I70 



NATURE 



[August 5, 1909 



photometers of the Bunsen t)pe are to be preferred to 

 those of the flicker type. He considers the latter, although 

 more sensitive than the former, give readings for the com- 

 parative brightness of the two lamps about 6 per cent, 

 from the true value. lie finds photometers of the Lummer 

 type come short of the Bunsen in sensitiveness, and he 

 thinks that in time the Bunsen will displace the other 

 photometers at present in use. 



Bi'LLETiN No. 30 of the University of Illinois consists 

 of an important paper, by Mr. J. K. Clement, on the 

 rate of formation of carbon mono.xide in gas producers. 

 The numerous theoretical works on the processes taking 

 place in the fuel bed of the producer have been built up on 

 a rather slender experimental basis, and the present com- 

 munication fills a decided gap in our knowledge. The 

 experiments deal more especially with the rate of forma- 

 tion of CO in the reaction CO. -l-C = 2CO, previous re- 

 searches having been rather directed to the study of the 

 final equilibrium than to the rate at which the re- 

 action takes place. Three authors contribute to this 

 memoir, J. K. Clement, L. H. Adams, and C. N. Raskins, 

 dealing with the subject from the physical, chemical, and 

 mathematical point of view respectively. The result of 

 this collaboration is a valuable monograph, which cannot 

 be neglected by anyone interested in gas producers. 



Mr. W. B. Clive has published a second edition of Mr. 

 William Hall's " Modern Navigation." The tc.xt-book 

 deals also with nautical astronomy, and is intended to 

 meet the needs of cadets of the Royal Navy and the 

 syllabus of the Board of Education. The scope of the 

 volume is limited to instruction in navigation so far as, 

 and including, the problem of fixing position by one posi- 

 tion line derived from sights of the sun and another 

 derived from a bearing of land. The book has been 

 entirely re-cast. Its price is 75. 61/. 



An abstract of Dr. Jdhn Morrow's contribution to 

 part iii. of the third volume of the Proceedings of the 

 University of Durham Philosophical Society was published 

 in Nature of July 29 (vol. Ixxxi., p. 128). The volume 

 contains, in addition, other articles of interest, among 

 which the following may be mentioned : — Prof. Thornton 

 describes a new method of measuring ti ; Prof. G. H. 

 Stanley contributes a note on an artificial formation of 

 zincite ; Dr. D. Woolacott writes on borings at Derwent- 

 haugh and Dunston ; Mr. A. S. Home describes observa- 

 tions on protoplasmic structure and streaming in potato ; 

 Messrs. Harold Crofts, H. Tiplady, and A. Forster 

 •discuss certain chemical e.xperiments ; and Messrs. T. 

 Herdman and E. Merrick record observations in local 

 geology. The third report of the Boulders Committee is 

 also included in the volume. 



OJJR ASTRONOMICAL COLUMN. 

 _ Movements in the Sun's UprER .Atmosphere.— In con- 

 tinuation of his previous papers, giving the results of the 

 solar researches carried on at Meudon, M. Deslandres 

 has a paper in No. 3 of the Comptes rendus (p. 179, 

 July 19) wherein he describes and discusses more recent 

 results dealing with the question of motion in the upper 

 layers of the- solar atmosphere. First he mentions the 

 connections previously shown to exist between spots, 

 "filaments," and " alignements," and points out that 

 owing to the greater size, frequency, and distribution of 

 the latter, they afford much more trustworthy and con- 

 tmucius data on which to base any researches or theories 

 dealing Avith solar changes than docs the study of spots 

 alone ; but for any exhaustive study of these phenomena 

 the velocities of the solar vapours in' the line of sight must 

 be determined, and it is to this determination that M. 

 Deslandres has in the more recent work returned. .^s 

 NO. 2075, VOL. 81I 



Meudon 'is the only observatory employing the spectro- 

 cnrigistreur des vitesscs radiates, the results are of great 

 interest. 



