April 26, 1888] 



NATURE 



623 



neighbourhood of Cambridge, Mr. Marr on Advanced Physical 

 Geology, Mr. Roberts on the Crinoidea, 



The above are only a selection out of a long list. 



Mr. J. G. Adams, of Christ's College, has been appointed 

 Demonstrator of Pathology on Mr. RoUeston's resignation. 



SCIENTIFIC SERIALS. 



American Journal of Science, April. — The absolute wave- 

 length of light, by Louis Bell. The final results are here given 

 of the research partially reported in the yoitrnal (or March 1886. 

 Owing to the wide discrepancies in the value of this constant 

 as determined by various observ'ers and methods, the author 

 gives a brief historical summary of the subject, with a critical 

 discussion of the standards of length, methods, and apparatus 

 employed in the present investigation. The details of the ex- 

 perimental work, together with some remarks on the final results, 

 and some questions of theoretical and practical interest con- 

 nected with the work of recent experimenters in this field, are 

 reserved for a future number. — History of the changes in the 

 Mount Loa craters ; Part i, Kilauea (continued), by James D 

 Dana. Here are discussed questions connected with the ascen- 

 sive action in the conduit lavas, the effects of heat, the hydro- 

 static and other gravitational pressure. — The electromotive force 

 of magnetization, by Edward L. Nichols and William S. Franklin. 

 At the Ann Arbor meeting of the American Association for the 

 Advancement of Science the authors described some singular 

 modifications in the relation of iron to acids which occur when 

 the reaction takes place within the magnetic field. In the 

 present paper, which was read at the New York meeting of the 

 Association in 1887, they deal with the behaviour of iron when 

 that metal acts as one electrode in a voltaic circuit, and is at the 

 same time subjected to magnetization. — Notes on certain rare 

 copper minerals from Utah, by W. F. Hillebrand. A series of 

 rare copper ores, including olivenite, erinite, tyrolite (?), chalco- 

 phyllite, clinoclasite, mixite (?), and bronchantite, are here sub- 

 jected to careful chemical and physical examination. — The 

 Taconic system of Emmons, and the use of the name Taconic 

 in geological nomenclature (continued), by Chas. D. Walcott. 

 The main subject of this paper is the geology of the Taconic 

 area as known to Dr. Emmous, with a comparison of its area as 

 now known. As a result of this comparative study, the author 

 finds that the Lower Taconic is essentially a repetition of the 

 Lower Silurian (Ordovician) of the Champlain Valley, while the 

 Upper Taconic appears to be conformably subjacent to the 

 Stockbridge Limestone of the Lower Taconic, and to include 

 the Potsdam horizon at or near its upper portion. — Three 

 formations of the Middle Atlantic Slope (continued), by W. J. 

 McGee. This paper is occupied with the Appomattox forma- 

 tion, its character, and distribution. — W. Le Conte Stevens 

 describes a new lecture apparatus of an extremely simple 

 character for the demonstration of reflection and refraction 

 ])henomena. 



SOCIETIES AND ACADEMIES. 

 London. 



Royal Society, March 8. — "Further Observations on the 

 Electromotive Properties of the Electrical Organ of Torpedo 

 luarmorata," By Francis Gotch, Hon. M.A. Oxon., B.A., 

 IJ.Sc. London, M.R.C.S. Communicated by Prof. J. Burdon 

 Sanderson, F. R.S. 



In the present treatise the author details the results of further 

 observations as to the electromotive properties of the electrical 

 organ of Torpedo, the experiments being carried out in October, 

 1887, at th3 laboratory of the Societe Scientifique d'Arcachon. 



I, The first part of the work deals entirely with the phenomena 

 '" "irreciprocal conduction'' in the organ of Torpedo, as 

 cribed by du Bois-Reymond. 



From du Bois Reymond's experiments it would appear that 

 the organ possesses the remarkable property of conducting an 

 intense current of short duration, led lengthwise through its 

 columns, better when the current is directed from its ventral to 

 its dorsal surface than when directed the reverse way. The 

 former direction coincides with that of the current of the shock 

 of the organ, and is therefore termed by him " homodromous," 

 the latter, being opposite in direction, is termed "heterodromous. " 

 The evidence rests upon the value of the galvanometric deflections 

 obtained when both currents are allowed to traverse a strip of 

 organ and a galvanometric circuit. The deflections are markedly 



unequal, particularly when induced currents are used, the homo- 

 dromous effect being always much greater than the heterodromous. 

