56S 



NA 7 URE 



April lo, I S3 I 



certain iion ores hclonging to the class of globular ores, by M. 

 Diculafait. — On the solar halos observed at Saint Maiir on the 

 morning of March 29, by M. E. Renou. — Note on the presence 

 of manganese in the wines of Grave, by M. E.iJ. Maumene. 



Berlin 

 Physical Society, March 7. — Prof. Neesen, by means of 

 different glass tubes, demonstrated certain ]>henomena of Kundt's 

 dust figuies produced by experimenling with deep tones. Busied 

 \^■ith an examination into the cause, not yet explained, of the trans- 

 verse ridgings in sounding-tubes, Prof. Neesen ha<, instead of the 

 hi^h tones of longitudinally-vibrating tubes, tested deeper tones, 

 which are kept up in the column of air of the glass tubes by an 

 electric tuning-fork. In the course of this investigation he 

 made very beautiful observations in many tulles of dust-whirls 

 roaming hither and thither, now to one tide, now to the other. 

 In other tubes, again, the?e whirls cnme to light either with 

 great difficulty or but imperfectly. It would therefore appe.ir 

 that the material of the tubular wall exercised some influence 

 on the production of those whirls. The speaker had yet, how- 

 ever, come to no definite result respecting the cause of the 

 transverse ridges. — Dr. Krenig supplemented the experiments 

 he communicated at the last sitting of the Society, on the sensi- 

 tiveness of normal eyes for variations of colour between the 

 wave-lengths of 640 and 430. This he had so far done, 

 inasmuch as he bad tested the influence of light-intensity on the 

 sensibility in que-tion. Seeing, as was well known, that light- 

 intensity, in this part of the spectrum especially, mounted very 

 rapidly from the line C to the line D, and again sank from 

 the maximum beyond D down to F, it would be pos-ible that 

 the differenliating sensibility arrived at in the former experi- 

 ment-; was in large part conditioned by the differences of 

 intensity. The cooperation of intensity was now in the new 

 experiments partly excluded as a factor in this way, that 

 the spectrum was observed through an absorbing medium 

 whose maximum of absorption stood at D, S5 that the curve 

 of light-intensity between C and D rose with much less 

 rapidity, ran horizontally for some distance, and then sank to 

 1). The measurements, being carried out as in the former ex- 

 periments, yielded the result that the differentiative sensibility 

 under the conditions mentioned had undergone very little alter- 

 ation, and that, consequently, light-intensity had no influence on 

 the range that had been arrived at. — Prof, von Helmholtz re- 

 ported on a theoretic treatise he had laid before the Berlin 

 Royal Academy, in which he had taken in hand the task of ex- 

 phiining, in accordance with mechanical principles, thermal 

 movements, and more particularly Carnot's law. He attained 

 his object by means of the rules bearing on stationary move- 

 ments, as they were calculated for a vortex revolving withinit 

 fj'iction and with great velocity, or for a fluid moving without 

 fricti- n in a closed circular canal. The equations for these 

 stationary movements derived from mechanics corresponded with 

 those derived from Lagrange's law for thermal movements. 



Physiological Society, March 14. — Prof. Lucae gave an 

 address on tire subject of subjective auricular sensations and their 

 treatment. He showed by examples that the idea that subjective 

 auricular sensations, and in particular the generally known one of 

 singing in the ears, had a somatic cause, such as stoppage of the 

 external acoustic duct or of the Eustachian tube, was not in 

 accordance with experience. Both on himself and on persons of 

 musical culture he had determined the pitch of the singing or 

 whistling sound, and had found it equal to the proper tone of the 

 external acoustic duct. This circumstance, together with several 

 other facts, led him to the conjecture that the singing in the ears 

 was caused by a tetanus of the tensor tympani, which set the air 

 over the membrane of the tympanum in continuous oscillation. 

