February 5, 1903] 



NA TURE 



\2Q) 



physics having but a slight knowledge of German could easily 

 follow Prof. Mach's writings, and would gain botli pleasure and 

 profit by becoming acquainted with his many suggestive views. 



AMONG scientific articles in the magazines for February, the 

 following are noteworthy. In the Fortnightly Review, Mr. 

 Maurice Maeterlinck writes of the beauty of field flowers in his 

 usual charming style. Prof. R. A. Gregory contributes to the 

 Comkill Magazine a paper on the astronomy of the unseen, in 

 which he describes the evidence which has been accumulated 

 in recent years as to the existence of dark stars and other non- 

 luminous matter in the stellar universe. The Royal Magazine 

 contains an account, by Mr. W. M. Webb, of school gardens 

 in connection with a number of English schools of different 

 .grades ; the educational value of nature-study in the open air is 

 accentuated in this essay. Mr. F. W. Stokes contributes to 

 the Century Magazine an article on the Aurora Borealis, which 

 is illustrated with four coloured plates reproduced from the 

 author's own paintings. 



The additions to the Zoological Society's Gardens during the 

 past week include a Fennec Fox (Cam's cerdo) from North 

 Africa, presented by Dixon Bey; a Mandrill {Cynocephalns 

 mormon) from West Africa, presented by Mr. M. Vickers ; a 

 Buffon's Touracou (Turacus buffoni) from West Africa, 

 presented by Mr. V. G. Gane ; an Elate Hornbill (Ceralogymna 

 elata) from West Africa, presented by Mr. Francis Hart; a 

 Water Rail {A'allus aquaticus) British, presented by Lieut. - 

 Colonel L. H. Irby ; a Kinkajou (Cercoleptes eaudivolvulus) 

 from South America, a Great Wallaroo (Macrnpus robustits) from 

 South Australia, deposited. 



OUR ASTRONOMICAL COLUMN. 



Comet 1903 a (Giacobini). — The following observations 

 of this comet are reported in No. 3841 of the Astronomische 

 Nachrichten : — 



January 20, 6h. 54m. 12s., Gottingen, o = 22h. 58m. 4s. '8, 5 = 

 + 2° 30' 4". No nucleus. 



January 21, 6h. 22m. os. , Strasburg, R.A. = 22h. 59m. 51s., 

 Dec. = + 2° 44' 8". 



January 21, 7h. 9m. 30s., Heidelberg, R.A.(app.) = 22h. 

 59m. 52s. - 4, Dec. = + 2° 44' 38", mag. = io'O. 



January 22, 6h. 29m. 30s., Heidelberg, R.A.(app.) = 23h. 

 om. 54s. 6, Dec. = +2° 58' 37". 



Return oe Perrine's Comet, 1S96 vii. — Herr Ristenpart 

 has calculated the corrected elements and the ephemeris, given 

 below, for the return of this comet during the present year. 



T = April 26 '6, 1903. 



49 4'' 



1903 



Date 

 Feb. 



L = 35 5o-S 4 -\ 

 02 I 

 a = 242 2o'4o j 



i= 15 4i'2Sj 

 log'/ = 0-54313 



Ephemeris 12//. M.T.Berlin. 

 8 1903 'o log r 



log A 



6-5 

 .. I4'S 



22"fC 



March 2-5 

 April 3-5 

 May 5-5 



- I 27 

 + 021 



+ 2 17 



+ 4 20 



+ 12 47 



+ l8 49 



lime of 



01840 

 0-1670 

 0-1501 



OI337 



o - oSo6 



o -0690 



discovery 



0-3856 

 0-3780 

 03703 

 03627 

 0-3385 

 0-3354 



Bright- 

 ness. 

 0'22 



o 25 



0-28 

 0-31 

 0-44 

 0-47 



(Astronomische 



a 1903-0 



h. m. 

 22 5-9 

 22 28 "O 



22 52'5 



23 '7'4 

 1 9-0 



3 127 

 Unit brightness at 

 Nachrichten, No. 3S41). 



