March 24. i«o«1 



NATURE 



503 



\ 



February 21 — Mr. F. Darwin in the chair. — On some diflfer- 

 ential equations in the theory of symmetric algebra, Prof. 

 Forsyth. — Discharge of electrification by ultra-violet light, E. 

 Rutherford. In this paper the general phenomena of conduc- 

 tion under ultra-violet light were considered, especially from the 

 point of view of the nature and velocity of the carrier of the 

 negative electrification. By directing a blast of air against a 

 plate on which ultra-violet light fell, it was shown that the 

 whole or portion of the carriers could be removed with the cur- 

 rent of air. The charged gas so obtained shows properties 

 similar to the charged gas obtained in Rontgen conduction. A 

 general method of determining the velocity of the carrier was 

 given. By its means the velocity of the carrier for air was found 

 to be about 1*4 cms per sec. for a potential gradient of one 

 volt per cm. The velocity of the carrier is independent of the 

 metal on which the light falls, but depends on the gas sur- 

 rounding the plates. The velocity of the carrier was found to 

 be inversely proportional to the pressure, a result which shows 

 the carrier is of molecular dimensions. The results of the ex- 

 periments are simply explained on the hypothesis that gaseous 

 ions are produced at the surface of the negatively electrified 

 plate. The theory previously advanced that the discharge was 

 due to the disintegration of metallic particles under the action of 

 ultra-violet light does not sufficiently explain the facts. — Rontgen 

 photographs of metallic alloys, C. T. Heycock and F. H. 

 Neville. The authors exhibited and described photographs 

 taken by means of the Rontgen rays through plates of alloy. 

 As the two metals forming the alloy possess different degrees of 

 transparency to these rays, the photographs show the separation 

 of the metals that has taken place during the solidification of the 

 alloy. For example, alloys of gold and sodium containing less 

 than 30 per cent, of gold are seen to consist of well-developed, 

 very transparent crystals, which must be pure, or nearly pure, 

 sodium, imbedded in a mother substance which solidified last, 

 and which, from its comparative opacity, evidently contains the 

 gold. On the other hand, alloys containing more gold show 

 very opaque needles of gold imbedded in a less opaque mother 

 substance. This mother substance was the same as that in the 

 first-mentioned alloy ; it solidified after the needles of gold had 

 been formed. Photographs of alloys of aluminium and gold, 

 and of aluminium and copper, were shown, which exhibited 

 similar phenomena, fhe crystals of aluminium in the alloy 

 with copper were perfect rectangular crosses several millimetres 

 in diameter. The gold-aluminium alloys showed a precipitate 

 of Roberts- Austen's compound of the formula AuAl^ ; the 

 crystals were well-marked tubes and octahedra. 



Manchester. 



Literary and Philosophical Society, March 8. — Mr. 

 J. Cosmo Melvill, President, in the chair. — The President 

 announced that the title of the Wilde Lecture to be delivered 

 by Prof. Michael Foster on March 29, would be "On the 

 physical meaning of psychical events." — Mr. Thomas Thorp 

 exhibited some celluloid films taken from Rowland's gratings 

 of 14,438 lines to the inch. — " On the velocity of sound in a 

 tube, as affected by the elasticity of the walls," by Prof. H. 

 Lamb, F. R.S. The paper consisted in an application of the 

 known theory of the vibrations of thin cylindrical shells to the 

 calculation of the velocity of sound in a tube filled with liquid. 

 This subject has already been treated by Korteweg, but the 

 author's method is somewhat different, and one or two collateral 

 results of interest are obtained. The paper included, further, 

 an approximate investigation of the effect in a thick tube. 



Edinburgh. 

 Royal Society, January 31.— Prof. Chrystal in the chair. — 

 An obituary notice of the late Edmund Chisholm Batten was 

 read.— Dr. J. K. Talmage, a delegate to the Geological Con- 

 gress of 1897, gave in a report of the meetings.— Papers by Dr. 

 Thomas Muir, on the relations between the co-axial minors of 

 a determinant of the fourth order, and by Prof. Nanson on the 

 Ellipse-Glissette elimination problem, being purely technical, 

 were laid on the table.— Mr. W. L. Calderwood read a paper 

 on the migratory movements of Salmonidae during the spawning 

 season. After distinguishing between spring and summer runs 

 of fish and calling attention to the dissimilarity between such 

 runs and the autumn runs to the head waters for the express 

 purpose of spawning, the author showed that these last runs 

 could alone be considered as analogous to the runs in connection 

 with the spawning habit of Cliipea allosa, C. finta, or Petromyzon 



NO. 1482, VOL. 57] 



niarinus. As to the conditions of water flow which seemed 

 most favourable for Salmonidie entering a tributary from a main 

 river, Mr. Calderwood submitted several tables of data collected 

 by daily observations in the spawning season of 1896-97. The 

 results showed that most fish entered the particular tributary 

 under consideration when the water was in quarter-flood ; that 

 temperature had apparently no influence upon the runs of fish ; 

 that a limited number of fish ascended during normal flow of 

 the stream ;. that the sea trout commenced to ascend later than 

 salmon, but remained a much shorter period, completing their 

 spawning two months before the last salmon redd was observed. 

