that the sinft was to be expected on the 

 wa\e tlicor\' came much later. 



Star-gauges at I-ixd ( )p.servatory. — Nos. 30 

 and 31 of the Lund Meddelanden contain some useful 

 work on star-gauging. The t'v: "arrangement 



of the gauges of Sir William a; 1 )hn Herschel. 



They are reduced to galactic longitude and latitude, 

 and expressed as star density per square degree in each 

 region measured. References given to the 



sheets of the iranklm .Vdam- mtaining the 



region ; the .greatest and least numtiers per square 

 degree are 9630 and j-x 



No. 31 contains details of the star-counts made at 

 Lund on the lYanklin Adams charts. Separate figures 

 are given for each ma.iinitude down to the 15th and 

 for different distances from the centre of the plate. 

 The density per stjuare degree in each zone is also 

 given. It 'will be remembered that Chapman and 

 Alelotte published a similar studv of these plates in 

 the memoirs of the K.V.S. Ilowex er, as there is room 

 for personality in the estimates of magnitude, an 

 independent count is quite useful. At present there 

 is no general discussion of tlie results of the count, 

 but this will doubtless follow , in the meantime the 

 work is verv serviceable for reference. 



NO. 2814, VOL. I 12] 



