NATURE 



[November 5, 1908 



We have received from the Pulsometer Engineering 

 Co., Ltd., a copy of their latest catalogue of " Geryk " 

 air-pumps. The list also contains a full description of 

 the Fleuss patent pump for desiccating or for steam con- 

 densers, wliich has been awarded a diploma for a gold 

 medal in connection with the Franco-British Exhibition. 

 These pumps are specially designed for desiccating, 

 chemical work, distillation, and so on, their special feature 

 being that they will pump condensable vapours of alcohol, 

 ether, &c., to a high vacuum as readily as ordinary dry 

 air. 



Dr. Robert A. Lyster's "School Hygiene," published 

 by Mr. W. B. Clive, has reached a second edition. A 

 chapter dealing with the organisation of medical inspection 

 in schools has been added to the new edition. 



Messrs. George Bell and Sons have published an 

 «ighth edition of Dr. Percy Groom's " Elementary 

 Botany." Two new chapters have been added, dealing 

 respectively with " Form and Function " and " Soil and 

 Distribution of British Plants," and some additional notes 

 have been interspersed in the text. 



A FOURTH edition of Mr. J. M. Lowson's "Text-book 

 of Botany " has been published by Mr. W. B. Clive. The 

 book has been enlarged by the addition of new matter, and 

 several changes have been made. The sections dealing 

 with the stelar theory have been re-written, and the life- 

 history of Hffimatococcus, and a chapter on ecology and 

 plant distribution, have been introduced. 



The first part of a work on the " Geologic der Stein- 

 kohlenlager," by Dr. Dannenberg, has been published by 

 the firm of Gebriider Borntrager, Berlin. The second 

 volume will probably appear at the end of next year, and 

 we propose to defer our notice of the work until that part 

 reaches us. 



0\]R ASTRONOMICAL COLUMN. 



The Spectrum of Comet Morehouse, 1908c. — In a com- 

 munication to the Coinptes rendus (No. 16, October 19, 

 p. 6b6) MM. A. de la Baume Pluvinel and F. Baldet give 

 an account of the spectrum of comet 1908c as photographed 

 by them at the Juvisy Observatory on October 4, 5, and 7. 



The instrument used was that previously employed for 

 the photographing of the spectra of comets 19026 and 

 igoyd, an objective-prism camera of o-oS m. aperture 

 and 0-30 m. focal length, the angle of the prism being 

 20" 18'; the results are, therefore, comparable. Wratten's 



pinacyanol " plates were used. 



On each plate there appear seven monochromatic images 

 of the comet, of which the approximate wave-lengths are 

 465-458, 448, 421. 397. 388-385, 376, and 367. Of these, 

 the first image was faint and without a tail, the second 

 more intense, with tail, the third the most intense of all, 

 with a very extensive tail, and the fourth was but a little 

 Ipss intense than the third. The image at \ 38S-385 was 

 of an extended nebulous character degrading towards the 

 violet, the tail being confused. Evidence of change 

 appears at A 376, for whilst a tail accompanies the feeble 

 image obtliined on October 5, there is none accompanying 

 the more intense image of October 7 ; the image at \ 367 

 is extremely faint. 



The spectrum displays the absence of the hydrocarbons, 

 which were a feature of that of Daniel's comet, whilst 'he 

 complete system of the cyanogen spectrum — so far as 

 possible under the observing conditions — is represented ; 

 usually the band at \ 388 only is represented in cometary 

 spectra. The origin of the radiation at \ 397 is unknown. 

 The monochromatic images of the tail extend to some 

 34' from_ the nucleus, thus being relatively long as com- 

 pared with those of Daniel's comet, despite the fact that 

 ihe nucleus of the latter was more intense. 



