440 



NA TURE 



[February io, 1910 



The twelfth edition, revised, of Mr. W. T. Lynn's small 

 volume on " Celestial Motions " has been published by 

 Messrs. S. Brigster and Sons, Ltd., price 2i. net. The 

 book is an easy introduction to the main facts of astro- 

 nomical science, and the frequent re-issues enable the 

 author to keep it up-to-date. 

 Mr. John Browning has issued the fourth edition, re- 

 itten and revised, of his concise little book "How to 

 \\'ork with the Spectroscope." The book provides 

 beginners with a handy guide to the use of spectroscopes 

 of various kinds, including McClean's star spectroscope, 

 the microspectroscope, and others ; and we welcome it as 

 a simple means of extending the circle of observers of 

 spectroscopic phenomena. The price of the book, with a 

 coloured chart of spectra, is \s. 6d., and without the 

 chart, gd. 



OUR ASTRONOMICAL COLUMN. 



New Elements for Hallev's Comet. — In a note appear- 

 ing in No. 4iq of the Observatory (February, p. 104), a set 

 of elements for Halley's comet, deduced by Mr. C. J. 

 Merfield from the observations made since the re-discovery 

 of the comet in September last, is compared with the 

 elements predicted for this return, as follows : — time of 

 perihelion passage, April 10-6394 (G.M.T.), w=iio° 43' 24" 

 ( = predicted 4- 68"), « =57° 15' 56" ( = predicted-i6"), 

 i=i62° 12' 34" ( = predicted— 8"), c = o-967300 ( = pre- 

 dictedH-o-ooooig"), and ;t = 46.6723" ( = predicted 4-0-003"). 

 From these elements Mr. ' Cromnielin has calculated the 

 conditions for the comet's transit over the sun, and finds 

 that the first contact should take place on May 

 i8d. I4h. 22m. (G.M.T.) in position angle 264°. Thirty 

 minutes later the centres of the two bodies will be at their 

 least separation, the comet being 62" south. Last contact 

 should occur at ish. 22m., in position angle 92°, and the 

 horizontal paralla.\ of the comet will be 54-4", or 45-7" 

 relative to the sun. The transit will be visible in Australia, 

 the Pacific, and Asia, and it is sincerely to be hoped that 

 careful and comprehensive observations will be made, for 

 they may provide useful additions to our knowledge con- 

 cerning the constitution of the denser portions of the 

 comet. 



In the same journal Father Cortie discusses the alleged 

 Papal excommunication of Halley's comet (" The Devil, 

 the Turk and the Comet ") in 1456, and quotes conclusive 

 evidence showing the story to be a myth. 



Studies of Sol.-\r and Stellar Spectra. — In two recent 

 communications to the Academy of Sciences (Comptes 

 rendiis, Xos. i and 3), Count A. de Gramont publishes 

 sorne interesting results as to the occurrence of what he 

 designates raies uliimes in the spectra of the sun and 

 various stellar types. 



The raif!: iiltimes of an element are those lines which 

 persist in the spectrum throughout the range of fiame, arc, 

 and spark conditions. Treating dilTerent alloys in which 

 the quantity of a component continuously decreases, M. 

 de Gramont finds that the first lines to disappear from the 

 spectrum are the " spark " lines, then those produced in 

 the arc, and lastly the " flame " lines ; the most persistent 

 lines are the raies uliimes. On the hypothesis that the spectra 

 of the various regions of the sun are dissociation spectra, 

 and that their differences are due principally to variations 

 of the proportions of elements present, M. de Gramont 

 hopes to find indications which will show, more or less, the 

 regions of the sun, and he gives a list of the most persistent 

 and the most sensible lines of seventeen elements already 

 traced in the solar spectrum. 



M. de Gramont further points out that the absence of the 

 lines of the metalloids, &c., from the solar spectrum should 

 not be accepted as proof that these substances do not 

 pxist_ in the sun, for he has alreadv shown that the 

 ■" ultimate " lines of many of them exist in the more re- 

 frangible part of the spectrum which our atmosphere 

 absorbs. The " ultimate " lines of gold occur at \X 2676-0 

 and 2428-1, and it is suggested that this is the reason that 

 gold has, so far, been considered as absent from the sun. 

