262 



NA TURE 



[July 14, 1887 



George W. Card. Mining (ist Class) : John W. Sharwood, 

 Arthur M. M. Cooke. (2nd Class) : Caesar Bello, John Leech- 

 man, Andres Franchy, John H. Grant. 



SCIENTIFIC SERIALS. 



American yournal of Mathematics, vol. ix. No. 4 (Baltimore, 

 June 1887). — The number opens with a further instalment of 

 Prof. Sylvester's lectures on the "Theory of Reciprocants " 

 (pp. 297-352), which grow in interest as we approach their 

 close — promised in a subsequent number. Lectures xxv. to 

 xxxii. are reported as before by Mr. Hammond, and are 

 accompanied by the lecturer's notes. — M. Maurice d'Ocagne 

 (pp. 354-80) in a paper "Sur une Classe de Nombres re- 

 marquables," discusses properties of the numbers symbolically 

 represented by K„/. Form a table of squares, as in the case of 

 Pascal's arithmetical triangle, putting in the top left corner K, 

 and in the vertical and horizontal lines the successive numbers 

 I, 2, 3 . . . The K-numbers will then be, first row i, second 

 row, I I, third row 131, fourth row, i 7 6 i, fifth row, i 15 25 

 10 I, and so on ; the law of formation being, " Multiply the 

 number of the/th column of the q\\\ row by the number of the 

 column, and add to the result the number in the/- ith column 

 of the ^th row to get the number in the /th column of the 

 ^+ Ith row " : thus, in the above, 15 = 27 + i, 25 = 3*6 + 7, 

 10 = 4"i + 6. These numbers, like those of Bernoulli and Euler, 

 frequently occur in analysis. Many curious results are obtained. 

 — We next have " Extraits de Deux Lettres addressees a M. 

 Craig par M. Hermite " (pp. 381-88). These notes are upon a 

 definite integral formula of Fourier, upon a formula due to Gauss, 

 and upon a formula first given by Weierstrass (an expression for 

 the sine by a product of prime factors). — The volume closes 

 with a notelet by Prof. Franklin, entitled "Two Proofs of 

 Cauchy's Theorem." 



Rivista Scientifico-Ijidtistriale, April 30. — Recent progress in 

 the theory of the microscope, by Dr. Aser Poli. Reference is 

 made more especially to the labours of Abbe, Helmholtz, Crisp, 

 and others, which have been either originally published or re- 

 produced in the Journal of the London Royal Microscopical 

 Society during the last ten years. — On the electric conductivity 

 of gases and vapours, by Prof. Giovanni Luvini. This is a reply 

 to Prof. Edlund, of Stockholm, who has recently urged several 

 arguments against the author's views regarding the non-conduc- 

 tivity of gases and vapours. These arguments are examined in 

 detail, and it is shown generally that, being mainly based on 

 theoretic grounds or gratuitous assertions, they cannot affect 

 the conclusions to which the author has been led by carefully 

 conducted experirnents. — Celestine of Montecchio Maggiore, by 

 G. Bettanini. Preparatory to a complete study of this mineral, 

 a brief • description is here given of its crystalline forms and 

 general physical properties. Its specific gravity is shown to be 

 3 '965 at a temperature of 14° C. 



BiiUetin de I'Academie Royale de Belgiqjie, May. — A new rep' 

 tile discovered in the Aix-la-Chapelle district, by the Abbe G. 

 Smets. Considerable interest attaches to this discovery recently 

 made in a sandpit at Moresnet, a comparison with the Dino- 

 saurians brought to light in the chalk formations of the New 

 World showing that it is a carapaced Hadrosaurian, the first 

 representative of this family yet found in the eastern hemisphere. 

 — On the electrical phenomena of the excitatory process in the 

 heart of the dog, by Leon Fredericq. This elaborate paper is 

 introduced by an historical summary, from the discovery of the 

 negative variation of the heart of the frog by KoUiker and H. 

 Mliller down to the recent studies of Sanderson and Page, with 

 an account of the stroboscopic method employed by Marlins to 

 demonstrate the simple nature of the electric variation of the 

 heart in the dog and rabbit. This is followed by a full descrip- 

 tion of the apparatus employed and experiments made by the 

 author, who has investigated the subject by means of an electro- 

 meter modelled on that described by Loven. A detailed account 

 is added of the results of these researches, illustrated by a series 

 of photographic diagrams. — The solar eclipse of October 29, 

 1886, observed on the Congo, by A. Merlon. These observa- 

 tions were taken with great care in 3° 7' S. latitude above the 

 Congo-Kassai confluence to the north of Kwamouth. By means 

 of the data obtained and here supplied, the longitude of the 

 point of observation may now be accurately determined. The 

 instruments used were Abbadie's theodolite, Leroy's chronometer, 

 and Fortin's barometer. 