 In cases of suffering from this distemper, of which the speaker 

 cited a number of examples, the subjective auricular sensations 

 v/ere lo be divided into such as were intensified and such as were 

 abated by external sounds. Both kinds were to be regarded as 

 phenomena of abnormal resonance, and were accompanied by 

 different degrees of hardness of hearing down to deafness. Tlie 

 treatment of these subjective sensations, so far as they were 

 simple tones and noises, and not the subjective hearing of words 

 or of anything outside the hearer (disturbances psychological 

 and beyond the scope of his address) consisted, in the opinion of 

 the speaker, an opinion based on manifold personal experience, 

 in subjecting the sufferers, for progressively longer periods of 

 time, and for as many as two to three minutes at once, to a certain 

 cinstant tone of the tunin<;-fork. In such a case Prof. Luca • 



used deep tuning-forks with such as heard subjective high tones, 

 and vice rasa. With the cessation of the subjective noises the 

 deafness also usually disappeared, and the suflferei'S recovered a 

 permanently normal slate in this respect. An explanation of 

 this phenomenon the speaker thought might be found in the 

 analogy of other sensations in which abnormal excitement in one 

 part of the sensory nerves was relieved by the excitement of 

 neighbouring nervous parts. — Prof. Munk reported on a treatise 

 sent for insertion in the Vciimndlungen by Dr. Gad, a foreign 

 member. Contraiy to the opinion on the subject hitherto enter- 

 tained. Dr. Gad in this treatise proved that in the spinal marrow 

 of frogs, even under the seventh nerve-root, there were reflex 

 centres in operation. By cutting through the spinal marrow, 

 below this spot, reflex convulsions from the toes upwards are 

 produced, not only on the same but also on the opposite side. 

 In other experiments on frogs the spinal marrow was cut through 

 beneath the medulla oblongata, and the upper part of the spinal 

 marrow as far as the second vertebra carefully prepared and laid 

 on filtering paper saturated with strychnine. On stimulating 

 the frog at the lower extremities reflex movements were seen to 

 pervade the whole body, but in the region of those sections of 

 the spinal marrow treated willi strychnine, flexor spasms were 

 observed, though it is well known to be a special characteristic 

 of the strychnine spasm that it exclusively attacks the extensor 

 muscles. In this way was demonstrated the existence of con- 

 ducting tracks rising from the reflex centres situated in the lower- 

 most part of the spinal marrow up to its topmost parts. If these 

 latter, again, were electrically stimulated, no flexor movement 

 could be started from the spot which before, under the opera- 

 tion of strychnine, had generated exterior reflections. Between 

 this part of the spinal marrow and the motory nerves there must 

 therefore lie ganglia. — Following up his communication at the 

 last sitting, on the presence of nitric acid in urine. Dr. Weyl 

 brought before the Society a series of chemical reactions tending 

 to demonstrate that nitric acid could exist and be substantiated 

 in an oxidised solution along with urea. 



CONTENTS Page 



Stokes on Light. By Prof. P. G. Tait 545 



Our Book Shelf :— 



Gray's "Absolute Measurements in Electricity and 



Magnetism " 546 



Duthie and Fuller's "Field and Garden Crops of the 



North-Western Provinces and Oudh " 547 



Lock's "Treatise on Higher Trigonometry " . . . 547 

 Letters to the Editor : — 



Teaching .\nimals to Converse. — Sir John Lubbock, 



Bart., M.P., F.R.S 547 



"The Unity of Nature." — George J. Romanes, 



F.R.S 548 



The Remarkable Sunsets. — Robt. J. Ellery : S. E. 



Bishop ; Prof. J. P. O'Reilly 54S 



Meteorological Bibliography. — G, J. Symons, 



F-R-s : 550 



Ice \olcanoes — Mountain Rainbow. — A. P. Colman 5:;o 

 Thread-twisting.— Dr. J. Rae, F.R.S. ; Henry 



Faulds 550 



Colony of Cats. — George Ray leigh Vicars . . 551 



Earthworms. — J. Lovell 551 



"The .Vxiomsof Geometry." — Edward Geoghegan ^\\ 

 Geology of Central Africa. By Henry Drum- 



mond 5^1 



Chinese Palaeontology. By Prof. Robert K. Douglas 551 

 On the Formation of Staich in Leaves. By Prof. H. 



Marshall Ward ^i;^ 



Telephony and Telegraphy on the same Wires 



Simultaneously {With Diagrams) 554 



Notes ^^(1 



Our Astronomical Column : — 



Comet 18841! 55S 



Variable .'^lar^ 55,8 



The Observatory, Cincinnati 55S 



The " .■Vstronomische Gescllschaft " 5^8 



Physical Notes 558 



Bacteria 550 



The Stability of Ships. V.yProt E,\s.a.x(ll'ith Diagiams) 559 



The Institution of Naval Architects 563 



Scientific Serials 56s 



Societies ard Academies q6; 