NO. 2036, VOL. 79] 



Solar Vortices and their Magnetic Effects. — An 

 account of an interesting research by Prof. Hale on solar 

 vortices and their magnetic effects appeared recently in 

 this Journal (August 20, pp. 368, 369). Prof. Zeeman 

 also contributed an account expressing his opinion as to 

 the interpretation of the results obtained. Prof. Zeeman 

 has now sent us an advance proof of a communication he 

 made to the meeting of the physical section of the eightieth 

 gathering of the Deutscher Naturforscher und Arzte at 

 Cologne on September 23, which contains further important 

 results communicated by Prof. Hale. 



It will be remembered that Hale examined the spec- 

 trum of a sun-spot situated near the middle of the solar 

 disc, using a Fresnel rhomb and Nicol prism mounted in 

 front of the slit of the spectroscope, and obtained results 

 which indicated the Zeeman effect. When a sun-spot is 

 near the middle of the solar disc, the direction of the 

 light from the spot is along lines of force which are at 

 right angles to the plane of the vortices in which the 

 electric currents are encircling. The changes in the lines 

 in the spectrum of the spot are due, therefore, to the 

 " longitudinal effect," as termed by Voigt, and this is 

 what Prof. Hale observed. 



If now the sun-spot be on the limb of the sun, the 

 light from the spot will be observed in a direction at right 

 angles to the lines of force, or in the plane of the circu- 

 lating electric currents. The lines in the spectrum should 

 then be plane polarised, and show the " transversal effect." 

 The important new fact which Prof. Zeeman gives in his 

 paper is that this observation has now been made by 

 Prof. Hale, who has reported as follows : — " Vortices 

 rotating opposite directions show opposite polarities ; 

 spot lines near limb plane polarised." 



The observations of both these longitudinal and trans- 

 versal effects indicate very conclusively that sun-spots are 

 very intense magnetic fields, and this important discovery 

 will certainly stimulate work on many allied investiga- 

 tions. 



The W-we-length of the H5 LiNE.^In No. 2, vol. 

 xxviii., of the Astrophysical Journal (p. 162, September), 

 Mr. Evershed gives the results he has obtained from 

 measurements of the wave-length of the H5 and Ht lines 

 in the solar spectrum. 



Previous observers have called in question Rowland's 

 value (410200) for the H5 line, but, according to Jewell, 

 the position given in the " Preliminary Table of Wave- 

 lengths " is most probably correct. 



On photographs taken with a specially designed grating 

 spectrograph, during 1907, Mr. Evershed measured the 

 fine absorption line superposed on the bright emission line 

 of the chromosphere, a spectrum suitable for this purpose 

 being obtained by placing the slit of the spectrograph 

 slightly within the limb of the sun's image. The results 

 obtained were not numerous or accordant enough to give 

 a definitive value for H5, but they do show conclusively, 

 in Mr. Evershed's opinion, that the line does not differ 

 appreciably from its theoretical position derived from 

 Balmer's formula for the series. The recently determined 

 mean value is 4101-900, the theoretical value being 

 4101-893. From measurements of the bright He line, Mr. 

 Evershed obtains the mean value \ 3970-212, whilst the 

 theoretical value is 3970225. 



Meteoric Iron and .'\rtificial Steel. — From the council 

 of the Iron and Steel Institute we have received a reprint 

 (No. 3, 1907) from the Journal which contains a paper by 

 Prof. Fredk. Berwerth, of Vienna, in which the author 

 shows that there is a close connection between meteoric 

 iron and steelworks' steel. Many of the characteristics of 

 meteoric irons can be reproduced artificially, and Profs. 

 .■\rnold and McWilliam have even been able to produce a 

 steel, with 039 per cent, of carbon, on which the 

 Widmannstatten figures can be formed. 



Proceeding, Prof. Berwerth gives a list of fifteen con- 

 stituents of meteoric irons and their compositions, and also 

 directs attention to the comprehensive character of the 

 collection of meteorites to be found in the Imperial Natural 

 History Museum at Vienna. This collection includes falls 

 from 615 different localities, weighing altogether nearly 

 35 tons. Of these, 232 are iron, 28 iron or stone, and 

 355 stones without iron. 



