382 



NA TURE 



[February 17, 1898 



rise of temperature was greater. Knowing the heat of com- 

 bustion of hydrogen, a simple calculation gave the heat evolved 

 by the exothermic change in the mineral. 



Various questions are raised by the behaviour of this interest- 

 ing mineral. Its evolution of heat, accompanying its parting 

 with helium, suggest the idea that it is a true endothermic 

 compound of helium. Had its density, as is the case with 

 alumina, and with other oxides which rise spontaneously in 

 temperature when heated, increased instead of decreased, the 

 evolution of heat might justly have been ascribed to polymerisa- 

 tion. But an evolution of heat, accompanied by a fall in 

 density, leads to the conjecture that the loss of energy is the 

 result of the loss of helium ; and that, conversely, the formation 

 of the compound must have been concurrent with a gain of 

 energy. That the helium is actually in combination, and not 

 retained in pores in the mineral, is evinced by there being no 

 pores in which the helium might be imprisoned. Surface- 

 absorption is equally out of the question, for the mineral is 

 compact. The only remaining possibility is that the helium is 

 in chemical combination. And if this is true, then the 

 compound must be an endothermic one. 



There is one other substance at least which decreases in 

 density, while it evolves heat ; that substance is water, in 

 changing into ice. The effect of compressing ice is to lower its 

 melting point, and at the same time to reduce its heat of fusion. 

 At a sufficiently high pressure there would be a continuous 

 transition from ice to water, no heat change taking place 

 during the transition. Matters would be in a similar condition 

 to those which accompany the change of a liquid into gas at the 

 critical temperature ; the smallest alteration of temperature 

 would be enough to bring about the change. In speculating on 

 the origin of such a remarkable compound, is it not allowable 

 to guess that it represents a condition of our earth realised only 

 before solidification had set in ? That these minerals, contain- 

 ing the rare elements, represent a portion of the interior of our 

 planet ; and that under the enormous pressure obtaining at the 

 centre, combination with helium was an exothermic event ; and 

 that such compounds, having by some unexplained accident 

 come to the surface of the globe, where they are no longer ex- 

 posed to such pressure, they have, in consequence of the change, 

 become endothermic? The frequency of the helium spectrum 

 in the stars, and its presence in the sun, makes it less improbable 

 that some such explanation may lie not far from the truth. 



February 3. — " Note on the Experimental Junction of the 

 Vagus Nerve with the Cells of the Superior Cervical Ganglion." 

 By Dr. J. N. Langley, F.R.S., Fellow of Trinity College, 

 Cambridge. 



The author concludes from his experiments that there is 

 no essential difference between the efferent "visceral" or 

 "involuntary" nerve fibres, whether they leave the central 

 nervous system by way of the cranial nerves, by way of the 

 sacral nerves, or by way of the spinal nerves to the sympathetic 

 system. All of these fibres he takes to be pre-ganglionic fibres. 

 And he thinks that any pre-ganglionic fibre is capable, in 

 proper conditions, of becoming connected with any nerve cell 

 with which a pre-ganglionic fibre is normally connected ; al- 

 though apparently this connection does not take place with 

 equal readiness in all cases On the whole it appears that 

 the functions exercised, both by pre-ganglionic and by post- 

 ganglionic fibres, depend less upon physiological differences 

 than upon the connections which they have an opportunity of 

 making during the development of the nervous system and of 

 the other tissues of the body. 



Physical Society, Annual General Meeting, February 11, 

 1898.— Mr. Shelford Bidwell, President, in the chair. The 

 Report of the Council was read by Mr. Elder. Dr. Atkinson 

 then presented the Treasurer's Report, and informed the Society 

 of the improved condition of its finances. The difficulties of 

 the previous year had arisen from the expenses incurred by the 

 publication of abstracts of current scientific literature ; those 

 difficulties had been surmounted without drawing upon the 

 reserve fund. Very few Fellows had objected to the increase of 

 subscription. In acknowledgment and appreciation of the 

 abstracts, now presented to all Fellows, many of the original 

 life-members had lately made additional voluntary donations to 

 the funds of the Society, thus sharing with new Fellows the 

 extra outlay involved by the abstracts. It was to be hoped that 

 all life-members would adopt this course, more especially as the 

 scope of scientific literature covered by the abstracts was npw 



NO. T477, VOL. 57] 



being extended to British as well as to foreign sources. Votes 

 of thanks were passed to the Council, the officers, and to the 

 Council of the Chemical Society for the use of their rooms at 

 Burlington House. Two Honorary Fellows were unanimously 

 elected by ballot, i.e. Riccardo Felici, professor in the University 

 of Pisa ; and Emilio Villari, professor in the University of 

 Naples. Council and officers for the forthcoming year were 

 elected as follows. President : Mr. Shelford Bidwell. Vice- 

 Presidents (who have filled the office of President) : Dr. J. H. 

