]S!ov. 29, 1877] 



NA TURE 



ing a space between two clouds, leaving behind it a fiery track 

 of red. 



A Worcester correspondent gives the tirtie as 8.20. He 

 describes the colour as brilliant blue and orange, and behind 

 v*as a streaming trail of brilliant sparks, which remained visible 

 for a few seconds after the brighter light had disappeared. 



UNIVERSITY AND EDUCATIONAL 

 INTELLIGENCE 



Cambridge. — At a Congregation on November 22, Ihi; 

 University seal was ordered to be affixed to a letter of thanks to 

 his Grace the Chancellor of the University for his munificent 

 gift of a complete apparatus of scientific instratrtents for the 

 Cavendish Laboratory. 



A meeting of the members of the University to consider the 

 propriety of securing a personal memorial of Dr. Darwin, was 

 held on Monday in the combination room of Christ's College, 

 the Rev. Dr. Cartmell, Master of the College, presiding. It w^as 

 proposed by Prof. Humphry and seconded by Prof. Fawcett, 

 *' That it is desirable that^lhe University ghould.'possess a personal 

 memorial of Mr. Charles Darwin, LL.D." Proposed by Prof. 

 Newton and seconded by Mr. Piele, of Christ's, "That the 

 members of the University now present form themselv.es into a 

 committee, with power to add to their number, for the purpose 

 of collecting subscriptions from members of the University to 

 carry out the foregoing resolution." Proposed by Prof. Liveing, 

 seconded by Mr. J. W. Clark, " That Mr. A. G. Dew-Smith, 

 of Trinity College, be treasurer and secretary to the committee, 

 and be authorised to receive subscriptions." It was understood 

 that the memorial should assume the form of a portrait, and 

 about 75/. was subscribed in the room. 



Edinburgh. — The subscriptions to the Edinburgh University 

 Extension Fund now amount to 82,000/., and Government has 

 now promised to add 80,000/. to the amount on condition that 

 25,000/. is raised by public subscription, of which the sum of 

 10,000/. must be subscribed by December 31st next. The 

 University Professors at Edinburgh have already contributed 

 among themselves 5,360/. towards the additional 25,000/. 

 required. 



St. Andrews. — Lord Selborne has been elected Lord Rector 

 of this University. The students had much difficulty in getting 

 any eminent man to allow himself to be nominated, and it was 

 only on the day previous to the election that it was resolved to pit 

 Lord Selborne against the Right Hon. Gathorne Hardy. 



Prof. Alleyne Nicholson has been appointed Swiney Lecturer 

 on Geology by the Trustees of the British Museum. 



Leipzig. — Prof. Leuckhart^ the newly-elected Rector of the 

 University, was installed into the duties of the office on October 

 31, and delivered on the occasion an able addre3s " On the Deve- 

 lopment of Zoology up to the Present Time, and its Importance." 

 The students already nunber nearly 3,200, an attendance, as 

 usual, far above that of any other Garmin university. 



Amsterdam. — The new University of Amsterdam has lately 

 made a most flattering offer to Prof. Gegenbaur, of Heidelberg, 

 which has, however, been declined. 



Bergen. — It is intended to establish a new university in the 

 Norwegian tovvn of Bergen. Eighty thousand crowns liave 

 already been subscribed towards this object. 



SOCIETIES AND ACADEMIES 



London 



Mathematical Society, November 8.— Lord Rayleigh, 

 F.R.S., president, in the chair. — The following were elected to 

 form the Council during the session : — President : Lord Rayleigh, 

 F.R.S. Vice-Presidents: Prof. J. Cleik Maxwell, F.R.S., 

 Mr. C. W. Merrifield, F.R.S., Prof. H. J. S. Smith, F.R.S. 

 Treasurer, Mr. S. Roberts. lion. Secretaries : Messrs. M. 

 Jenkins and R. Tucker. Other members, Prof. Cayley, F.R.S., 

 Mr. T. Cotterill, Mr. J. W. L. Glaisher, F.R.S., Mr. H. Hart, 

 Dr. Henrici, F.R.S., Dr. Hirst, F.R.S., Mr. Kempe, Dr. 

 Spottiswoode, F.R.S., Mr. J. J. Walker.— Prof. Cayley made 



two communications, on the function <^ {x) = ^- "^ "^ , (a sin- 



cx -k- a 

 gttlarly neat expression was got for <^" (;ir), the late Mr. 