 The author exhibited a diagram-chart of the spawning grounds, 

 showing the distribution of salmon and sea trout redds, and the 

 dates on which the redds were constructed. 



Paris. 

 Academy of Sciences, March 14. — M. Wolf in the 

 chair. — Chemical actions of the silent discharge. Nitrogen com - 

 pounds in presence of free nitrogen, by M. Berthelot. A con- 

 tinuation of similar work published in preceding numbers of the 

 Comptes rendiis. The substances dealt with included methyl- 

 amine, dimethylamine, ethylamine. propylamine, isopropyl- 

 amine, allylamine, aniline, methylaniline, benzylamine, toluidine, 

 pyridine, piperidine, ethylenediamine, propylenediamine, 

 phenylenediamine, benzidine, nicotine, acetamide, thiourea, 

 acetonitrile, benzonitrile, aldoxime, phenylhydrazine, some 

 nitro-derivatives, pyrol and indol. — On the estimation of 

 carbon monoxide diluted with large quantities of air, by 

 M. Armand Gautier. Remarks on the use of iodic anhydride 

 for the estimation of minute quantities of carbonic oxide 

 (l in 20,000). The reaction is complete at 60°, the iodine 

 being collected upon a roll of reduced copper and weighed. 

 Better results are obtained by determining the carbon dioxide 

 produced. Acetylene also reacts with iodic anhydride, 

 and ethylene, although not reacting itself at 60°, possesses 

 the peculiar property of completely preventing the oxidation of 

 carbon monoxide. — On the importance of sugar considered as a 

 food ; new demonstration of the superior nutritive value of 

 sugar compared with that of fat, taking the respective thermo- 

 genic values of the two foods into account, by M. A. Chauveau. 

 Two series of experiments were carried out upon the same 

 animal (a dog), one with a sugar and the other with a fatty 

 diet ; the results showed that sugar possesses great advantage 

 over the dynamically equivalent proportion of fat. It is, then, 

 erroneous to consider the nutritive value of a food as measured 

 by its heat of combustion. — The development of the sponges, 

 by M. Edmond Perrier. A controversial reply to a paper on 

 the same subject by M. Yves Delage. — The expedition to 

 Greenland of the Geographical Society of Berlin, by M. Marcel 

 Bertrand. The present note deals only with that part of the 

 work which concerns the structure of the ice and the movements 

 of glaciers. The explanation given for the latter, which 

 satisfactorily accounts for all the observed facts, is practically 

 identical with that proposed by Thomsen, the arguments now 

 added by M. de Drylgaski rendering these views more precise. 

 — On the theory of numbers, by M. H. Laurent. — Integral 

 invariants and optics, by M. Hadamard. — On the laws of reci- 

 procity, by M. X. Stouff. — On the transformation of Abelian 

 functions, by M. G. Humbert.— The energy of an electrified 

 system, considered as distributed in the dielectric, by MM. H. 

 Pellat and P. Sacerdote. — On the electric conductivity of thin 

 plates of silver, by M. G. Vincent. The films were deposited 

 on glass, and the thickness, which varied between 38/^ and 

 170/U, measured by the methods of Wiener and Fizeau. The 

 results of the measurements fell practically upon a straight line 

 for thicknesses down to 50^4, below which an inflexion of the 

 line took place. This critical thickness agrees well with the 

 number obtained by Quincke in his capillarity experiments.^ 

 Some properties of electric discharges produced in a mag- 

 netic field. Assimilation to the Zeeman phenomenon, by 

 M. Andre Broca. The hypothesis of the existence of 

 ions in incandescent gases is sufficient to coordinate 

 all known facts relating to the radiation of incandescent 

 gases and also those relating to the electric discharge in 

 gaseous media. — On the barometric formula, by M. Alfred 

 Angot. The assumptions necessary for the accuracy of the 

 Laplace formula are not strictly fulfilled in actual practice, so 

 that the heights of an experimental balloon determined by the 

 barometer and by triangulation respectively, may differ by as 

 much as 500 metres in a height of 11,000 metres. —On the 