 Gladstone, Prof. G. C. Foster, Prof. W. G. Adams, The Lord 

 Kelvin, Prof. R. B. Clifton, Prof. A. W. Reinold, Prof. W. E. 

 Ayrton, Prof. G. F. Fitzgerald, Prof. A. W. Rucker, Captain 

 W. de W. Abney. Vice-Presidents : Prof. C. Vernon Boys, 

 Major-General E. R. Festing, Mr. G. Griffith, Prof. J. Perry. 

 Secretary : Mr. H. M. Elder, 50 City Road, E.C. Foreign 

 Secretary : Prof. S. P. Thompson. Treasurer : Dr. E. Atkin- 

 son. Librarian : Mr. W. Watson. Other Members of Council : 

 Prof. H. E. Armstrong, Mr. Walter Baily, Mr. L. Clark, Dr. 

 A. H. Fison, Mr. R. T. Glazebrook, Prof. A. Gray, Prof. J. 

 Viriamu Jones, Mr. S. Lupton, Prof. G. M. Minchin, Mr. J. 

 Walker. — The President then read an address in which 

 the aims and history of the Physical Society were outlined. 

 (An abstract of this address is published in the present 

 issue, p. 378.) Prof. Rucker said that among the new 

 and useful departures lately made by the Physical Society 

 the institution of a presidential address was particularly worthy 

 of notice ; it was very desirable, from time to time, to hear 

 a summary of what had been achieved during the year ; it 

 was also desirable that the objects of the Society should be, 

 from time to time, definitely stated ; this departure had been 

 fully justified by the address of Mr. Shelford Bidwell. — A paper 

 by Mr. G. H. Bryan on electro-magnetic induction in plane, 

 cylindrical and spherical current sheets, and its representation 

 by moving trails of images, was read by Mr. Elder. The phe- 

 nomena of induction in a cylindrical conducting sheet in a two- 

 dimensional field, and of induction in a sphericaljsheet in any field 

 due to the generation or motion of poles, magnets, or currents, in 

 the presence of the sheet, can be represented by moving trails of 

 images which are but slightly more complicated than the well- 

 known trails of images in a plane sheet. The images, representing 

 the potentials of the induced currents on the two sides, start 

 from the source of disturbance and its inverse point, and move 

 normally away from the surface of the sphere and cylinder, 

 with velocity varying directly as the disturbance. At the surface 

 of the sheet this velocity becomes equal to the corresponding 

 velocity for a plane sheet. The images are in most cases similar 

 in nature to the inducing source of disturbance, and their in- 

 tensities are found, in every case, to vary as a power of the dis- 

 tance from the centre. The images due to the sudden genera- 

 tion of a magnetic pole in the presence of a spherical sheet 

 are, however, analogous to the hydro-dynamical image of a 

 source in a sphere. Dr. S. P. Thompson said the method and 

 the results obtained would find useful application in the solution of 

 many allied problems. — The President proposed a vote of thanks 

 to the author ; the meeting was then adjourned until Saturday, 

 February 26, on which occasion the Physical Society will visit 

 Eton College. [Fellows are informed that a train leaves Pad- 

 dington for Windsor at 2.25 p.m. This arrives in time for the 

 meeting, which is at 4 p.m.] 



Zoological Society, February i. — Dr. St. George Mivart, 



F. R.S., Vice-President, in the chair. — Mr. Oldfield Thomas 

 exhibited the skull of a giraffe from the Niger region, which 

 had been shot by the late Lieut. R. H. McCorquodale, and pre- 

 sented to the British Museum by his brother, Mr. W. Hume 

 McCorquodale. No giraffes had previously been received from 

 this region, and as the skull proved to differ from that of the 

 typical species in its greater size, longer muzzle, and more 

 divergent horns, it was considered to represent a special sub- 

 species, for which the name of Giraffa camelopardalis peralta 

 was suggested. — Mr. Sclater exhibited some photographs of 

 giraffes in order to show the differences in markings between 

 the two forms Giraffa cainelopardalis typica and G. c. capensis. 

 — A letter was read from Mr. J. Graham Kerr, containing notes 

 on the habits of the Paraguayan Lepidosiren, as observed by 

 Mr. R. J. Hunt. It was shown that during the dry .season it 

 retired into burrows like its African relative Protopterus. — Mr. 



G. A. Boulenger, F.R.S., gave an account of the fishes col- 

 lected by Dr. J. Bach in the Rio Jurua, Brazil. Fifty-one 

 species were enumerated, of which nine were described as new. 

 — Mr. F. E. Beddard, F.R.S., read a paper on the anatomy of 



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