Physical Constitution of Jupiter. — As chairman of the 

 Mathematics and Astronomy Section of the American Associ- 

 ation for the Advancement of Science, Prof. G. W. Hough 

 read a paper on the above subject at the Washington meeting 

 held on December 29. 



After reviewing the history of the observations of Jovian 

 phenomena, Prof. Hough gave a detailed account of his own 



NO. 1736, VOL. 67] 



observations, which date from 1S79. All the measures made 

 by him were micrometrical, and he strongly deprecates the 

 making of mere visual observations wherever it is possible to 

 use a micrometer. Details are given of his measurements of 

 the change of latitude and the rotation period of the Great Red 

 Spot, and the variations are illustrated by four curves which 

 accompany the paper. From the fact that some spots have 

 shorter periods than others, Prof. Hough deduces that the spots 

 must exist at various heights in the planet's atmosphere. 



Some observations of transits and eclipses of the satellites led 

 to the deduction that the satellites have no inherent light of 

 their own and that the planet is not hot enough to produce 

 light. 



Prof. Hough also draws some very interesting conclusions as 

 to the density and general physical constitution of the planet, 

 and the nature of the various markings seen projected on its 

 surface, and these conclusions argue strongly against the theory 

 that the markings — excepting the belts — are of the nature of 

 clouds in the planet's atmosphere. 



The complete address is published in Science for January 16. 



Observations of Variable Stars. — Mr. A. Stanley 

 Williams communicates his observations of thirteen recently 

 discovered variables to No. 529 of the Astronomical Journal. 



DEFINITION OF JUPITER'S MARKINGS. 

 ACCELERATION IN THE MOTION OF 

 THE GREAT RED SPOT. 



'"THE study of Jovian markings has been rendered very diffi- 

 -*- cult for European observers in recent years owing to the 

 position of the planet far south of the equator. Telescopic 

 definition has been rarely good, and the more delicate and 

 diminutive of the surface features have usually been obliterated 

 amid the turmoil of seething vapours in which the image has 

 been involved. The effect of unsteady, confused definition is to 

 smooth off objective irregularities and to produce momentary 

 displacements and contortions, giving rise to false appearances 

 which are sometimes considered real by imaginative or inex- 

 perienced observers. When the disc is affected by 'rushing 

 vapours, the belts often appear as the only distinguishing marks 

 on the planet, and they look even and spotless, so that the 

 observer may readily conclude that Jovian phenomena are 

 temporarily quiescent. But when the disc is outlined with 

 livid sharpness and the details stand out boldly, as they often 

 do in the comparative absence of atmospheric ebullition, the 

 aspect of the planet seems to have been transformed, and a 

 crowd of interesting features immediately present themselves 

 for examination. On special occasions of this kind, it is 

 possible to take between fifty and a hundred transit-times of 

 well-defined marks in the course of a few hours. 



On July 11 and 13, 1902, Jupiter appeared in my 10-inch 

 reflecting telescope under a power of 312, magnificently defined. 

 The whole face of the planet seemed figured over with rugged 

 detail. I saw many features on those nights which were not 

 seen again, though repeatedly looked for with the utmost care. 

 The belt scenery was very diversified, and it struck me as being 

 totally dissimilar to the smooth indefiniteness commonly dis- 

 played under less suitable conditions. During the progress of 

 my observations at Bristol in recent years, I have usually 

 recorded the state of the seeing, and the following is a sum- 

 mary of the records for the last five oppositions of Jupiter : — 

 Observations of Jupiter, 1S9S-1902. 

 I i.-linilion. 



1898 

 1899 

 190O 

 1901 

 1902 



~ o 



-J 

 18 



o.2 



51 

 76 

 36 

 76 





41 



69 



30 

 71 

 81 



8 

 13 



7 

 10 



14 



11 

 20 



9 

 1 1 



15 



11 



19 

 8 



24 

 3' 



6 



10 



4 

 21 



15 



280 

 668 

 307 

 547 

 1005 



5 years 



328 292 25 52 66 93 56 2807 