Rendicotiti del Reale Istituto Lombardo, June. — On the sulphate 

 of copper, as a remedy against the mildew of the grape-vine, by 

 Prof. E. Pollacci. A crucial chemical experiment is described, 

 showing that the sulphate of copper cannot pass from the grape 

 to the wine except in the minutest quantities. Some critical 

 remarks are added on various other remedies recently proposed 

 against diseases of the vine. 



SOCIETIES AND ACADEMIES. 

 London. 



Royal Society, June 16. — "The Electromotive Properties 

 of the Electrical Organ of Torpedo marmorata. " By Francis 

 Gotch, B. A., B.Sc. London, M.A. Oxon. Communicated by 

 Prof. Burdon Sanderson, F.R. S. 



After an introduction, in which the author sets forth the 

 present state of knowledge with reference to the electromotive 

 properties of the electrical organ of Torpedo, he gives an account 

 of his own experimental investigations in three sections. 



The first section relates to the nature of the changes produced 

 in the electrical organ by mechanical injury and by beat, and 

 the relation of these changes to those which manifest themselves 

 under similar conditions in muscle and nerve, a subject which 

 has not hitherto been inquired into. 



In the second, the duration and the character of the response 

 of the electrical organ to stimulation of its nerve are investigated 

 for the first time by means of the rheotome and galvanometer. 



In the experiments which are recorded in the third section, 

 the author has entered on the examination of the after-effects 

 which are produced in the organ by the passage through it of 

 voltaic or induction currents, a subject which has been recently 

 investigated by Du Bois-Reymond. 



The author is led by his experiments to believe that the 

 physiological effects produced in the organ by injury, by the 

 passage of currents, and by the stimulation of the electrical 

 nerve, are, notwithstanding that they differ so widely from each 

 other in distribution, duration, and intensitv, all phenomena of 

 excitation. [ 



Physical Society, June 25. — Mr. Shelford Bidwell, F.R.S 

 Vice-President, in the chair. — The following communicatiti: 

 were read : — Note on magnetic resistance, by Prof. W. 1 

 Ayrton, F.R.S. and Prof. J. Perry, F.R.S. In the spring 

 1886 the authors made experiments on the magnetic inducti 

 through horse-shoe electro-magnets when excited by consta 

 currents. The inductions through different armatures and .n 

 spaces were also measured. The results show that for smr; 

 exciting powers the law of parallel resistances is true f 

 magnetism, taking leakage into account. From experimeiv 

 made with two electro-magnets, the poles of which were plac> 

 at different distances apart, the authors conclude that the ma. 

 netic resistance of air is proportional to length, or to length pi 

 a constant. A note on magnetic resistance was read befo: 

 the Society on March 12, 1887, by the same authors, describii 

 experiments on two iron rings, one whole and the other divide 

 by a radial saw-cut. Since then the experiments have been ri 

 peated with great care by Colonel Swinton and Mr. Sorenson, > 

 the Central Institution. The resulting curves agree with the- 

 previously obtained. On measuring the air space it was foun 

 considerably less than estimated, and the magnetic resistance c 

 air relative to iron (assuming no "surface resistance") comt 

 about 1500. Experiments made with different air spaces t( 

 gether with the above seem to show a considerable "surfac 

 resistance." Prof S. P. Thompson thought dynamo-make 

 had evidence of such "surface resistance" from the care exe 

 cised in avoiding joints in the magnetic circuit wherever possibl 

 and Mr. Bosanquet mentioned some experiments he had recent 

 made on the resistance of joints during the various stages 

 fitting. The changes of resistance are very large, and 1 

 concludes that, however good the fit, it is not possible 

 reduce the surface resistance to a negligible quantity. — C 

 sounding coils, by Prof. W. Stroud and Mr. J. Wertheimt 

 The paper describes experiments on coils and helices 

 wire which emit sounds when variable electric currents a 

 passed through them. The pitch depends on the frequen' 

 of the current variations. The authors believe the soun 

 due to the attractions of adjacent parts of the wire whii 

 cause shortenings and lengthenings as the current increases 

 decreases. To prove this, two identical coils were made, ai 



