496 



NA TURE 



[Seiteml'ER 12, 1901 



an introductory lecture by Dr. F. W. Andrews. The winter 

 session at Charing Cross Hospital will open on Wednesday, 

 October 2, when an introductory address will be delivered by 

 Prof. J. W. Taylor. At the inauguration of the sixtieth session 

 of the School cf Pharmacy, the Hanbury gold medal will be 

 presented, and the inaugural address will be delivered by Dr. 

 Arthur P. Lufif. At the Royal Veterinary College the sessional 

 course of instruction will be opened with an introductory address 

 delivered by Dr. E. M. Crookshank. The winter session at 

 ^'orkshire College, Leeds, will open on October i, when an 

 introductory address will be delivered by Sir W. S. Church. At 

 University College, Sheffield, the session will be opened with 

 an introductory address by Sir Thomas Barlow. 



Several prospectuses and calendars of technical institutions, 

 showing the courses of work for the session just commencing, 

 have been received. The London Polytechnics give prominence 

 to the announcement that are recognised as qualified institutions 

 from which students who have matriculated in the University of 

 London may be presented for the new engineering degrees of the 

 I'niversity. Courses of work suitable for such students have 

 been arranged, and they should be the means of extending the 

 knowledge of the science of engineering. In the prospectus of 

 the Battersea Polytechnic, trade students are rightly warned 

 against only attending classes connected with their occupations. 

 It is pointed out that the principles of science must be studied, 

 as well as technical subjects, if a thoroughly sound knowledge is 

 desired. Without a working acquaintance with mathematics, 

 mensuration and geometry it is almost impossible to make any 

 real and useful advance in science and technology. This ought 

 to be clearly understood, and it is worth while to consider 

 whether students should not be compelled to give evidence of 

 such knowledge before being permitted to join technological 

 classes, where their presence is often a hindrance to progress. 

 The calendar of the Northampton Institute, Clerkenwell, also 

 contains much good advice as to the choice of studies, and the 

 objects to be borne in mind. Among the noteworthy character- 

 istics of the work of this Institute are the electrochemical 

 laboratory, which has been equipped in a very complete manner, 

 the attention given to horological engineering, and the depart- 

 ment of optical and scientific instruments. But while there is 

 evidence of progress in the work of our polytechnics and tech- 

 nical schools, there is still much to be done before they reach 

 the standard of similar institutes in Germany and the United 

 States, such, for instance, as the Rose Polytechnic Institute, 

 Terre Haute, Indiana, the new calendar of which is before us. 

 Each of the courses in this Institute occupies four years of three 

 terms each, and no undergraduate student is permitted to elect 

 any special or partial course. All students must take full work 

 in one of the courses, and each member of the senior class must 

 present a thesis recording an independent investigation at the 

 close of the year. The value of this educational policy is indi- 

 cated by the high positions which the alumni of the Institute 

 occupy as professional engineers. 



SOCIETIES AND ACADEMIES. 



London. 



Royal Society, June 20. — "On the Resistance and Electro- 

 motive P'orces of the Electric Arc." By W. Duddell, Whitworth 

 Scholar. Communicated by Prof. W. E. Ayrton, F. R.S. 



The author considers that the new facts given in the paper 

 assist in formulating a consistent explanation of the resistance 

 and back E. M.F. of the arc. The values found for the resistance 

 of the vapour column and for the contacts between it and the 

 electrodes offer no serious difficulties. The greater part of the 

 two E. M.F. 's are considered as being most probably due to 

 thermo-electric forces, and experiments in support of this view 

 are described, in which it was found possible to obtain a P. D. 

 of 06 volt by unequally heating two solid carbon electrodes 

 with a blow-pipe flame, the voltmeter indicating that the hotter 

 carbon was positive to the cooler. By using lored carbons and 

 adding potassium salts, this P.D. was increased to f5 volls. 

 It is pointed out that the differences of temperature existing in 

 the arc must be many times as great as those which it is possible 

 to produce with the blow-pipe, as the cooler electrode must be 

 red-hot, or else it does not seem to make contact with the 

 surrounding flame. 



