NA TURE 



[May 28, 1896 



the supposition that the traces of bands observed are true carbon 

 Ijands. The author also investigated the spark spectrum of 

 oxygen produced by a dynamo and transformer, and compared 

 the bright lines found with the solar iron lines found in the same 

 positions. The result showed that the oxygen lines, if present 

 in the sun, are not sufticient to cover even the faintest iron 

 absorption lines. Still, the author inclines to the view that the 

 sun's light is due to carbon vapour in an atmosphere of oxygen. 

 — On the determination of the division errors of a straight scale, 

 by H. Jacoby. The author compares every division, and set of 

 divisions, microscopically with every division on a duplicate 

 scale. This is Gill's method. But he improves it by counting 

 the "weight "of each observation according to its true value, 

 instead of assigning the same weight to all readings without dis- 

 tinction. — Rontgen rays not present in sunlight, by M. Carey 

 Lea. The author proved this by trying to obtain radiographs 

 from the sun's light through one hundred leaves of a book, or 

 through aluminium foil. No trace of Rontgen rays was found in 

 sunlight, nor was any found in the light from a Welsbach incan- 

 descent gas burner. — On numerical relations existing between 

 the atomic weights of the elements, by M. Carey Lea. It has 

 already been shown that elements whose ions are always colour- 

 less can be arranged in vertical lines so that the horizontal lines 

 contain each a natural group. Also that the elements whose 

 ions are always coloured, form series with the atomic weights 

 immediately following one another. If the atomic weights in 

 tlie first vertical column are subtracted from those in the second, 

 the second from the third, and so on, certain standard differences 

 are found to recur. One of these is about 16, the other about 46, 

 and the third about SS. The elements with ions always coloured 

 are outside of this rule. Their behaviour is altogether anomalous. 

 The colourless elements, beginning with hydrogen, fall into four 

 series of nine each, interrupted by four coloured groups, and 

 followed by an alternate series, Hg, Tl, Pb, Bi, Th and U. 



Bulletin of the American Mathematical Society, April. — 

 A two-fold generalisation of Fermat's theorem, a paper pre- 

 sented to the Society at its February meeting, is stated by the 

 author, Prof. E. H. Moore, to be one-fold generalisations of 

 two known theorems, of which one may be looked at as a 

 theorem in the ordinary Gauss-congruence theory, while its 

 generalisation is a theorem in the Galois-field theory. It is 

 naturally highly symbolical. Prof. J. Pierpont gives an interest- 

 ing and valuable note on the Ruffini-Abelian theorem. Gauss, 

 in 1799, rigorously established the fundamental theorem that 

 every equation of degree n possesses n roots real or imaginary. 

 When n is less than five, it had been long known that these 

 roots could be expressed as explicit algebraic functions of the 

 coefficients. Between the years 1799 and 1813 an Italian 

 mathematician, Ruffini, made several attempts to establish the 

 justice of the doubts that the roots of equations of degree 

 greater than four possessed this property. His reasoning, how- 

 ever, has not been judged to be conclu.sive, and the question 

 remained open until the putjlication of Abel's argument in 1826. 

 Prof. Pierpont, in addition to the preceding statement, gives 

 several other historical notes, and states that his object is to give 

 a demonstration of the theorem which shall be as direct and 

 self contained ^.% possible. In addition he gives demonstrations, 

 one of which is a modification of Ruffini's form, and the other 

 Kronecker's modification of Abel's form. — On certain subgroups 

 of the general projective group, is a paper, read before the 

 January meeting, by the author. Prof. Henry Taber. It is on 

 the lines of recent previous papers by the author in the Bulletin, 

 the Proceedings of the London Mathematical Society, and the 

 A/athematisc/ie Annalen. The " Notes" give the courses for 

 the summer semester at Berlin and (Jottingen. A synopsis is also 

 published of the first volume of a work of great originality, viz. 

 the Geometric der Beriihrungstransformationen, Dargestellt von 

 Sophus Lie und G. Scheffers. A long list of new publications 

 closes the number. 



SOCIETIES AND ACADEMIES. 

 London. 

 Royal Society, April 30. — "On some Pakeolithic Imple- 

 ments found in Somaliland by Mr. H. W. Seton-Ivarr." By 

 Sir John Evans, K.C.B., F.R.S. 



In the course of more than one visit to Somaliland, Mr. 

