May 24, 1900] 



NATURE 



93 



.>nd cuprous compounds. Wherever the formation of a molecule 

 out of its constiluent atoms leads to a considerable contraction 

 of volume, the molecular magnetism is increased, so that the 

 result may even be a paramagnetic compound. Where, on the 

 other hand, there is expansion, the diamagnetism increases. — 

 Energy of kathode rays, by W. Cady. The author discusses the 

 various methods of determining the energy of kathode rays. 

 The thermopile and the bolometer have undoubted advantages 

 as compared with the calorimeter, but it is necessary to know 

 how much of the energy incident upon them is reflected, and 

 how much energy is lost in the process of reflection. The 

 author bases his calculations upon the supposition that 40 per 

 cent, of the kathode energy is reflected, and that the amount of 

 energy lost during reflection is 30 per cent. — Electric arc 

 between metallic electrodes in nitrogen and hydrogen, by L. 

 Arons. The electromotive forces necessary to produce an arc 

 between metallic electrodes depends upon the nature of the 

 surrounding gas. In air, silver electrodes give a fine arc, but no 

 arc can be produced with them in nitrogen. Iron electrodes, 

 which require a high voltage in air, require only a very low 

 voltage in nitrogen. — Electrolytic records of electric currents, 

 by P. Gruetzner. The author gives details of the method of 

 recording alternating currents of high frequency with the aid of 

 iodine paper, and shows that for low voltages it offers decided 

 advantages over the dust-figure method. — Change of volume of 

 rubidium during fusion, by M. Eckardt. The fusing point of 

 rubidium is 37*80°. During melting, I gramme of rubidium 

 expands by o 01657 c.cm. 



Symons's Monthly Meteorological Magazine, May. — Meteoro- 

 logical extremes : wind-force. This is the third of a valuable 

 series of articles ; the first two referred to pressure and tempera- 

 ture. The difficulties are far greater than in the other cases, as 

 in determining wind-force observations no homogeneity exists 

 either as regards the instruments employed, or the units of the 

 various scales in which the results, either instrumental or esti- 

 mated, are expressed. The instrument most generally used is 

 Dr. Robinson's cup-anemometer, the few others being chiefly 

 ' ler's or Dine's pressure anemometers. In the velocity instru- 

 :Us the factor for obtaining the true velocity of the wind 

 lends upon the length of the arms and the size of the cups. 

 Until recently the factor used has been 3, but more recent 

 ; experiments have shown that the speed at the cups should be 

 multiplied by the factor 22, so that some very high velocities 

 fninierly recorded should be reduced by nearly one-third. 

 Among the highest velocities recorded in this country (reduced 

 by the new factor 2-2), we may mention a severe gale in the 

 I Irish Sea in January 1899, in which a rate of 90 miles per hour 

 i was recorded in one gust ; the maximum mean force for an hour 

 •^■< Fleetwood was 75 miles. The highest recorded velocity in a 

 was recorded by Dines's anemometer at Rousdon, in South 

 m, in March 1897, viz. at a rate of loi miles per hour. At 

 w.eenwich a pressure of 51^ lbs. on the square foot was recorded 

 Mil January 18, 1881, which is equivalent to a velocity of about 

 130 miles per hour, but there is good reason for believing that 

 I in strong winds the records of these pressure plate anemo- 

 I meters are occasionally much too high. It is still a moot ques- 

 I tion, what is the strongest force that the wind attains, and whether 

 the force in some of the gales which visit our exposed shores 

 from the Atlantic is much exceeded in tropical cyclones. 



Bollettino della Societa Sismologica Italiana, vol. v. 1899- 



I 1900, No. 7.— List of earthquakes observed in the East, and 



' especially in the Ottoman Empire, during the j ear 1896, by 



' Agamennone. An extract from a paper noticed in Naturf;, 



Ixi. p. 400. — The Etnean earthquake of May 14, 1898, by 



Kicco. The epicentre was at S. Maria di Licodia on the 



south-west slope of Etna, and the focus must have been shallow, 



for the shock was strong enough to damage many buildings near 



the centre of a small disturbed area. — Notices of earthquakes 



recorded in Italy (October ll-November 19, 1898), by A. Can- 



cani ; the most important being earthquakes in Sicily on 



November i, 2 and 3, Dalmatia on November 8, the Ionian Sea 



I on November 9, and distant earthquakes on October 12 and 



November 17. 

