April 13, 1899] 



NA TURE 



575 



September 30, 1S98, was 8277, as compared with the 91 16 

 students of the previous year — a decline of 839. A further 

 decline appears probable for the current year. This reduction 

 of numbers is attributed to the extension of the Evening Con- 

 tinuation Schools of the London School Board, in Which all 

 fees have now been abolished, and to the establishment by the 

 Board, close to the Institute, of certain special centres, at which 

 many of the subjects already provided for by the Institute are 

 taught gratis. The Governors point out that action of this 

 kind on the part of a body having the control of public funds is 

 open to much question, and, if persisted in, may render volun- 

 tary effort, by means of private resources useless, if not impos- 

 sible. It is to be hoped that the appointment of a single 

 authority to be responsible for technical and secondary education 

 in London will be the means of preventing the unfortvmate 

 overlapping and undesirable competition referred to by the 

 GoverningBody in their report. The Institute should be given a 

 definite place in the scheme of education in London and nothing 

 should be permitted to interfere with its progress. 



SCIENTIFIC SERIALS. 



Bulletin of the American Mathematical Society, March. — 

 On singular points of linear differential equations with real co- 

 efficients, by Prof. M. Bticher (read before the Society, October 

 29, 1898). Take the equation 



dx" ax" ' 



■+p,'y-- 



where the coefficients (/,, &c.) are throughout a certain interval 

 a-^x-^b, continuous real (but not necessarily analytic) functions 

 of the real variable .v. By a solution the author understands 

 any function of .v which together with its first « - I derivatives 

 is single valued and continuous throughout the interval a <a'<c(^, 

 and at every point of this interval satisfies the above equation. 

 It is well known that there is one, and only one solution which 

 at an arbitrarily chosen point of the interval in question has 

 together with its n - 1 derivatives arbitrarily chosen values. 

 The object of the paper is to consider the behaviour of these 

 solutions as we approach one end of the interval. Prof. Bocher 

 confines his attention to the point a. Reference is made to two 

 papers by Kneser ("Crelle," vols. 116,117). The paper is an ex- 

 tension and generalisation of some of the author's results obtained 

 in a previous paper of this current volume, entitled "The 

 theorems of oscillation of .Sturm and Klein." — Some interesting 

 results are given in the Hessian of the cubic surface, by Dr. J. 

 I. Hutchinson (read at the Boston, Mass., meeting, August 

 1898). — On the simple isomorphisms of a Hamiltonian group to 

 itself, is a notelet read, at the same Boston meeting, by Dr. G. 

 A. Miller. In the paper each system of conjugate operators is 

 supposed to contain more than one operator unless the contrary 

 is stated. The results are expressed in three theorems with 

 attendant corollaries. Useful reviews follow : — QLuvres mathc- 

 niatiquesd't-variste Galois (published by the Paris Mathematical 

 Society). — These sur la geometric non-euclidienne, by M. L. 

 Gerard ; Lezioni di geometria intrinseca, by E. Cesaro ; L'hyper- 

 spacea(«-i) dimensions; Proprietes metriques de la corre- 

 lation generale, by G. Fontene : Theorie der Abel'schen 

 functionen, by Dr. H. Stahl ; Differenzrechnung, by A. A. 

 Markoff. All these notices are carefully drawn up, and are 

 replete with bibliographical references. The last work, in its 

 German form, is highly praised, and "no one interested in the 

 calculus of finite differences can afford to be without this valuable 

 treatise " is the reviewer's verdict. Information follows on the 

 usual lines. 



The new number of the Archives of the Roentgen Ray con- 

 tains Major Battersby's paper, read before the Rdntgen Society, 

 on the present position of Rtintgen rays in military surgery on 

 January 10, illustrated by several fine plates reproduced from 

 photographs and radiographs taken in Egypt during the recent 

 war in the Sudan. There is also a translation of Prof. 

 Riintgen's further observations on the properties of X-rays, 

 being the third communication to the Royal Prussian Academy 

 of Sciences, Berlin, and dated March 10, 1897. 



Among the articles in the April number of Nattiral Science 

 is one on the development of rivers, and particularly the genesis 

 of the Severn, a translation of Prof. A. Weismann's essay on 

 " Regeneration : Facts and Interpretations." 



NO. 1537, VOL. 59] 



SOCIETIES AND ACADEMIES. 

