298 



NA TURE 



[July 30, 1896 



The Royal Institution of Science, Letters, and Arts of Venice 

 oflcrs a prize of 3000 lire for the best essay on the alluvial 

 matter brought down from the Alps by one of the principal rivers 

 ofVenetia. The competition remains open till December 31, 

 1S96. 



An elTort is to be made to induce the Prince of Wales to place 

 himself at the head of the movement for celebrating at Bristol, 

 in June next year, the 400th anniversary of the discovery of 

 North America by John and Sebastian Cabot, who sailed from 

 Bristol. It is hoped that the foundation-stone of the memorial 

 will lie laid by the Prince of Wales simultaneously with one laid 

 in Canada. 



The International Congress of Applied Chemistry was opened 

 in Paris on Monday. Sixteen hundred delegates were present, 

 of whom six hundred were from other countries. M. Berthelot, 

 Perpetual Secretary of the Academy of Sciences, was elected 

 President.of the Congress, and delivered a powerful inaugural 

 address, in the course of which he dwelt particularly on the 

 relation between pure and applied science, the remarkable re- 

 sults obtained by the alliance of physics and chemistry, and the 

 beneficent part that science has played in the history of the 

 past three-quarters of a century. 



The Russian Geographical Society has awarded this year its 

 Constantine medal to M. A. Rykacheff, for his work in the 

 domain of physical geography. Beginning in the year 1874 

 with a work on the distribution of atmospheric pressure in 

 Russia, he continued to publish a series of researches on 

 the diurnal variations of pressure, the prevailing vvinds of the 

 Caspian and the White Seas, the tides in the atmosphere, the 

 freezing and thawing of the Russian rivers, the variations of 

 the levels of rivers in Middle Russia, in connection with varia- 

 tions in the amounts of rain and snow, the diurnal variations of 

 temperature over the tropical oceans, &c. A full list of M. A. 

 Rykacheff's works, mostly written in German and French, is 

 given in the yearly Report of the Society. The Count Lutke 

 medal has been awarded to Admiral Makaroff, for his work on 

 the temperature and density of water in the Northern Pacific, 

 based on the measurements made in 1SS6-89 on board the 

 Vityaz. His maps of the distribution of surface temperature in 

 August, and of temperature at a depth of 400 metres, are 



• especially worthy of notice. The Prjevalsky prize was awarded 

 to M. Berezovsky, for his explorations of the northern border- 

 lands of Tibet. A Prjevalsky medal was awarded to J. A. 

 Schmidt, for his twelve geodetical expeditions to different 

 parts of Central Asia and Siberia ; and one to Dr. H. 

 A. Frit-sche, for his magnetic measurements in China, Mon- 

 golia, Siberia, and Russia. Two small gold medals were 

 awarded to F. F. Mliller, for his magnetical work in East 

 Siberia ; and to A. A. Lebedint.seflf, for his researches into the 



■ chemical composition of water in the Black and Azov Seas. 

 Eighteen silver medals were awarded for various works of 

 lesser importance. 



A FULL description of the cell invented by Dr. W. W. 

 Jacques, for the production of electricity by the consumption of 

 carbon, is given in the July number of \.\ve. Engineering Magazine, 

 by Mr. G. H. Stockbridge. The apparatus consists of a pot 

 of pure iron surrounded by a suitable furnace and containing 

 ■caustic soda, in which hangs a rod or cylinder of carbon. The 

 carbon must be in such a state that will serve as a good con- 

 ductor of electricity. Gas, carbon, and charcoal are available 

 without special treatment ; but anthracite coal has to be baked 

 to give it the requisite conductivity, and bituminous coal needs, 

 for the same purpose, to have some of its hydrocarbons driven 



• off. Commercial caustic soda can be used without expelling 



■ the usual impurities. Air is forced through the caustic soda by 



NO. 1396, VOL. 54] 



means of an air-pump. To set the cell in operation the furnace 

 and its enclosed generator containing the caustic soda is brought 

 to a temperature of 400' to 500" C, and the air-pump is put in 

 action. The caustic soda takes up oxygen from the air, and 

 releases it at the carbon. The carbon is attacked by the oxygen, 

 and suffers a gradual consumption as long as the operation 

 continues, an electric current being produced as a result of the 

 action, the poles being the iron pot and the carbon rod. Some 

 electricians say the current is only a thermo-electric one. The 

 Qell is said to have an efficiency of eighty-five or ninety per cent. 

