August 17, 1S93J 



NATURE 



379 



lution yielded a precipitate of the while sulphide upon the 

 addition of a dilute acid. When this sulphide, GeSj, was 

 heated in a current of hydrogen, small glittering scales of the 

 lower sulphide, GeS, much resembling crystals of specular iron 

 ore, were formed just beyond the heated portion of the tube ; 

 upon continued heating complete reduction occurred, metallic 

 germanium itself biing deposited upon the walls of the tube in 

 small greyish-white octahedral crystals which exhibited a 

 particularly brilliant metallic lustre. 



Canfieliiite, upon analysis, yields numbers which indicate that 

 its composition is AggGeSj, or 4Ag.jS.GeS.j. Prof. Penfield 

 points out that the published analysis of Prof. Winkler's for 

 argyroJite agrees much better with the same formula than with 

 the formula 3Ag„S. GeS,, which he ascribes to it in his memoir. 

 Prof. Pcnfiekl confirms this by another analysis of argyrodite 

 conducted with an excellent specimen in his possession. The 

 two minerals would thus appear to possess the same composi- 

 tion. They are not identical, however, for argyrodite crystal- 

 lises in the monoclinic system. Canfi Idite crystallises in cubic 

 octahedrons modified by dodecahedral faces ; the crystals are 

 black wiih a blue or purple sheen, they exhibit a magnificent 

 metallic lustre and are extremely brittle. Argyrodite and can- 

 fieldite are therefore dimorphous forms of silver germanium 

 sulphide. 



Notes from the Marine Biological Station, Plymouth. — Last 

 week's captures include the liyAxoKA Myriothela phrygia, the 

 semi-parasitic Rhabdoccele Fecampia erythrocephaia, and the 

 Mollusca I'avorinus albtis and Rostanga coccinea. The floating 

 fauna has changed very sli^jhlly since last week, but several 

 other autumn forms have made their appearance. Radiolaria 

 have been present in f.iir numbers ; the Anthomedusa J'odo- 

 coryne (= Dyanorphosa) carnea\i3s been plentiful, ihe majority 

 possessing buds upon the manubrium ; and the beau;iful larva; 

 of the Prosobianch jf/jjoa and of the Opisthobranch .'Egirus 

 punctiluceiis have also been taken. The Turbellaria Fecampia 

 erythrocephaia and Cycloporus fapillosus, and the Crustacean 

 Hyas coarclattts are now breeding. 



The additions to the Zoological Society's Gardens during the 

 past week include two Ruffed Lemurs {Lemur varius, i 9 ) from 

 Madagascar, presented by Mis. Brightwen ; three Long-eared 

 Owls (Asia oltis) and one Tanny Owl (Syrniiim aluco) from 



Europe, presented by Mr. Edmund Hart, F.Z. S. ; a 



Falcon (Falco ) from , presented by Lord Lilford, 



F.Z. S. ; five shags (Phalacrocorax graculus) from Scotland, 

 presented by the Maclaine of Lochbuie ; a Common Chameleon 

 (Chamcrleon vulgaris) from North A'rica, presented by Mr. E. 

 Palmer; a Black-headed Caique (Caica mtlanocephala) from 

 Dtmerara, deposited ; a Regent Bird (Sericiilus melintis) from 

 Australia, purchased. 



OUR ASTRONOMICAL COLUMN. 



The Origin of New Si ars. — Prof. A. W. Bickerton writes 

 to us from Christchurch, New Zealand, as follows : — " More 

 than a year hai eUpsed since the first notice appeared of 

 the new star in Aurigse, and up to date no generally-accepted 

 explanation of the special phenomena noted has been oflered in 

 any of the leading journals. May I beg to draw the 

 attention of your readers to several articles bearing 

 directly upon the mode of origin of new stars, puljlished 

 fifteen years ago in the Transactions of the N.Z. Institute? 

 The explanation there offered appears to fit in almost exactly 



iwiih the actual conditions as observed in this particular case. 

 The paptrs referred to are contained in vols. Ii, I2, and 13 of 

 I the Transactions of the N.Z. Institute. A summary of these 

 I papers also appears in the Proceedings of the Australasian 

 Assoc ation for the Advancement of Science for the year 1891." 

 pon referiing to the above references we find that Prof. 



July II. July 12. 

