70 



NATURE 



[May 1 6, 1895 



nectecl with the positive or «nth the negative terminal of a little 

 Voss electric machine, its fumes (prmUicts of combustion mixed 

 with air) sent through a block-tin pipe, four metres long, ami 

 one centimetre Ixire, ending with a short insulating tunnel of 

 paraHin and the electric filter, gives strong positive or strong 

 negative electricity to the filter. 



§ iS. Using the little biscuit -canister and electrified needle, 

 as described in "our communication" * to the Royal Society " On 

 the Diselectrificaiion of .-Vir," but altered to have two insulated 

 needles with varieil <listances of from half a centimetre to two or 

 three centimetres l>etween them, we find that when the two 

 needles are kept at equal ditTerences of potential positive and 

 negative, from the enclosing metal canister, little or no electrifi- 

 cation is shown by the electric filter : and when the differences of 

 potential from the surrounding metal are unequal, electrification, 

 of the same sign as that of the needle whose difference of 

 potential is the greater, is found on the filter. 



When a ball and needle-point are used, the effect found depends 

 chiefly on the difl'erence of potentials between the needle-point 

 and the surrounding canister, and is comparatively little afl'ected 

 by opposite electrification of the Ijall. When two balls arc used, 

 and .sparks in abundance jKiss between them, but little electricity 

 is depfisited by the sparks in the air, even when one of the balls 

 is kept at the same jiotential .is the surrounding metal. [The 

 communication was illustrated by a re|>etilion of some of the 

 experiments shown on the ix:casion of a Friday evening lecture t 

 on Atmospheric Electricity at the Royal Institution on .May l8, 

 i860, in which one half of the air of the lecture-room was 

 electrified positively, and the other half negatively, by two 

 insulated spirit lamps mounted on the positive and negative 

 conductors of an electric machine.] 



<2) "OX TIIK THER.MAL CONDL'CTIVITV OK ROCK 

 AT niKKr.RKN'r TKMl'KR.VTURKS." 



Experiments by Lord Kelvin and Mr. Erskine Murray 

 were descrilxfd, and the apparatus used in them was shown, by 

 which it was found that the thermal conductivity of specimens of 

 slate, sand.stone, and granite is less at higher temperatures than 

 at lower for each of these rocks. The last tested was .Vberdeen 

 granite, for which experiments of fairly satisfactory accuracy 

 showed the mean conductivity for the range from I46°C. to2i5"C. 

 to be 86 per cent, of the mean conductivity in the range from 

 81° C. to 146° C. They hope to send a cimimunication to 

 the Royal Society describing their work before the end of the 

 present session. Kf.ivi.n. 



UNIVERSITY AND EDUCA TIDNAL 

 INTELLIGENCE. 



O.XFORI.. — Mr. I). R. I'ike, of the Charlerhouse. h.is been 

 elected to an open Exhibition in Natural Science .at lesus College, 

 and Mr. L. C. W. IJrigstocke, of Haverfordwest Clrammar 

 -School, has lieen elected to a Welsh Foundation Scholarship in 

 Natural .Science at the same College. 



Open .Scholarships and Exhibitions in Xalural Science have 

 been announced forcom|)etitional Merlon College, New College, 

 Magdalen College, and Corpus Christi College. Particulars 

 may lie obtained on application lo the Dean in any of these 

 Colleges. 



Cambridof..— The Walsingham Medal for an original mono- 

 graph on a botanical, geological, zoological, or physiological 

 subject will l)c awarded in the .Michaelmas Term. Ess.ays are to 

 be sent to I'rof. Newton by Octoljcr lo, 1895. Candidates must 

 Vx- B.A.'s not of st.anding lo take the M..\. degree. 



The subicct for the .Adams Prize of 1897 is connected with 

 Bcssel's Functions. It is set forth in the Uiiivenity Keporler 

 for .May 14. The prize is t)f the value of alMiul ^^197. It is o|)en 

 to all graduates of the University. Es.s.iys are to be sent to the 

 Vice-Chancellor by December 16, 1896. 



The Associalir.n of Technical Institutions has endeavoured to 

 induce the Science and Art Dejnrtment lo discontinue the exam- 

 inations now held in pracilral morganic and organic chemistry, 

 and lo award allendiim r grants for instruction in those subjects, 

 the amount of such grants lo \k de|x.-ndent ujKin the report of 

 Ihe Deijortmenl's ins|)iriors on the efficiency of the c(|Uipment 

 and leaching. TTie ,\sMK-i.iiion has recei%'cd a reply lo Ihe eflTccl 



• PnHttitingi of Ihe Koyjil Socirly, March 14, 1895. 

 I " EicclrMlalicj and M.ii;nciiitni, xvi, tl J85, jM. 



that it is not possible for the Department to comply with their 

 request. .V new syllabus for jiractical inorganic chemistry 

 will appear, however, in the forthconiini; edition of the Science 

 and .\rt Director}-, and there seems little doubt that the instruc- 

 tion will be .so arranged in it as to make it po,ssible to coordinate 

 more closely the laboratory and lecture work in that subject, and 

 afford the same latitude to teachers as is given by the new 

 Regulations for Organised Science Schools. 