 I No. 8.— The Modena- Bologna earthquake of the night of 

 February 1-2, 1900, by G. Agamennone. A slight shock, with 

 a disturbed area of about 60,000 sq. km., but recorded by a 

 j, seismograph at Lubiana (330 km. from the epicentre).— On an 

 ji electrothermic phenomenon in electrical contacts with slight 

 I pressure, by A. Cancani.— Latian earthquake of July 19, 1899, 



^^' 1595. VOL. 62 J 



by A. Cancani, a paper noticed in Nature, vol. Ixi. p. 573. — 

 Notices of earthquakes recorded in Italy (November 21 -Decem- 

 ber 31, 1898), by A. Cancani, the most important being distant 

 earthquakes on December i and 3. — On a new form of multipli- 

 cation applicable to seismic movements and on a new seismo- 

 scope founded on the same, by G. Pericle. 



Bulletin de la Society des Natiiralistes de Moscoit, 1899, No. i. 

 — Meteorological observations at Moscow in 1898, by E. Leyst. — 

 On the development of green algues under conditions excluding 

 the assimilation of carbon-dioxide, by Dr. A. Artari. — On the 

 Hedysarutn species (15) found in European Russia, Crimea and 

 Caucasia, by B. Fedtschenko. — On the Hydrachnids of the neigh- 

 bourhood of Moscow, by A. Croneberg (plate). Forty-nine 

 species, several of which are new, are described. — On the 

 iron-ores {tiirjit) of the South Urals, by J. Samoiloflf. All 

 these articles, with the exception of the last one, are in German, 

 or contain German resumes. — Notes on Coleoptera of European 

 Russia and Caucasia, by A. Semenoff. 



Memoirs of the Mathematical Section Oj the Novorossian 

 {Odessa) Society of Naturalists, vol. xix. — Foundations of a 

 theory of analytical functions, by J. Timtchenko, continued 

 from vols., xii. and xvi. This part contains the history o£ 

 certain special questions, the discussion of which has mainly 

 contributed to the development of the theory of these functions. 



Memoirs of the Kazan Society of Naturalists, \o\%. xxxii. and 

 xxxiii. — Materials relative to the flora of the northern boundaries 

 of the black-earth region, by S. Griegorieff. — The corals of the 

 Devonian deposits in the Urals, by N. Bojartsen (one plate). 

 Filty-six species are enumerated, several of these, as also one 

 genus [Nicholsonia), being new. — On the saliva glands oi Peri- 

 plancta orientalis, by A. Lebedeflf (plate). — The Ranunculacea? 

 of Russian Turkestan, by Olga and Boris Fedtschenko. One 

 hundred and fifty-eight species are enumerated, forty-three species 

 being endemic, and thirty-eight species belonging to the Alpine 

 region. A suggestion for the determination of the Turkestan 

 species is given. All articles are summed up either in French 

 or in German. 



SOCIETIES AND ACADEMIES, 

 London. 



Royal Society, May 10.—" On Certain Properties of the 

 Alloys of Gold and Copper." By Prof. Sir W. C. Roberts- 

 Austen, K.C.B., F.R.S., and T. Kirke Rose, D.Sc. 



The alloys of gold and copper, which are of great industrial 

 importance owing to their use in coinage, have not been sub- 

 jected hitherto to systematic examination. It has been assumed 

 that they differ widely from the silver-copper series, which has 

 been studied from different points of view, but there is very 

 little evidence on which this view can be based. 



Examination with the aid of a thermo-couple and autographic 

 recorder shows that the freezing-point curve of the gold-copper 

 series consists of two branches setting out from the points of 

 solidification of the pure metals and meeting at a point, which - 

 is the freezing point of theeutectic. The eutectic contains about 

 82 per cent, of gold and 18 per cent, of copper, or about 60 atoms 

 of gold to 40 of copper, and solidifies at 905°, The general , 

 shape of the curve therefore resembles that of the silver-copper 

 series when the abscissas give the relative number of atoms. 



Under the microscope, alloys containing more than 82 per 

 cent, of gold show a minutely granular structure in which it is 

 not certain that two constituents can be distinguished. The 

 section of standard gold containing 91 "6 per cent, of gold bears 

 a close resemblance to that of standard silver prepared in the 

 same way. The alloy with 80 per cent, of gold shows the 

 characteristically- banded eutectic structure almost exclusively, 

 and the alloys with less gold consist of crystals of copper set ia 

 a matrix of the eutectic. 



Another point of similarity between the gold-copper and 

 silver-copper series is that both the eutectics are brittle and_ 

 show scarcely any extensibility ; they differ in these respect from, 

 most other eutectics. Analysis of various portions of ingots of 

 standard gold reveals the fact that liquation takes place as. 

 definitely as in standard silver, the difference in compositiork, 

 between the centre and the outside of similar ingots being, how- 

 ever, three or four times greater in standard silver than ia 

 standard gold. In the latter case, the centre contains from 

 o'3 to I'o part per 1000 less gold than the outside. 