 This efficiency does not, however, take into account the expendi- 

 ture of heat for maintaining the cell at a suitable temperature, 

 or of the power used in running the air-pump which supplies 

 it with oxygen. Dr. Jacques' cell is an interesting addition to 

 the list of others devised to obtain electricity as a direct result 

 of the consumption of carbon ; but whether it will become of 

 practical value, cannot yet be decided. 



It seems as if the Boltzmann-Maxwell distribution of the 

 kinetic theory of gases is likely to become an everlasting bone 

 of contention. A short time ago we chronicled in these columns 

 an attack on Maxwell's original proof by M. Bertrand in the 

 Comptes rendns, on the ground that the proof assumed inde- 

 pendence of the frequencies of distribution of the velocity-com- 

 ponents of a molecule of the gas resolved in three directions at 

 right angles. This paper called forth a rejoinder from Prof. 

 Boltzmann, inviting M. Bertrand to examine Maxwell's later 

 proofs. M. Bertrand replied that he considered these even 

 wor.'^e than the first. Dr. Carlo del Lungo, writing in the Atti 

 del Lined in defence of the proof first objected to by M. Ber- 

 trand, now endeavours to prove that the assumed independence 

 of distribution of velocities is a necessary consequence of the 

 principles of conservation of momentum and of energy. It cer- 

 tainly seems impo.ssible to give a rigorous proof of the Boltzmann- 

 Maxwell distribution without making some assumption beyond 

 the ordinary principles of pure dynamics \e.g. the assumption 

 that the only intermolecular forces are those due to impact). 

 But Dr. del Lungo also upholds the view that the general evi- 

 dence in favour of the law lies in the fact that the distribution in 

 question satisfies so many conditions which are not satisfied by 

 any other distribution, and which represent more or less closely 

 the phenomena present in gases. 



Dr. a. Lampa, working in the laboratory of Prof. Franz 

 Exner, has determined the refractive indices of a number of 

 substances for electric waves of very small length. The experi- 

 ments, which form the subject of a communication to the Wiener 

 Sitzwigsberichle, were made with electromagnetic radiations of 

 8 mm. wave-length ; this number being ascertained both from 

 the dimensions of the excitor and by difl'raction observations. 

 The wave-length in question corresponds to the frequency 

 N = 37 '500 X 10", and Dr. Lampa gives the following values 

 for the index « : Paraffin, f524; ebonite, 1739; crown glass, 

 2'38l ; flint glass, 2-899; sulphur, l-802; benzole, 1767; 

 glycerine, I '843 ; oil of turpentine, 1 782 ; oil of vaseline, I '626 ; 

 oil of almonds, 1734; absolute alcohol, 2 568; and distilled 

 water, 8 972. 



M. L.-.\. Marmier, of the Pasteur Institution, has com- 

 municated to the Societe Fran9aise de Physique the results of 

 an interesting series of experiments on the action of currents of 

 high frequency on microbian poisons. It had been previously 

 announced by MM. d'Arsonval and Charrin that such currents 

 affect these poisons to a considerable extent, and M. Marmier 

 has examined whether this modification is a new phenomenon, 

 or merely a secondary result of well-known effects of the 

 current. It is found that the alteration in question only occurs 

 when the liquids are allowed to become healed to a tempera- 

 ture which would alone suffice to modify the poisons. When 



