September 13, 1906] 



NA TURE 



499 



priately devoted to considering the different conceptions 

 which have been held with regard to matter, culminating 

 in the theory of atomic disintegration, which had its birth 

 in Montreal in 1902. 



At the end of an interesting and instructive paper in a 

 recent number of the Chemiker Zeitung (No. 61, p. 742) 

 on the chemical composition of the eruptive products of 

 volcanic actions, and more especially that of Vesuvius in 

 April of this year. Prof. Julius Stoklasa, of Prague, directs 

 attention to the meagre primitive equipment of the Royal 

 Seismological Observatory situated in the immediate neigh- 

 bourhood of Vesuvius, where on April 3 Prof. Matteucci 

 observed the first subterranean signs of this year's eruption, 

 and which Prof. Stoklasa visited in May last. In this 

 article Prof. .Stoklasa throws out the suggestion that the 

 observatory should be re-modelled and made an inter- 

 national experimental station with geophysical and chemical 

 laboratories, similar, in fact, to the International Biological 

 Station at Naples, which is being provided with extensions 

 to its physiological and chemical laboratories for the pur- 

 pose of more thoroughly investigating marine fauna and 

 flora. 



In 1903, from the occurrence of a number of lines 

 common to the spectra of krypton and xenon. Dr. Baly in- 

 ferred the existence of a new element present as an impurity 

 in those gases. From a study of the spectra of different 

 fractions of the most easily condensable portion of the inert 

 gases of the atmosphere. Dr. Rudolf Schmidt now concludes 

 in the Verhandlungen of the German Physical Society 

 (vol. viii.. No. 14) that xenon is not a true element, but a 

 mixture, possibly of several gases. The ultra-violet spec- 

 trum between ^ = 3450 and A = 2800 of one fraction of the 

 gas was found to contain only about forty lines, the greater 

 part corresponding with those ascribed to xenon ; several, 

 however, were new. Within the same range Baly measured 

 about 500 lines, and the difference in the two numbers 

 might at first sight appear to be due to insuflicient illumin- 

 ation in the one case. This view is contradicted, however, 

 by the fact that some of the lines which appeared feeblest 

 in Baly's spectra showed the greatest intensity in the case 

 of this particular fraction, whilst all the brightest lines 

 of " xenon " were missing. The only explanation appears 

 to be that the gas hitherto called xenon is a more or less 

 complex mixture. 



The Country Press, 19 Ball Street, Kensington, W., 

 has added to its series of nature-study picture postcards 

 twelve cards, which may be obtained for one shilling, de- 

 picting twenty-three species of British grasses. The 

 popular and botanical names are given in each case, 

 together with the time of flowering and a magnified re- 

 presentation of the fructification. 



The Nagari-pracharina Sabha, of Benares, has published 

 a " Hindi Scientific Glossary," containing the terms 

 employed in most of the sciences, except biology and 

 geology. The glossary has been edited by Mr. Syam 

 Sundar Das, honorary secretary of the Nagari-pracharina 

 Sabha, with the cooperation and assistance of an editorial 

 committee. The glossary is divided into seven parts, deal- 

 ing respectively with terms of geography, astronomy, 

 political economy, chemistry, mathematics, physics, and 

 philosophy. Preference has been given to common and 

 current Hindi terms. In the absence of appropriate Hindi 

 equivalents, certain appropriate terms existing in some of 

 the prevalent vernaculars have been used. When these 

 have failed, the existing Sanskrit terms have been taken 

 or the English terms employed. 

 NO. 1924, VOL. "74] 



OUR ASTRONOMICAL COLUMN. 



Holmes's Comet (1906/). — According to Prof. Wolf's 

 telegram announcing its re-discovery, as published in No. 

 41 18 of the Astronomischc Nachrichten, the photographic 

 magnitude of Holmes's comet on ;\ugust 28 was 15-5. As 

 the comet passed through perihelion on about March 14 it 

 is not likely to become a brilliant object during the present 

 apparition. The corrections to Dr. Zwiers's ephemeris are 

 — 6s. and —2'. 



Finlay's Comet (1906^).— A continuation from M. L. 

 Schulhof's ephemeris for Finlay's comet is given below :— 



The comet will pass about 1° south of f Geminorum on 

 September 20, and about 2° south of 5 Geminorum on 

 September 25. 



Comet i9o6e (Kopff). — A further extract from Herr M. 

 Ebell's ephemeris for Kopff 's comet (1906^) is given 

 below : — 



Epher, 



Sept. 16 

 18 



Herr Ebell calculated two sets of elements, obtaining 

 October 16, 1905, and May 14, 1906, as the respective 

 times of perihelion passage, but, as seen from the residuals 

 (observed-calculated), there is considerable uncertamty 

 attaching to the calculated path. , t- /- 



Two other sets of elements, communicated by Frot. k.. C. 

 Pickering, give April 12, 1907, and December 7, 1906, 

 respectively, as the time of perihelion, and the resultant 

 ephemerides show the comet's brightness to be increasing 

 at the present time. Observing at Hamburg on August 23, 

 Dr. Graff found that the comet had a coma of o ^5 

 diameter, with a nucleus of magnitude 12-5, the magnitude 

 of the whole being 11-5 (Astronomische Nachrichten. 

 No. 4118). 



The Planet Mercury.— Continuing his articles in the 

 Observatory (No. 374) on planets and planetary observ- 

 ations, Mr. Denning this month discusses the best times 

 and methods of observing Mercury. Dealing with the 

 legendary lament of Copernicus that he had never seen 

 this planet, Mr. Denning expresses his doubts as to its 

 authenticity. The late Rev. S. J. Johnson saw Mercury 

 as an evening star about 150 times during the years 1858- 

 190=;, whilst Mr. Denning has seen it some 130 times 

 since Februarv, 1868, and suggests that, if looked for 

 reffularlv this elusive object may probably be seen on 

 about fifteen occasions per annum in the English climate. 

 In the spring. Mercury should be looked for some days 

 before the maximum elongation, but in the autumn 

 apparitions some days after the elongation. After dis- 

 cussing the observing conditions. Mr. Denning proceeds o 

 describe the surface markings as seen— with great difficulty 

 —on the telescopic image of Mercury since the time ot 

 Schroter. 



Observations of Satellites.— Prof. Barnard observed 

 the sixth satellite of Jupiter nine times, on February 27 

 and March 20, during last winter, and found it quite an 

 easy object, under fair weather conditions, with the 40-inch 

 refractor of the Yerkes Observatory. 



On Februarv 27 the magnitude was 140, and on 

 March 20, when Jupiter was lower down at the time of 

 observation, it was estimated as 14-5. The positions deter- 

 mined from these observations are recorded in No. 41 12 

 of the Astronowische Nachrichten. 



In No. 4116 of the same journal the same observer 



