May 3, 1 906] 



NA TUKE 



23 



I'he collection was accompanied by natural history notes 

 and by a series of beautifully executed water-colour draw- 

 ings. Forty species of fresh-water fishes were now known 

 from the island ; these were enumerated in the paper, and 

 four of them described as now to science. — The collection 

 of Alcyonarians made by Mr. Cyril Crossland at Zanzibar 

 in 1901-2 ; Prof. J. A. Thomson and W. D. Henderson. 

 Specimens of sixty-five species or varieties were contained 

 ir\ the collection, of which twenty-seven were described as 

 new. — Cyclopia in osseous fishes, as observed in .several 

 advanced trout embryos : Dr. J. K. Gemmill. A detailed 

 account of the anatomy of the specimens was given, and 

 a comparison made with Cyclopia in mammals. The 

 author's views were also put forward regarding the mode 

 of origin of this condition in fishes. — Cases of super- 

 numerary eyes, and local deficiency and re-duplication of 

 the notochord, in trout embryos : Dr. Gemmill. — Descrip- 

 tions of three new varieties of butterflies of the genus 

 Heliconius : P. I. Lathy. 



Faraday Society, April 10. — Prof. A. "K. Huntington 

 in tile chair. — Electrothermics of iron and steel : C. A. 

 Keller. The author deals with the present position of his 

 processes ; he describes the electrical steel plant which 

 Messrs. J. Holtzer and Co. have just installed in their 

 works at Unieux (Loire). This is a 1500 h.p. plant, and 

 will utilise in a single furnace the current from a 20,000- 

 ampere Westinghouse alternator. The furnace, which rests 

 on a steel cradle and can be tilted, weighs about 50,000 

 kilos. ; the various mechanical and electrical controls are 

 obtained by hydraulic motors. The steel obtained from a 

 .Siemens-Martin furnace will be run into the electric 

 furnace immediately after the oxidising melt, and for the 

 remaining operations of deoxidising and refining the 

 lurrent exclusively will be used. — Note on the rotating 

 electric steel furnace in the Artillery Construction Works, 

 Turin : Ernesto Stassano. The furnace described and 

 illustrated in the paper is being installed by the " Forni 

 Termoelettrici Stassano " Company for the Italian War 

 Office. It is of the author's well-known arc type, and 

 absorbs 140 kilowatts, yielding 2400 kilos, of steel in 

 iwenty-four hours. The current is a rotary one with So 

 volts between each phase. The consumption of electrodes is 

 less than 5 kilos, per ton of steel, and the cost of renewing 

 the refractory covering of the furnace 10 francs per ton 

 of metal made. The furnace is principally used for re- 

 fining pig-iron and smelting scrap. The product ordinarily 

 made is used for artillery projectiles. — Note on recent de- 

 velopments in the Gin electric steel furnace : Gustave Gin, 

 The author's canal-type of furnace is now installed at the 

 Plettenberg Works, Westphalia, of which illustrations arc 

 given in the paper, but it is not stated which particular 

 type of furnace has there been experimented with. The 

 following types are described : — (i) furnace with canals 

 .and chambers ; (2) combination furnace : (3) induction 

 furnace. — Notes on the cleaning of work by means of the 

 electric current : H. S. Coleman. The work to be cleaned 

 (usually preparatory to electro-plating) is suspended in a 

 hot solution of equal quantities of brown Montreal potash 

 and sodium hydrate contained in a wrought-iron tank. 

 The work and the tank are connected to a dynamo, and the 

 tank used as the anode for five to ten minutes, the voltage 

 being about 2-5. The current is then reversed for a short 

 time, until the surface of the work is clear and bright. 

 The operation is repeated as many times as may be 

 necessary. 



Royal Meteorological Society, April iS. — Mr. R. 

 Bentley, president, in the chair. — Some so-called vagaries 

 of lightning reproduced experimentally : A. Hands. The 

 author, in the course of an extended investigation into the 

 effects of lightning, has come across many cases that have 

 been called vagaries, but which on a close inspection have 

 proved to be extraordinary only in the erroneous way in 

 which they were described, and, had thev been correctly 

 reported, would have appeared perfectly consistent with 

 preconceived ideas — in fact, could have been foretold in 

 every case if the conditions that led to those effects had 

 been known before the events occurred. The author re- 

 produced experimentally several so-called vagaries of light- 

 ning, showing by means of rough models the conditions 

 under which they occurred. — The value of a projected 



NO. 1905, VOL. 74] 



image of the sun for meteorological study : Miss C. O. 