On the Resistance of an Electrolyte. — In measuring the resist- 

 ance of an electrolyte by the Kohlrausch method, it is often 

 assumed that the errors due to polarisation are avoided if the 

 frequency of the alternating or interrupted current used is as high 

 as a few hundred periods per second. Experiments made to test 

 this point lead to the conclusion that unless other methods are 

 adopted to eliminate the effects of polarisation, it must not be 

 assumed that the use of alternating currents of ordinary frequencies 

 of afe-w hundred periods per second eliminates the possibility oj 

 errors due to polarisation. 



Paris. 

 Academy of Sciences, September 2. — M. Bouquet de laGrye 

 in the chair. — On the application of the equations of Lagrange 

 to electrodynamic and electromagnetic phenomena, by M. E. 

 Sarrau. The application of the method of Lagrange to elec- 

 trical phenomena leads to results which are naturally in accord 

 with the principle of energy, since this principle is only one form 

 of the theorem of kinetic energy, and this is a consequence of 

 the general equations. But for this agreement to e.xist it appears 

 to be neces.sary to admit that the internal energy of a system of 

 currents and magnets is purely kinetic, no part of it being po- 

 tential. — On the quadratic transformation of Abelian functions, 

 by M. Georges Humbert. — Observations of the Encke comet 

 made at the Observatory of Algiers, by MM. Rambaud and Sy. 

 Observations of the magnitude, apparent positions of comparison 

 stars, and apparent positions of the comet taken between the 

 9th and 1 8th of August. — On the continuous deformation of 

 surfaces, by M. G. Tzitzeica. — Outline of a general theory of 

 mechanisms, by M. G. Koenics. — On the equilibrium of elastic 

 bodies, by M. R. Liouville. — Evaluation of the resistance of steel 

 to traction deduced from the resistance to shearing, by M. Ch. 

 Fremont. The curve for resistance to shearing per square milli- 

 metre plotted as ordinates against the resistance to extension as 

 abscissae is a straight line. — On the first stages of development 

 of some Polycystidea, by MM. L. Leger and O. Duboscq. Ob- 

 servations on three groups of Polycystidea, Actinocephalides, 

 Dactylophorides, and Clepsidrinides, show that the typical evo- 

 lution allows no intracellular stage. They dift'er in this respect 

 from the intestinal Monocystidia, as has been shown by 

 Caullery and Mesnil. — On scissiparity in the Hydroides, by M. 

 Armand Billard. — On the appearance of the white rot [Charrinia 

 Diplodiella) in Algeria, by M^L J. D. Catta and A. Maige. — 

 On a case of sexual determinism produced by mixed grafting, by 

 M. A. Jurie. 



CONTENTS. 



PAGE 



Carnac and Stonehenge 465 



Our Book Shelf:— 



Zell : '■ Polyphem ein Gorilla."— W. L. H. D. . . 467 



Hall: " The Evolution of Consciousness " 467 



Knight : *' The Self-Educator in Chemistry." — A. S. 467 

 Letters to the Editor: — 



Density and Figure of Close Binary Stars. ( With 



Diagram. )— Dr. Alex. W. Roberts . . . 46S 



A Plea for a Prehistoric Survey of Southern India. — 

 Prof. A. C. Haddon, F.R.S. ....... 469 



The British Association at Glasgow . . 470 



Inaugural Address by Prof. Arthur W. Riicker, 

 Sec.R.S., President of the Association . ... 470 



Section A. — Mathematics and Physics. — Opening 

 Address by Major P. A. MacMahon, F.R.S. , 

 President of the Section ... ... . 477 



Section D. — Zoology. — Opening Address by Prof. J. 

 Cossar Ewart, F.R.S., President of the Section 482 



Notes 4SS 



Our Astronomical Column : — 



Opi^osition of Eros in 1903 49^ 



Radial Velocity of 1830 Groombridge 49' 



Nova Persei 49i 



Variable Radial Velocity of 5 Orionis 491 



Iron and Steel Institute 49' 



Relations between Climate and Crops. By H. B. 



Wren 493 



University and Educational Intelligence 495 



Societies and Academies 49^ 



NO. 1663, VOL. 64] 