 • , Edinburgh, 

 Royal Society, March 20. — Prof. G'opeland in the chair. — 

 Sir John Murray read a paper on the teniperature over the floor 

 of the ocean, and the maximum and mihiminn temjierature of 

 the surface of the ocean. The re.snlts wete' lexhibited in charts, 

 and showed that 92 per cent, of the bottom iwater of the ocean 

 had a temperature under 40° F. Highir.vttmperatures were 

 met with in areas between the shore and tibe hundred-fathoiri 

 line. As regards the surface waters, S/^er'/cent. of the maxi- 

 mum temperatures, and 75 per cent, of iftei'minimum tempera- 

 tures, were above 40° F. Sir John Murray pointed out the 

 important bearing the distribution of the temperature had upon 

 nature and amount of the calcareous deposits. — Prof. Cossar 

 Ewart, in a paper on contributions to the theory of heredity 

 (Part ii.), took up the question of intercrossing and variation. 

 The paper might be described as a critical examination of the 

 favourite dictum that intercrossing had a swamping effect, and 

 curbed variation ; and, at the same time, an argument in favour 

 of the view that intercrossing had, like cross-fertilisation, a 

 power of inducing variation. No concrete examples could be 

 adduced of intercrossing leading to uniformity. On the other 

 hand, notwithstanding free intercrossing, a new variety of the 

 peppered moth, which recently appeared in England, had 

 gradually displaced over a considerable area the parent form. 

 Prof. Ewart's own experiments on intercrossing among half-wild 

 rabbits favoured the view that intercrossing induced rather than 

 arrested variation. The paper ended with a discussion of the 

 relative value of intercrossing and change of environment as 

 rejuvenators, one conclusion being that, while the constitution 

 might be bettered by a change in the environment, active 

 variation seemed to result from the disturbance that accompanies 

 or flows from intercrossing.— A paper by Dr. T. Muir, on a 

 development of a determinant of the m «th order was also com- 

 municated. 



P.ARIS. 



Academy of Sciences, April 4. — M. van Tieghem in 

 the chair. — Observation of the planet EL (Coggia, March 31) 

 made at the Observatory of Paris with the 38 cm. equatorial, by 

 M. O. Callandreau.— Observations of the planet EL 1899, dis- 

 covered by M. Coggia at JIarseilles, March 31, by M. Stephan. 

 On the deformation of surfaces of the second degree, by M. G. 

 Darboux.— The calculation by a simple hypothesis of the 

 lateral displacement which should be given to a rider on a 

 bicycle in motion, to carry the centre of gravity of the system to 

 any given small horizontal distance from the base of the 

 machine, by M. J. Boussinesq. — On the synthesis of alcohol, by 

 M. Berthelot. The author shows that although Hennell 

 I probably prepared potassium ethyl sulphate from ethylene, he 

 does not appear to have attempted to have prepared alcohol 

 from this, as is usually stated in the text-books. — On anthero- 

 zoids and double sexual copulation in the angiosperms, by M. L. 

 Guignard. The observations made by the author upon the 

 fertilisation of Lilium Martagnon confirm generally the results 

 of M. Nawaschin, the essential phenomenon consisting of a 

 double sexual copulation in the embryonic sac, one giving rise 

 to the embryo, the other furnishing the albumen necessary to 

 the nutrition of the embryo. The paper is illustrated by nine- 

 teen diagrams. — Observation of the Swift comet (1S99 a) made 

 at the Observatory of Algiers, by MM. Trepied, Rambaud, and 

 F. Sy.— Observations of the Swift comet (1899 a) made at the 

 Toulouse Observatory with the 23 cm. equatorial, by M. F. 

 Rossard. — On several linear groups isomorphous with the simple 

 group of order 25920, by M'. L. E. Dickson. — .4 rapid method 

 for the determination of the specific heat of liquids, by M. D. 

 Negreano. The method is based upon the comparison of the times 

 required to raise the same volumes of the liquid and of water i ' 

 by means of a wire spiral carrying the same current. — On the use 

 of diffraction fringes in increasing the delicacy of galvanometer 

 readings, by M. Pierre Weiss. The method suggested increases 

 the delicacy of reading a given galvanometer four times.— On 

 the Wehnelt electrolytic contact-breaker, by M. A. Blondel. — 

 On the ab-sorption of the Hertzian waves by non-metallic bodies, 

 by MM. l<;douard Branly and Gustave Le Bon. The opacity 

 of non-metallic substances to the Hertzian waves depends upon 

 the thickness and nature of the substance, sand and stone being 

 very transparent, Portland cement much more opaque. Moisture 

 increases the opacity.— On a mode of obtaining electric figures 