 Stevens. By this method it has been ascertained that 

 where the direction of movement of the atmosphere is 

 tangential to the limb of the sun, the phenomenon of 

 " boiling " displays a coursing or rippling character, and 

 that where it is perpendicular to the limb of the sun, the 

 character of the movements of distortion is that of spring- 

 ing in and out of the area of the sun's image. Both these 

 elements of movement are continuous even in the absence 

 of all visible cloud, and it is possible, not only to detect, 

 but also to distinguish betw-een overlying invisible atmo- 

 spheric strata. 



Mathematical Society, April 26. — Prof. A. R. Forsyth, 

 president, and subsequently Prof. W. Burnside, vice-presi- 

 dent, in the chair. — Perpetuants and contra-perpetuants ; 

 Prof. E. B. Elliott. It is proposed to apply a method, 

 based on the use of symmetric functions and of certain 

 differential operators, to the discovery of complete systems 

 of perpetuants of given partial degrees in assigned sets of 

 coefficients, which shall be equivalent in their aggregate 

 to those which have been arrived at by the systematic 

 examination of symbolic products. Contra-perpetuants are 

 introduced in connection with Hermite's doctrine of re- 

 ciprocity between degree and extent in systems of semin- 

 variants when this doctrine is correlated with the theory 

 of perpetuants. — \ set of intervals about the rational 

 numbers : A. R. Richardson. \ definite construction is 

 given for associating a set of intervals with the rational 

 numbers, in such a way that all the rational numbers are 

 included in the intervals, and certain definite sets of 

 irrational numbers are excluded from all the intervals. — 

 Some theorems connected with Abel's theorem on the con- 

 tinuity of power series : G. H. Hardy. The paper deals 

 with the generalisation, for series of which the terms are 

 continuous functions of a variable, of certain well-known 

 theorems relating to power series. The convergence of 2a„ 

 is sufficient to secure the uniform convergence of 

 5a„/„(.v) in an interval in which all the functions y„(.v) 

 are continuous, and these functions diminish in value as 

 n increases ; a similar theorem holds also if 2<i„ diverges, 

 but is of the type which can be summed by averages. — 

 The canonical forms of the ternary sextic and quaternary 

 quartic : Prof. A. C. Dixon. The forms are the sums of 

 ten sixth, or fourth, powers, as the case may be. Pro- 

 cesses are given for carrying out the reductions to these 

 forms, and it is shown that in each case there are two 

 solutions. — The accuracy of interpolation by finite differ- 

 ences : W. F. Sheppard. The paper deals with the 

 relative accuracv of the ordinary advancing-difference 

 formula and the central-difference formulje in regard to 

 the two sources of error which arise (i) from omitting the 

 remainder in the series by which the values of a function 

 are calculated, (2) from the fact that tabulated values of a 

 function are only approximate. — The geometrical interpret- 

 ation of apolar binary forms : C. F. Russell. The paper 

 is concerned with geometrical constructions which may 

 be regarded as generalisations of the construction of the 

 fourth harmonic point of three given points in a definite 

 order. For two apolar forms of the same order, analogous 

 to two quadratic forms harmonically related, the construc- 

 tion is linear. — Two cubic curves in triangular relation : 

 Prof. F. Moriey. — The question of the existence of trans- 

 finite numbers : P. E. B. Jourdain, — .\ question in the 

 theory of aggregates : Prof. A. C. Dixon. 

 Paris. 



Academy of Sciences, April 17. — M. H. Poincare in the 

 chair. — The president announced the death of Prof. 

 Langley, correspondant of the academy. — The evaluation 

 of the foco-facial distances of microscopic objectives : L. 

 Malassez. A comparison of two experimental methods 

 with the results of a formula developed by the author in 

 previous papers. — Pure ferro-molybdenums : contribution to 

 the study of their constituents : Em. Vigouroux. Alloys 

 of iron and molybdenum containing varying proportions 

 of the two constituents were submitted to treatment either 

 with dilute hydrochloric acid or an acid solution of cuprous 

 chloride. The insoluble residues from fourteen separate 

 alloys were analysed, and the following four compounds of 

 iron and molvbdenum isolated in a pure state : — Fe,Mo, 

 FejMoj, FeMo, FeMo,. The physical and chemical proper- 



