i88 



NATURE 



[December 20, 19CX) 



In the September number of the Bulletin de la Sociit^ 

 cf Encouragement four P Industrie Nationale, N. S. Kournakow 

 gives an account of his investigations on the alloys formed by 

 sodium and potassium with mercury and of sodium with cad- 

 mium, lead and bismuth. The method employed was the 

 determination of the temperature of fusion. Curves are drawn 

 representing the variation of the temperature of fusion with the 

 composition, and in all cases these curves are characterised by 

 very distinct temperature maxima. In the case of the combin- 

 ation sodium and mercury, no less than seventy-five experiments 

 have been carried out, each with a different proportion of the 

 components. The maxima of temperature referred to are 

 remarkably high — 346° C. in the case of sodium, and mercury, 

 and 2697° C. in the case of potassium and mercury, and the 

 composition of the alloy corresponding to these temperatures is 

 exactly represented by the formulae NaHgj and KHgg. The 

 freezing-point depression curves which proceed from these tem- 

 perature maxima are shown to extend through large temperature 

 intervals. In the case of NaHgj the curve extends from 346° C. 

 to 218° C. on addition of sodium, and to 155° C. on addition of 

 mercury. The combinations of sodium with cadmium, lead and 

 bismuth are also distinguished by very high temperature maxima, 

 these being respectively 395°, 420° and 720° C, whereas the 

 melting-points of the pure metals are Na 96°, Cd 322°, Pb 

 326°, and Bi 268° C. These characteristic temperatures corre- 

 spond exactly with the formulae NaCd^, NajPb, and NasBi. The 

 author draws attention to the similar phenomena which have 

 been observed with the combinations — aluminium and gold, 

 aluminium and antimony— and concludes that in these latter the 

 aluminium functions as an alkali metal, giving rise to the same 

 peculiarities as sodium and potassium in the alloys investigated 

 by himself. 



In Prof. Cook Wilson's letter on the formula of inverse prob- 

 ability (p. 154) the following corrections should be made, though 

 they do no not affect the fundamental argument : In line four 

 of letter, for Cr and P, read C„ and P„ ; in line six, for /, read 

 /„; p. 155, col. 2, line 13, for "in reality" read "on reality" ; 

 in penultimate paragraph, the last word, "strong," should be 

 " strongest " ; and in the eighth line from end," the head " should 



read " this head." . Finally, Prof. Wilson wishes -^^^f^^ (line 

 . . 2^P 



r9. col. i,p.iSS) to read 1^=0. 



From Mr. W. Epgelmann, Leipzig (London : Williams and 

 Norgate), the following scientific works have been received : — 

 The third edition of A. de Bary's " Vorlesungen iiber 

 Bakterien," revised and partly rewritten by Prof. W. Migula ; 

 Part i. of " Studien liber die Verbreitungsmittel der Pfianzen," 

 by Dr. M. Kronfeld, dealing with fertilisation effected by wind ; 

 and two parts of " Das Pflanzenreich," a conspectus of the 

 vegetable kingdom, edited by Prof. A. Engler under the 

 auspices of the Prussian Imperial Academy of Sciences. The 

 plants described in these parts belong to the Musacese, 

 Typhaceae and Sparganiaceae. 



i'hb additions to the Zoological Society's Gardens during the 

 past week include a Chimpanzee {Anthropopithecus troglo- 

 dytes ^'i) from West Africa, presented by Captain W. G. 

 Ambrose ; a Mozambique Monkey {Cercopithecus pygerythrus) 

 from East Africa, presented by Mr. W. J. Langton ; a Lesser 

 W^hite-nosed Monkey {Cercopithecus peiaurista) from West 

 Africa, presented by Miss L. Harold ; a Stair's Monkey {Cerco- 

 pithecus stair si, <J ) from the Lower Zambesi, presented by Miss 

 J. C. S. Purves; a Green M.ovH&.q'^ {Cercopithecus callitrichus) 

 from West Africa, presented by Miss M. A. Reeve ; a Duke of 

 Bedford's Deer {Cervus xanthopygius, 9 ) from Manchuria, pre- 

 sented by H.G. the Duke of Bedford ; a Suricate {Suricata 



NO. 1625, VOL. 63] 



tetradactyla) from South Africa, presented by Captain F. E. 

