334 



NA TURE 



[February 5, 1903 



Perry in which an aluminium ring was supported by a 

 trifilar 1, pen: ion. — A paper entitled " Note on an Elemen- 

 tary Treatment <>f Conducting Networks," by Prof. L. R. 

 Wiiberforce, was read by Sir. Derriman. In this paper 

 the author shows that the well-known reciprocal relations 

 between the parts of a conducting' network can be reaaily 

 established without an appeal to the properties of determin- 

 ants. A paper on the theory of the quadrant electrometer 

 read by Mr. G. W. Walker. For the purpose of some 

 experiments which the author is taking up, he has found 

 ii necessary to examine carefully the theory of a symmetrii al 

 quadrant electrometer, and the results of his investigations 

 are put forward in this paper. The late Dr. John llopkin- 

 son pointed out the imperfection of the usual formula given 

 by Maxwell, and also gave an empirical formula which 

 closely represented his experiments. The general result is 

 well known, namely, that the sensibility of the electrometer 

 rises to a maximum as the potential of the needle is raised, 

 and that any further increase in the potential of the needle 

 reduces the sensibility. The author's experiments have been 

 made with a sensitive electrometer by Bartels, of Gottingen, 

 which shows a maximum sensibility when the potential of 

 the needle is about ioo volts. The sensibility seems to go, 

 on diminishing alter this, at least until very high voltages 

 are used. The formula for a quadrant electrometer is in- 

 vestigated more rigidly than in the text-books, and an equa- 

 tion is arrived ,u which is practically identical with the 

 empirical formula of Hopkinsori, and represents exactly the 

 results obtained by the author from a Bartels' electrometer. 

 fhe equation contains a constant which must be positive to 

 explain the results, and it is shown that this is the case. 

 An investigation is then undertaken to obtain a numerical 

 value lor this constant. 



Zoological Society, January 20. — Prof. G. B. Howes, 

 F.R.S., vice-president, in the chair. — Mr. Budgett read a 

 report on his recent expedition to Uganda. At Butyaba, on 

 the east shore of Lake Albert, Polypterus senegalus and Protop- 

 terns aethiopicus were both abundant, and collections were 

 made of the fishes of the lake and of the higher vertebrates. 

 Mr. Budgett proceeded through the Budonga forest, where very 

 large herds of elephant were frequently seen, to the Victoria 

 Nile below the Murchison Falls. Here ten days were occupied 

 in endeavouring to obtain the early stages of Polypterus, which 

 was fairly abundant and was found to be spawning. '1 he fertilis- 

 ation of more than a hundred ova obtained, however, was not 

 successful, and the most promising attempt yet made to breed 

 Polypterus artificially again failed. Mr. Budgett proceeded to 

 Wadelai overland, staying there a week, but was not very 

 successful here in obtaining material of Polypterus ; but some 

 collections of fishes and birds were made. At Fashoda, several 

 weeks were spent, and a good deal of information concerning 

 Polypterus senegalus, P. bichir and P. endlicheri was obtained. 

 Many anatomical preparations of f^hes were also made here. 

 Throughout the journey, many observations were made upon 

 the birds and mammals, and the striking parallelism of the 

 country of the Nile province of Uganda in its flora and avifauna 

 to that of the Gambia colony on the west coast was especially 

 noticed. Though some new light was shed upon the problem 

 of the life history of Polypterus, earlier stages than those 

 previously observed were not obtained. — Mr. J. S. Budgett 

 also read a paper on the spiracles of Polypterus, in which he 

 stated his opinion that the spiracles of this fish were used to 

 take in and give out air from the swim-bladder. — Mr. F. E. 

 Beddard, F.R.S., read a communication dealing with the 

 surface anatomy of the cerebral convolutions in Nasalis, Colobus 

 and Cynopithecus. The wide differences which the brain of 

 Cynopithecus shows from that of the baboons and its many 

 points of resemblance to the brain of Semnopithecus were 

 pointed out. Colobus was shown to closely resemble Macacus 

 in the structure of its brain. Three brains of Nasalis were 

 reported on, two of which the author owed to the kindness of 

 Dr. Charles Hose, of Borneo. It was stated to be practically 

 impossible to distinguish the brain of this genus from that of 

 Semnopithecus. — Mr. G. A. Boulcnger, F.R.S., read a paper 

 on the fishes collected by Mr. G. L. Bates in Southern 

 Cameroon. Examples of thirty -five species were contained in 

 the collection ; these were enumerated and the new species, 

 nine in number, were described. One of the species was made 

 the type of a new genus — Microsynodontis. — A communication 

 from Mr. W. K. Hutton contained an account of the anatomy 



NO. 1736, VOL. 67] 



o. a gephyrean worm from the Firth of Clyde. As the worm- 

 appeared to be hitherto undescribed, Mr. Hutton proposed to- 

 name it Phaseolosoma teres. — A communication from Dr. J. G. 