To measure the radial velocities all over the disc would 

 take much more time than the Meudon staff are able to 

 devote to the work, so, for the present, only those in the 

 neighbourhood of filaments near the centre of the disc 

 have been measured. A diagram of a typical radial- 

 velocity curve shows that in the filament, shown on the 



Kj" image, the vapours are moving towards the observer, 

 the displacement of the line being towards the violet. 

 At first glance this appears to contradict M. Deslandres's 

 previous conclusions, and the fact that whilst, in May 

 and June, when spots were scarce, or small, the filaments 

 were well developed, yet further suggests that the two 

 phenomena are not physically connected ; but M. 

 Deslandres thinks it necessary only to modify and enlarge 

 these conclusions, and shows how solar convection currents, 

 analogous to Benard's cellular liquid tourbillons, would 

 account for the apparent discrepancy of the results, and, 

 at the same thiie, afford an explanation of Evershed's 

 radial motions observed in the penumbra; of spots. 



Searcii-ephemerides for Comet 1896 VII. (Perrine). — 

 In No. 4342 of the Astroiiomische Nncbrichtcn Herr F. W. 

 Ristenpart publishes a set of elements, brought up to the 

 equinox of 1910, for the comet discovered by Perrine in 

 i<S9G ; the time of the next perihelion passage is given as 

 1909 November 412 (M.T. Berlin). Three search- 

 cpheinerldes, computed from the elements by Messrs. R. 

 Castro and A. Repenning, are also given, T being taken 

 as October 275, November 45, and November 12-5 re- 

 spectively. .According to the second epheincris, the comet 

 is at present in Pegasus (.August 6. I2h. M.T. Berlin, 

 a = 23h. 44-2m., 5=4-31° 402'), and will apparently travel, 

 in a north-easterly direction, through .Andromeda towards 

 Perseus; on August 24 its position should be a = oh. ii-4m., 

 5 = 4-40° 124', and the comet should appear about as 

 bright as when discovered. The computed brightnesses at 

 perihelion are 6, 13, and 205 respectively, according to 

 the date of perihelion passage. 



Observations of Jupiter. — Some incidental measures of 

 the positions of Jupiter's belts and of the polar diameter 

 of the planet arc given by Prof. Barnard in No. 433q of 

 the Astroiiomische Nachrichtcii (pp. 307-10). For each 

 recognisable feature he gives the distances from the south 

 and north limbs and the apparent latitude ; the observation 

 on February 19 8h. om. (central standard time), 11107, 

 gave the apparent polar diameter as 40-78", and, reducing 

 this to A = 520, the polar diameter therefore becomes 

 3611". 



On this date a narrow south belt, 2" wide, in apparent 

 latitude —9-88'', showed several ill-defined w'hite spots, and 

 on May 26, 1908, the north equatorial belt was double for 

 part of its length. 



The Orbit of X Sagittarii, a Cepheid \'ariable. — 

 The variability of the star X Sagittarii was discovered by 

 Schmidt in 1886, and the radial velocity detected by 

 Slipher in 1904. In No. 157 of the Lick Observatory 

 Bulletins Mr. J. H. Moore discusses a series of one- 

 prism and three-prism spectrograms taken at Mount 

 Hamilton during the period 1904-S. Plotting the velocity- 

 and the light-curves for the same epoch, it is shown that 

 the times of light-maximum and of greatest velocity of 

 approach agree very closely, this being a fundamental 

 characteristic, as Mr. .Albrecht has shown, of all variables 

 of the 6 Cephci tyf>e. No such close agreement is shown, 

 however, between the epochs of light-minima and 

 maximum recession. 



The Leeds .Astronomical Society. — The energy and 

 activity of the Leeds Astronomical Society in popularising 

 the study of astronomy is well illustrated in the Journal 

 and Transactions for iqo8. This journal contains abstracts 

 of the papers read before the society, and a large number 

 of astronomical notes contributed to various periodicals by 

 Messrs. Elgle and Whitmell, members of the committee. 

 .Among the former there appear papers on sundials (Mr. 

 T. Wright), variable stars (Mr. Ivo Gregg), and " other 

 inhabited worlds " (Mr. T. Benton), while an interesting 

 popular paper dealing with the fancied figures in the moon 

 is contributed by Mr. Elgie. 