 NO. 2102, VOL. 82] 



In the second paper M. de Gramont considers the distri- 

 bution of raies ultimes in different stellar types, having 

 studied for this purpose the Harvard classifications, the 

 numerous publications of Sir Norman Lockyer, and the 

 works of Sir William Huggins. Using the nomenclature 

 of Miss Cannon, in the Draper Catalogue, he finds that 

 these ultimate lines do not occur in the hottest stars, 

 but make their appearance in B8A, the Algohan type, 

 and generally increase in intensity as the lower types 

 are reached. In the c division tl^ " ultimate " lines 

 appear at a stage later, and in less numbers, than in the 

 a division. M. de Gramont points out that the c division 

 corresponds with Sir Norman Lockyer's " ascending 

 series," of which the most characteristic types are the 

 Rigelian and the Cygnian, in which predominates the 

 " test spectrum " or spectrum of enhanced lines. The 

 presence of oxygen and nitrogen lines in the helium stars, 

 lines dissimilar to the ultimate lines, is taken as an indica- 

 tion that in such stars powerful electrical discharges are 

 in action. 



M. de Gramont concludes by suggesting that the presence 

 or absence of " ultimate lines " in the spectra of stars 

 may furnish valuable indications of the relative tempera- 

 tures, or the stage of evolution, of the different types, and 

 is equally applicable to the Harvard classification and the 

 conceptions of Sir Norman Lockyer. 



Markings on Mars. — ^Too late for insertion at the end 

 of his letter on Martian markings as seen with small and 

 large telescopes, published in last week's Nature (p. 397), 

 Prof. Lowell writes : — " It will prove of interest to 

 students of the subject that this optical shattering of lines, 

 due to a large glass, is precisely what M. ."Kntoniadi 

 observed at Meudon in his observations of Mars. He saw 

 in the canals, in place of lines, a tesselated series of dots. 

 His observed mosaic effect is the exact theoretic effect that 

 a large .aperture should produce on continuous lines such 

 as the canals, and always does produce in the case of the 

 rings in the images of a star." 



Elements and Ephemeris for Tempel's Comet (1S73 11.). 

 — In No. 4386 of the Astronomische Nachrichten M. 

 Maubant gives the elements and a search-ephemeris for 

 Tempel's second comet, which is expected to pass through 

 perihelion in the near future. The conditions are not 

 favourable for observation. 



THE NEW COMET (igioa). 



A LTHOUGH by its increasing distance from the sun 

 ■^ and the earth, and by its apparent recession into 

 the sun's rays, the great comet of 1910 is becoming less 

 popular as a spectacle, the interest among astronomers as 

 to the results accruing from the mass of observations will 

 doubtless continue for a long period. From observers 

 situated in many parts of Europe and Africa we are 

 receiving further evidence of this comet's title to rank 

 among the " great comets " of history. 



In sending us the drawing here reproduced, Father Cortie 

 encloses some valuable observations of the comet's appear- 

 ance on January 26. The drawing was made by Mr. 

 William McKeon, an assistant at the Stonyhurst College 

 Observatory, at 6 p.m. January 26, and in making the 

 observations a small pocket telescope of i^ inches aperture 

 and 17 inches focal length was employed. The following 

 are Mr. McKeon's remarks concerning the comet's appear- 

 ance at the time : — " Nucleus of the comet bright and 

 sharp ; no merging into the tail, magnitude 2. Nucleus of 

 comet 2° S. and 7° W. of Venus (estimated). The tail 

 terminated at a star of about the seventh magnitude some 

 8° N. by E. of the head. The star to the right of the 

 comet (N. by W.) was of about the third or fourth 

 magnitude." 



Father Cortie identifies this latter star as o Equulei, 

 magnitude 4-1. and thence deduces that the length of the 

 tail, as seen in the small telescope employed, was about 

 j\°. Naked-eye observations bv himself showed the tail 

 extending almost to e Pegasi, which would make its length 

 12°; its breadth at the end, he estimated, was about 3°. 

 The sky was perfectly clear, and the tail of the comet 