 de Man contained the description of a new species of fresh- 

 water crab from Upper Guinea, under the name Potamon (Pota- 

 monautes) latidactyhtm. — Mr. R. I. Pocock read a paper, 

 prepared by the Hon. N. C. Rothschild and himself, 

 containing a description of a new species of spider of the genus 

 I'hrynarachne, discovered by Messrs. Rothschild and E. E. 

 Green in Ceylon. The members of this genus were noteworthy 

 on account of the perfection of their imitation of a patch of 

 bird's dung, which acted as a lure to butterflies. — A communi- 

 cation received from Dr. H. J. Hansen, of Copenhagen, 

 contained a monograph on the crustacean genera Sergestes and 

 Pelalidium, with an excursus on the luminous organs of Ser- 

 gestes challehgeri, n.sp. During a visit to England last 

 summer, Dr. Hansen was empowered by the authorities of 

 the British Museum (Natural History) to examine all the 

 specimens of reputed species of these genera preserved under 

 their care in the extensive " Challenger " Collection. A minute 

 investigation of all the specimens called for some systematic 

 changes, but on the whole confirmed the view which he 

 had expounded in 1896, namely, that many specific names 

 had been needlessly applied to larval forms of species 

 already known in the adult condition. On the other hand, Dr. 

 Hansen found one single specific name covering specimens of 

 four distinct species, two of these being new to science, and one 

 of the new ones being exceptionally remarkable for the posses- 

 sion of luminous organs. These, which were not known to 

 occur in any other species of the genus, were distributed in 

 great numbers over the whole fabric of Sergestes challengeri. 



Edinburgh. 



Royal Society, January 5. — Prof. Flint in the chair. — A 

 paper by Mr. George Romanes was communicated in which 

 the author argued that it was not necessary to suppose that the 

 earth in the course of its evolution had passed through a molten 

 or semi-fluid condition. He showed by definite calculations 

 that the great compression of the interior parts of the earth 

 implied an evolution of heat sufficient for all purposes. The 

 paper gave rise to a lively discussion as to the internal condition 

 of the earth and its probable history, Prof. Knott pointing out 

 that the Helmhohz theory of gravitation, when applied to the 

 earth in its present state, amply sufficed to account for the annual 

 loss of heat. A very slight contraction would prevent the 

 average temperature becoming lowered, although a certain 

 amount of heat was lost every year. — In a paper on the isoclinal 

 lines of a differential equation of the first order, Mr. J. II. 

 Maclagan Weddcrburn. following Lie's idea of a differential 

 equation, namely, that the equation <p (.r, y, p) = o attaches to 

 every point (x,y) a direction/ ( = dyjdx), discussed geometrically 

 the singular loci of the integral curves by means of the singula* 

 hici "I the family of curves obtained by regarding / as an 

 arbitrary constant. This family it is proposed to call the 

 isoclinal family. An isoclinal line has the property that the 

 differential equation attaches the same direction to every point 

 on it. The cases dealt with were where the/ discriminant was 

 (1) an envelope of the isoclinal family, (2) a locus of nodes, (3) 

 a locus of cusps, the corresponding loci on the integral curve 

 being (1) a locus of cusps, (2) a tac locus, (3) a locus of ramphoicl 

 cusps. Tac loci were divided into three classes, according as 

 the curvature was in the same or opposite direction in the two 

 cases, or an inflection on one of the curves. The method was 

 applicable to equations of higher order than the first, and to 

 partial differential equations. 



January 19. — Lord Kelvin, president, in the [chair. — Lord 

 Kelvin read a paper on the reflection and refraction of light, in 

 which further developments were given of two previous papers. 

 In the earlier of these (Phil. Mag., August, 1900), the dynamical 

 dilticulty of conceiving ponderable bodies capable of motion 

 through the highly elastic solid such as ether seems to be was 

 surmounted by supposing that within the sphere of action of an 

 atom of matter the ether varied in density according to definite 

 laws conditioned by assumed attractions and repulsions between 

 the atoms and the elements of ether. As the ether flowed 

 through the space occupied by the matter, or as the atom passed 

 through the ether, the ether was imagined to become condensed 

 towards the centre and rarefied towards the surface of the 

 spherical atom in such a manner that the amount of ether within 

 the spherical boundary was the same as if no atom were present- 