SCIENTIFIC SERIALS. 



American lounial of Mathematics, vol. xvii. No. 2 (Haltimore, 

 April 1895). — \ method for calculating simultaneously all the 

 roots of an equation, is a paper by Dr. K. McClintock, which 

 was re.-id before the American .M.athematical Society on August 14 

 and October 27, 1S94. It opens with the application to an 

 example employed by Spitzerand by Jelinek. The calculations 

 of these mathematicians can only be ilone for a pair of roots at 

 a time, and that with considerable difficulty. The method em- 

 ployed by our author is fairly facile. \ery little has hitherto 

 been done in the direction of this memoir, which is one of great 

 value in the subject of algebraic equations. The writer discusses 

 eleven examples at length, the highest degreed equation being 

 one of the sixth degree in .r. — Sur le logarithme de la fonciion 

 gamma, by Ilermite, is a note upon Raabe's integral, in con- 

 tinuation of an article in the Math. Annalcn (41, p. 5S1). — 

 Sur la pres.sion d.ans les milieux dielectricjues ou m;ignetiques, 

 by Prof. P. Duheni, corrects an error in his " Le<;i)ns sur TElec- 

 tricile el le magnetisme," and is a valuable working out of the 

 theory of the pressures, initiated by Clerk .Maxwell, and further 

 improved by von llelmholtz, Kirchhoff, and other writers. Tlie 

 number closes with an article on ternary substitution-groups ot 

 finite order which leave a triangle unchanged, liy II. Maschke. 

 This paper is complementary to C. Jord,in"s " Sur les equations, 

 differcntielles linc.aires a integrale algcbrique," iind " .Sur la 

 determination des groupcs d'ordre fini contenues dans le grou]>e 

 lineaire." 



Zeitschrift fur wissenschaftliche Zoologie, Hd. lix. I left l.^ 

 Prof. A. R. von Ileider gives a detailed description of a new 

 Actinian (Zoanthiis chicrchice) obtained during the cruise of the 

 Vcttor Pisani. Prof. A. Korotneff describes the embry<inic 

 (levelopnieiu of Salpa democratica. According to hint the 

 follicle-cells do not play the inqxirtant part in the development 

 of Salpa which Salensky attributed to them, nor do they form a 

 temporary scaffolding for the blastomeres, .as stated by lirooks. 



I The embryo is built up of blastomeres in the normal manner, and 



I embryonic layers are present with the same significance as in 

 other groups. The cloaca is fcirmed by the union of entlodernial 

 diverticula, and the )iericardium develops as an outgrowth of the 

 pharynx. -I'rof. W. Schimkewitsch writes upon the slruoUire 



I and development of a species of Dinophilus living in the White 

 Sea, ne.ar the Solovetzki laboratory. The twofold affinities of 



I this interesting type, on the one hand with the .\nnelids, and on 

 the other with the Rotifers, are .succinctly stated. — Prof. 

 V'ejdov.sky writes upon the sexual apparatus of Lttmhrictttu< 

 •,'ariei;atiis. — Dr. .Montgomery deals fully with the anatomy of a 

 new type of Nemertine {.Stic/iostcmma Eilhardi) discoverecl in 

 fresh - water a(|uaria in thePerlin Zoological Institute. — Dr. McKini 

 describes the nephridial funnel apixiratus of Hiriido. 



NO- 1333. VOL. 52] 



SOCIETIES AND ACADEMIES. 



I'.lUNIltlRC.M. 



Royal Society, .Match 18.— The Rev. Prof. Flint, Vice- 

 President, in the chair. Prof Crutn-Hrown communicated a 

 paper, by .Mr. R. Fairbairn and himself, on the .action of so'liuin 

 mercaptide oti dibromomalonic ether. — Prof. J. C. Ewarl com- 

 municated a paper, by Mr. F. J. Cole and himself <m the dorsal 

 branches of the cranial and spinal nerves in elasmobratichs. — 

 Dr. Traquair read a |>aper on phosphorescenl .sandstones. — 

 Prof Tail read a note on ihe electromagnetic wave-surface. 



April I. — Sir Douglas Maclagan, President in the chair. — A 

 liaper, by the Duke of .\rgyll, on Ihe gl.iciation of two glens, 

 was read. The glens are (ilenaray and Cilenshira. The usual 

 explanation of Ihe phenomena of gl.acialion as observed in 

 the West Highlands is that Ihe glacialion was caused by an 

 enormr)Us icecap covering Ihe whole country. His Grace does 

 not consider that the phenomena can t>e so explained. Rocks 

 are found which are si riated and smoothed <m one side, while Ihe 

 other side remains rough. Isolated blocks, wilhotit striation, 



I 