 Seton-Karr noticed, and brought home for examination, a number 

 of worked Hints, mostly of no great size, which he laid before 



NO. 1387, VOL. 54J 



the Anthropological Section of the British Association, at the 

 meeting last year at Ipswich.' Although many of these speci- 

 mens were broad flat flakes trimmed along the edges so as to 

 be of the " Ic Moustier type" of M. Gabriel de Mortillet, and 

 although the general fades of the collection was suggestive of 

 the implements being of Pala."olithic age, they did not afford 

 .sufficient evidence to enable a satisfactory judgment to be formed 

 whether they undoubtedly belonged to the Pala-olithic period. 



On returning to Somaliland, during the past winter, Mr. 

 Seton-Karr was fortunate enough to meet with a large number 

 of specimens in form absolutely identical with some from the 

 valley of the Somme and other places. 



Of this identity in form there can be no doubt, and though at 

 present no fossil mammalian or other remains have been found 

 with the implements, there need be no hesitation in claiming 

 them as PaK-olithic. Their great interest consists in the identity 

 of their forms with those of the implements found in the 

 Pleistocene deposits of North Western Europe and elsewhere. 



The discovery aids in bridging over the interval between 

 Palaeolithic man in Britain and in India, and adds another 

 link to the chain of evidence by which the original cradle of the 

 human family may eventually be identified, and tends to prove 

 the unity of race between the inhabitants of Asia, Africa, and 

 Europe, in Palaolilhic times. 



May 7. — "The Electromotive Properties of the Electrical 

 OxffiXi o{ Malapterurusetectricns.^'' By Francis Gotch, F.R.S. , 

 and G. J. Burch. 



The conclusions drawn by the authors from the experiments 

 on the isolated organ and on the entire uninjured fish may be 

 summarised as follows : — 



(1) The isolated organ responds to electrical excitation of its 

 nerves by monophasic electromotive changes, indicated by 

 electrical currents which traverse the tissue from the head to the 

 tail end ; this response commences from 0"oo35" at 30" C. to 

 O'oog" at 5° C. after excitation, the period of delay for any 

 given temperature being tolerably constant. 



(2) The response occasionally consists of a single such mono- 

 phasic electromotive change (shock) developed with great 

 suddenness, and subsiding completely in from 0'0O2" to 0'005", 

 according to the temperature ; in the vast majority of cases the 

 response is multiple, and consists of a series of such changes 

 (shocks) recurring at perfectly regular intervals, from two to 

 thirty times (peripheral organ rhythm) ; the interval between 

 the successive changes varies from 0*004 '' ^'^ 3°" C. to 0"0I at 

 5° C. , but is perfectly uniform at any given temperature through- 

 out the series. 



(3) Such a single or multiple response (in the great majority 

 of cases the latter) can also be evoked by the direct passage of 

 an induced current through the organ and its contained nerves, 

 in either direction heterodromous (/.f., opposite in direction to 

 the current of the response) or homodromous. 



(4) The time relations of the response are almost identical 

 whether this is evoked by nerve-trunk (indirect stimulation), or 

 by the passage of the heterodromous induced current. 



(5) There is no evidence that the electrical plate substance 

 can be excited by the induced current apart from its nerves, 

 i.e. it does not possess independent e.vcitability. 



(6) The organ and its contained nerves respond far more 

 easily to the heterodromous than to the homodromous induced 

 current, and the period of delay in the case of the latter response 

 is appreciably lengthened. 



(7) The peripheral organ rhythm (multiple response) varies 

 from about 100 per second at 5° C. to about 280 per second at 

 35° C. 



(8) One causative factor in the production of the peripheral 

 rhythm is the susceptibility of the excitable tissue to respond to 

 the current set up by its own activity (self-excitation). 



The authors further conclude that, since each lateral half of 

 the organ is innervated by the axis cylinder branches of one 

 efferent nerve cell, and has no independent excitability, the 

 specific characters of the reflex response of the organ express far 

 more closely than those of muscle the changes in central nerve 

 activity, and are presumably those of the activity of a single 

 efferent nerve cell. 



The single efferent nerve cell, the activity of which is thus for 

 the first time ascertained, shows — 



(a) A minimum period of delay of O'OoS" to 0"0l". 



{It) \ maximum rate of discharge of 12 per second. 



1 Report iS95 p. 824 



