September 25, 1919] 



NATURE 



87 



thing in tlie dark, and is therefore less tempting to a 

 physicist, until some physical explanation of those 

 fluctuations can be given. At present they seem to 

 be postulated merely in order to secure positions of 

 equilibrium in which an electron can settle down. 

 Orbital revolution achieves the same end, in apparently 

 a more complicated but really a more tractable 

 manner. Moreover, it confers upon an atom ^he 

 sort of energy and structural velocities which are con- 

 spicuous in the various types of radio-activity. True, 

 it is a working hypothesis at present, and nothing 

 more, but it seems likely to be a fruitful one; and 

 that is its present justification. 



The subject is in the nascent or rapidly growing 

 stage; and, provided we refrain from dogmatism, it 

 is legitimate thus tentatively to survey and explore 

 the boundary between knowledge and ignorance, and 

 to speculate as to what may be the next stages in 

 the exhilarating pursuit. 



The apparent resemblance between an atom and 

 the solar system opens up extraordinary vistas for 

 further inquiry. Optics and gravitation still have 

 many secrets. The interactions between aether and 

 matter are as yet barely understood. We know that 

 the energy of an electric current is reallv in the 

 aether, i.e. in the magnetic field surrounding the 

 current; but we must admit that the electromagnetic 

 explanation of inertia is no ultimate explanation ; it 

 is but relegating the property to some fundamental 

 property of_the aether, of which substance presumably 

 matter itself may in seme wav be composed. 



Evidence suggests that the aether is an excessively 

 dense substance, and that it circulates slowlv along 

 lines of magnetic force.' But though so dense we 

 have no means of apprehending it directly. Matter, 

 though so comparatively filmy and fragmentarv, vet 

 looms large in our estimation because of our material 

 sense-organs; its properties force themselves on our 

 attention, because, in fact, our bodies are composed 

 of matter. But underneath and behind all the known 

 properties of matter lie the unknown properties of 

 the aether of space; and if we are to create a true 

 philosophy we must attend continually to aether as 

 well as to matter in the physical universe. The aether 

 makes no appeal to our senses, but it is none the less 

 real for that. Sensation is no test of reality — manv of the 

 most important things are in the insensible universe ; 

 and he is the wisest man who shuts the door on no 

 opportunity for investigation, but keeps his mind 

 open and is readv to explore everv avenue towards 

 truth. 



UNIVERSITY AND EDUCATIONAL 

 INTELLIGENCE. 



Edinburgh. — Considerable developments have re- 

 cently taken place in the departments of pure and 

 applied mathematics of the University. Since 1914, 

 the department of pure mathematics has occupied a 

 separate building, the Mathematical Institute, in 

 ground adjacent to the Arts Quadrangle. This build- 

 ing contains lecture-rooms large and small, mathe- 

 matical laboratory, reading-room with students' 

 librarv, research-room with a library of mathematical 

 periodicals and advanced works, and rooms for the 

 staff. The laboratory course comprises interpolation, 

 construction of mathematical tables, numerical solu- 

 tion of algebraic and transcendental equations, 

 numerical integration, least squares, graduation or 

 adjustment, fitting of normal and skew frequency 



* This view of the cnergv of a mtenetic field, that it is direct kinetic 

 enerey of the aether movitig lonst'ti'dinallv. suuge^ts a noscih'e (or nea^ ly im- 

 possible) experitnrnlal mears of determining the real density of the zther 

 of space — a subject on which I have much more to say. See PAi7. Ma^. for 

 May, 1919. 



curves, correlation, practical Fourier analysis, 

 spherical harmonic analysis, periodogram analvsis, 

 with drawing-board work in nomography, descriptive 

 geometry, and cartography. 



The most recent development is the institution of 

 a diploma in actuarial mathematics. This is intended 

 for students who are employed in the numerous life 

 insurance offices in the city of Edinburgh, and are, 

 therefore, only part-time students of the University, 

 attending, however, day, not night, classes. The 

 course, which covers two years, is conducted on the 

 mathematical side by Prof. E. T. Whittaker, F.R.S., 

 and on the actuarial side by Dr. A. E. Sprague, presi- 

 dent of the faculty of actuaries. Students who obtain 

 the diploma will be exempted from Part I. and 

 Part II. of the faculty's examinations for fellowship. 



The Mathematical Institute is the meeting-place of 

 the Edinburgh Mathematical Society, and houses the 

 library of the society. 



In the department of applied mathematics, which 

 is under the charge of Dr. C. G. Knott, arrange- 

 ments have been made for the inclusion of special 

 honours courses on wave-motion in matter and sether, 

 kinetic theory of gases, and radiation. The former 

 courses on dynamics, hydrodynamics, and elasticity 

 have also been extended, one of the full-year courses 

 being specially adapted to the needs of the student of 

 engineering. There is also a post-graduate course 

 on quaternion vector analysis. 



NO. 2604, VOL. 104] 



Mr. J. S. W. Boyle has been appointed lecturer 

 and assistant in chemistry in University College, 

 Dundee, in succession to Dr. J. K. Wood. 



The Right. Hon. Christopher .Addison, Minister of 

 Health, will deliver the introductory address at the 

 ooening of the winter session of the London (Royal 

 Free Hospital) School of Medicine for Women, Uni- 

 versity of London, on Wednesday, October i, at 

 3 pni. 



The ninety-seventh session at Birkbcck College, 

 Breams Buildings, London, E.G. 4, will commence 

 on Monday next, September 2q. Courses, day and 

 evening, in the faculties of arts, science, laws, and 

 economics for the examinations of the University of 

 London begin on the following Tuesday. Full details 

 of the courses are given in the syllabus of the col- 

 lege, which can be obtained on application to the 

 secretary. 



SOCIETIES AND ACADEMIES. 

 Paris. 

 Academy of Sciences, September 8. — M. Leon 

 Guignard in the chair. — L. Mangin : Notice on the 

 work of the late William Gilson Farlow. — G. 

 Humbert : The measurement of the classes of Her- 

 mite of given discriminant in an imaginary quadratic 

 body, and on certain non-Euclidean volumes. — G. 

 Bigburdan : The work of La Caille (conclusion) and 

 his successors at the Mazarin College. — M. Stuyvaert : 

 The elimination of one unknown between three alge- 

 braic equations. — N. E. Norlund : The principal solu- 

 tion of a certain equation of finite differences. — G. 

 (luillaumin : The transversal effects of contraction in 

 reinforced concrete structures. — P. Chofardet : Ob- 

 servations of Borrelly's comet (igiqc) made with the 

 coudi equatorial at the Observatory of Bosan^on. 

 Observations, with positions of comparison stars, are 

 given for .\ugust 2:;, 27, and 28. The comet is of 

 the loth magnitude, is round, about 2' diameter, 

 with a central condensation. There is no tail. — J. 

 Guillaume : Observations of Borrelly's, Kopff's, and 