 The homodromous current must therefore either encounter less 

 resistance than the heterodromous, or its electromotive force 

 must be suddenly strengthened, and that of the heterodromous 

 current weakened, by the sudden establishment in the tissue of a 

 new source of electromotive energy. The first is the view taken 

 by Prof du Bois-Reymond. 



(i) The present rheotome experiments reveal (a) the new 

 fact that the passage of such intense currents of short duration 

 is always followed by an excitatory response (shock) in the tissue ;. 

 {b) that if the intense current due to this response is allowed to 

 affect the galvanometer as well as the induced or other exciting 

 current, then by obvious algebraic summation the homodromous 

 deflection must be much larger than the heterodromous ; (c) and 

 that when by means of a fast-moving rheotome the induction 

 shock only is allowed to affect the instrument, no irreciprocity is 

 found. 



The author therefore assumes that the phenomena of irreci- 

 procal conduction are in reality excitatory phenomena, the nature 

 of which, from the methods of investigation used, have not been 

 recognized. 



(2) The tiine relations of this response of the isolated strip 

 of the organ to direct stimulation by the traversing induction 

 shock are now for the first time investigated, by means of the 

 rheotome, and the influence of temperature and other conditions 

 upon these is shown by experimental evidence. 



II. The second part deals with entirely novel phenomena — 

 namely, the excitation of the organ by the current of its own 

 excitatory state. It is shown that in vigorous summer fish every 

 response of the whole or part of the organ to a single excitation 

 of its nerves is followed by a second response, due to the passage 

 through its own substance of the intense current of the first 

 response. In other words, the shock of the organ excites its own 

 nerve fibres and nerve endings, producing a feebler second shock, 

 which in a similar manner evolves a feebler third shock ; this a 

 fourth, and so on. 



The response of the isolated organ to nerve excitation is thus 

 multiple ; a primary, secondary, tertiary response following the 

 application to the nerve of a single stimulus. Since all these 

 responses produce currents similarly directed through the columns 

 of the organ, each column during its activity must reinforce by 

 its echoes the force of the primary explosion, both in its own. 

 substance and also in that of its neighbours. 



Linnean Society, April 5. — Mr. W. Carruthers, F.R.S. ,. 

 President, in the chair. — Amongst the exhibitions of the evening 

 Mr. D. Morris (Kew) showed a curious native bracelet from 

 Martinique. Although formed apparently of seeds, or beads of 

 wood, or bone, its real composition had puzzled both botanists 

 and zoologists, and until microscopically examined could not be 

 determined. — Mr. J. G. Baker, F.R.S., exhibited a series of 

 specimens of Adiantum Fergnsoni and Capillis Veneris, and 

 offered some remarks upon their specific and varietal characters. 

 — Mr. J. E. Harting exhibited a specimen of a rare British 

 animal, the pine-marten, which had been trapped in Cumberland ; 

 and made some observations on the present distribution of the 

 species in the British Islands. — Mr. Clement Reid exhibited a 

 series of fruits and seeds obtained by Mr. J. Bennie from inter- 

 glacial deposits near Edinburgh, affording evidence of a colder 

 climate formerly than that now prevailing in the Lowlands of 

 Scotland. — Mr. F. Crisp exhibited some fragmentary remains of 

 a wild goose shot in Somersetshire, which had been reported as 

 the lesser whitefronted goose (Anser erythropns, Linn.), but 

 which was apparently an immature specimen of Anser albifrons, 

 Scopoli. — In the absence of the author, a paper by Mr. A. W. 

 Waters, on some ovicells of the Cyclostpmatous Bryozoa, was read 

 by the Zoological Secretary, Mr. W. Percy Sladen ; and after an 

 interesting discussion, the meeting adjourned. 



Chemical Society, March 28. — Annual General Meeting. — 

 Mr. W, Crookes, F. R.S., in the chair.— The President de- 

 livered an address on which we have already commented. 

 — The following Officers and Council were elected for 

 the ensuing session : — President : Mr. W. Crookes, F.R.S. 

 Vice-Presidents who have filled the office of President : Sir 

 F A. Abel, F.R.S. ; Dr. Warren de la Rue, F.R.S. ; 

 Dr. E. Frankland, F.R.S.; Dr. J. II. Gilbert, F.R.S.; 

 Dr. J. H. Gladstone, F.R.S. ; Dr. A. W. Hofmann, F.R.S. ;. 

 Dr. H. Miiller, F.R.S. ; Prof. Odling, F.R.S. ; Dr. W. H. 

 Perkin, F.R.S. ; Sir Lyon Playfair, I. R.S- ; Sir H. E. Roscoe» 