Babbage had considered the matter in 1813), and on the thcta 

 functions. — Mr. Tucker read a portion of a paper by Mr. Hugh 

 MacCoU (communicated by Prof. Crofton, F.R.S.) entitled the 

 calculus of equivalent statements. A short account of thi? 

 analytical method has been given in th? July and November 

 numbers (1877) of the Educational Times, under the name of 

 Symbolical Language. The chief u^e at present made of it is 

 to determine the new limits of integration when we change the 

 order of integration or the variables in a multiple integral, and 

 also to determine the limits of integration in questions relating 1 1 

 probability. This object, the writer asserts, it will accomplislj 

 with perfect certa'nty, and by a process almost as simple and 

 mechanical as the ordinary operations of elementary algebra. — 

 The president read a paper on progressive waves. It has often 

 been remarked that when a group of waves advance ititiJ still 

 w^ter the velocity of the group is less than that of the individual 

 waves of which it is composed ; the waves appear to advance 

 through the group, dying away as they approach its anterior 

 limit. This phenomenon seems to have been first explained by 

 Prof. Stokes, who regarded the group as formed by the super- 

 position of two infinite trains of waves of equal amplitudes and 

 of nearly equal wave-lengths advancing in the same direction. 

 The writer's attention was called to the subject about two years 

 since by Mr. Froude, and the same explanation then occurred to 

 him independently. In his work on " The Theory of Sound " 

 (§ 191), he has considered the question more generally. In a 

 paper read at the Plymouth meeting of the British Association 

 (afterwards printed iii Nature), Prof. Osborne Reynolds gave 

 a dynamical explanation of the fact that a group of deep-water 

 waves advances with only half the rapidity of the individual 

 waves. Another phenomenon (also mentioned to the author by 

 Mr; Froude) was also discussed as admitting of a similar expla- 

 nation to that given in the present paper. A steam launch 

 moving quickly through the water is accompahied by a peculiar 

 system of diverging waves, of which the most striking feature is 

 the obliquity of the line containing the greatest elevation of 

 successive waves to the wave-fronts. This wave-pattern may be 

 explained by the superposition of two (or more) infinite trains of 

 waves, of slightly differing wave-lengths, whose direction and 

 velocity of propagation are so related in each case that there is 

 no change of position relatively to the boat. The tilode of com- 

 position will be best understood by drawing on paper two sets of 

 parallel and equidistant lines, subject to the above Conditions, to 

 represent the crests of the component trains. In the case of twj 

 trains of slightly different wave-lengths, it may be proved that the 

 tangent of the angle between the line of maxima and the wave- 

 fronts is half the tangent of the angle between the wave-fron!s 

 and the boat's course. — Prof. Clifford, F.R.S., communicated 

 three note', (i) On the triple generation of three-bar curves. // 

 one of the three-bar systems is a crossed rhomboid, the other two are 

 kites. This follows from the known fact that the path of the 

 moving point in both these cases is the inverse of a conic. Bat 

 it is also intuitively obvious as soon as the figure is drawn, and 

 thus supplies an elementary proof that the path is the inverse of 

 a conic in the case of a kite, which is not otherwise easy to get. 

 (2) On the mass-centre of an octahedron. The construction was 

 suggested by Dr. Sylvester's construction for the mass centre of 

 a tetrahedral frustum. (3) On vortex-motion. The problfem 

 solved by Stokes as a general question of analysis, and subse- 

 quently by Helmholtz for the special case of fluid motion may be 

 stated as follows : given the expansion and the rotation at evfery 

 point of a moving substance, it is required to find the velocity at 

 every point. The solution was exhibited in a very simple form. 



Zoological Society, November 6. — Mr, X. Grote» vice- 

 president, in the chair. — A letter was read from Mr. R. Trimen, 

 containing remarks on the African species of Sarcidiornis. —A 

 letter was read from Mr. A. O. Hume, containing some remarks 

 on Mr. Howard Saunders' recent p.iper on the Sterninae. — The 

 secretary exhibited, on the part of Mr. Geo. Dawson Rowley, 

 an egg of Pauxis galeata, laid by a black female. — Prof. W. II. 

 Flower, F.R.S,, read a paper entitled "A Further Contribution 

 to the Knowledge of the existing Ziphioid Whales of the Genus 

 Mesoplodon, containing a Description of a Skeleton and several 

 Skulls of Cetaceans of that Genus from the Seas of New Zea- 

 land." — A communication was read from Lieut. -Col. R. H. Bed- 

 dome, containing the descriptions of three new species of reptiles 

 from the Madras Presidency. These were proposed to be called 

 Oligodon travancoricum, GymHedactylusjeyporensis, and Bufo tra- 

 vancoriiUs. — A communication was read from the Marquis of 

 Tweeddale, F.R.S., containing an account of a collection of 