 Cannot, A.S.C. ; a Spur- winged Goose (Plectropterus gam- 

 bensis) from West Africa, presented by H.E. Colonel F. 

 Cardew, C.M.G. ; a Common Heron {Ardea cifterea), two 

 Mediterranean Peregrine Falcons (/^ai/c^/ww/cMj) from Mogador, 

 presented by Mr. W. T, Barneby ; a Kinkajou {Cercoleptes 

 caudivolvulus) from South America, a Blue-bonnet Parrakeet 

 {Psephotus haetnatorhous) from Australia, an Eupatorian Parra- 

 keet {Palaeornis eupatria) from India, a Patagonian Conure 

 ( Cyanolyseus patagonus) from La Plata, three Caspian Terrapins 

 {Clemmys caspica) from Western Asia, deposited ; two Black- 

 tailed Parrakeets {Polytelis melanura) from Australia, pur- 

 chased. 



OUR ASTRONOMICAL COLUMN. 



'Hew Variable in Cygnus. — Mr, A. Stanley Williams 

 announces in the Astronomische Nachrichten, Bd. 154, No. 

 3675, the detection of a new variable star. Its position is 



R,A. = 2oh. 59m. 50s.\/ o... X 

 Decl. = -1-28° 49' -6 /U»5SO). 



The magnitudes were obtained from measurements of photo- 

 graphs obtained with a Grubb 4*4 inch portrait lens, and were 

 as follows : — 



In the same journal Prof. Kreutz gives a list bringing together 

 all the new variables discovered during the past year. 



Spanish Observations OF THE Eclipse of May 28. — A 

 preliminary report of the observations of the total eclipse of the 

 sun, May 28, made at Plasencia by the official party of Spanish 

 astronomers, has just been issued by Senor Iniguez, director of 

 the Madrid Observatory. The principal objects of the expedi- 

 tion were to record the times of the four contacts, to obtain 

 photographs of the corona, and to determine the position of the 

 green line of the coronal spectrum. The attendant phenomena, 

 however, were not neglected. Among the larger instruments 

 employed were an equatorial refractor of 20 centimetres aper- 

 ture and 3 metres focus, a photographic equatorial of 20 centi- 

 metres aperture and 2 metres focus, a photographic telescope 

 of 16 centimetres aperture and i metre focus, and a six prism 

 visual spectroscope worked in conjunction with a coelostat and 

 horizontal telescope. The weather conditions were excellent, 

 and a very graphic account of the general work of the expedition 

 and of the eclipse itself is given. Five excellent photographs of 

 the corona were obtained, three with the larger and two with 

 the smaller coronagraph. It is remarked that the principal 

 prominences were unconnected with the coronal extensions, and 

 that in one of the photographs the streamers can be traced to a 

 distance of about three diameters. For the green coronal line 

 a wave-length of 5297*3 was determined, as compared with Sir 

 Norman Lockyer's 53037 and Prof. Campbell's 5303 '26 obtained 

 from the photographs of 1898. Shadow bands were seen a 

 minute and a half before totality, lying in a direction from 

 south-west to north-east and travelling from north-west to south- 

 east with a velocity comparable with that of a man walking, and at 

 a distance apart of 8 centimetres. The atmosphere was so clear 

 that the moon's disc was seen projected on the background of 

 the corona for two minutes after the last contact. During the 

 eclipse the thermometer in the shade fell 4° and that in the sun 

 8°. An interesting series of photographs is reproduced to show 

 the reduction of light at various phases of the eclipse, and copies 

 of the corona pictures are also included in the report. Seiior 

 Iniguez, to whom many foreign astronomers were indebted for 

 much valuable information relating to their expeditions, is to be 

 warmly congratulated on the admirable results of the efforts of 

 his own party. 



Opposition of Eros.-^A sixth circular has been issued by 

 M. Loewy from the Paris Observatory, containing ephemerides 

 of 81 fundamental stars selected from the region including the 

 trajectory of Eros during the period 1900 September-December, 