 600 ...601 



NO. I ?42, VOL. 48] 



Bickerton believes that new stars are caused by the "grazing" 

 collision of stars like the sun. His researches show that " The 

 temperature developed is independent of the amount of grazing. 

 With similar substances it depends only on the velocity destroyed, 

 so that the coalesced body produced by the merest graze must 

 be as hot as though the whole sun collided. The molecular 

 velocity of such a high temperature may be sufficient to carry 

 away every particle entirely into space, the mass of the body 

 not having sufficient attractive power to retain them. Hence an 

 intensely brilliant body is produced in less than an hour ; it 

 then expands and increases in size and total luminosity for per- 

 haps a few hours to a day or so ; then the diffusion v/ould be so 

 great as to gradually lessen luminosity, until in a few months or 

 a year the star would have disappeared into space. This re- 

 presents all the peculiarities of temporary stars. If the graze 

 be more considerable the attraction will be greater, yet the 

 molecular velocity is the same : a hollow globe of gas mny then 

 result, giving us a planetary nebula. According to Lord Lindsay 

 this is the condition of the temporary star in the Swan." 



The Spectrum of the Rordame-Quenisset Comet.— 

 Prof Campbell in Astronomische Nachrichten, No. 3177, gives 

 a detailed account of the visual and photographic observations 

 that he has made of the spectrum of this comet at the Lick 

 Observatory. The following are the visual observations, and 

 in the fourth column are given Kayser and Runge's wave-lengths 

 for the edges of carbon bands. 



r , Carbon Description of bright lines 



J"'5"7- bands. and bands. 



— ...619 595. ..Maximum of red band, 

 broad, faint. 

 562 ... — ... — ... 563. ..Red edge of yellow band. 



— ... — ■■•5633 ... 5635. ..Very faint li;ie terminating 



in yellow band. 



— .. — ... 558 ... 5585. ..Bright line in yellow.band. 

 5l62'l...5l6r8...5i63'9... 5i65'2 Very bright line terminat- 

 ing in green band. 



5124 ...5127 ...5128 ... 5129 ..Very bright line terminat- 

 ing in green bnnd. 



— ... — • ... 509 ... — ...Very bright line terminat- 



ing in green band. 

 4734 .. — ... — ... 4737. ..Red edge of blue band. 



— ... — •••4734 ••• 4737 ..Bright line terminating blue 



band. 



— ... 434 ... — ... ' — ...Bright region in continuous 



spectrum, faint. 



— ... 421 ... — ... — ...Bright region in continuous 



spectrum, faint. 



In addition Prof. Campbell has obtained two photographs 

 of the comet-spectrum extending from wave-length 487 to 387. 

 Twenty-eight bright lines have had their positions determined 

 in the photographic spectrum, fourteen of which appear 'o cor- 

 respond to Unas and bands of carbon and cyanogen as giv;n by 

 Kayser and Runge. It is pointed out, however, that the wave- 

 lengths of the comet-lines are systematically less than Kayser 

 and Runge's by one or two tenth-metres. Prof. Campbell 

 thinks this may in part be due to the fact that the cometary 

 spectrum consists of unsymmetrical bands rather thau lines, 

 and partly to motion in the line of sight. 



Atmospheric Refractionaxd Star Photographs.— Now 

 that stellar parallax is determined from photographic data, and 

 a catalogue of stars is being prepared from the images impressed 

 by celestial points upon sensitive films, it becomes necessary to 

 investigate the effect of each and every cause tending to vitiate 

 the results. Prof. A. A. Rambaut considers the most import- 

 ant of these disturbing causes in a paper on the distortipn of 

 photographic star images due to refraction read before the 

 Royal Dublin Society on April 19, and just published in a 

 separate form. Prof. Rambaut had previously published for- 

 mula; {.-istr. Nach. 3125), by which the correction for refraction 

 to the relative position of any two stars on a photographic plate 

 can be computed in a convenient manner, and he has now fol- 

 lowed these up by determining the distortion that takes place 

 in the shape of a star-image during the exposure. His conclu- 

 sion is that within the limits of an exposure of fifteen minutes' 

 duration, "so long as the zenith distance does not exceed 60° 

 no sensible error can arise through the distortion of a star 

 by refraction if the measures are in all cases made from the 

 centre of the image, and the coefficients in the frmulae of 

 reduction are computed for the time corresponding to the middle 



