June 30, 1892] 



NATURE 



203 



for the insurance against fire. But assumes no responsibility 

 ■either for damage or for loss of articles, 



IV. Those who desire to exhibit under closed cases must do 

 so at their own expense. 



V. The charge of transport (to Niimberg) and, if desired, 

 the insurance of transport is at the expense of the exhibitor. 

 In what refers to the return transport, by the courtesy of the 

 directors of the Bavarian and the other main lines of German 

 railways free transport is guaranteed for all unsold objects of the 

 exhibition. All expense of home-transport beyond this border 

 is at the expense of the exhibitor. 



VI. An explanatory detailed catalogue of the mathematical 

 exhibition is to be issued. . 



The first part will consist of essays, having reference to prob- 

 lems, results, and methods of geometrical representation. 



The second part of an enumeration of all articles exhibited 

 in connection with detailed theoretical descriptions. Here, if 

 desired, the prices may be added. This part of the catalogue 

 will be fully illustrated to give a vivid impression of the exhibited 

 articles. We respectfully request all institutes, publishers, &c. , 

 to forward woodcuts, clichh, &c., which may be inserted in 

 the text. 



An appendix to the catalogue will be published, including all 

 advertisements which may hereafter serve as a directory for all 

 those interested. ^ 



VII. As far as possible all technical explanations of the 

 articles will be undertaken by the committee. 



VIII. The committee will attend to all sales and buyings 

 <which are in view by various mathematical institutes of our 

 Hochschulen) and give all desired information. 



During the exhibition the sold articles must not be removed 

 from the exhibition rooms, except with special permission of the 

 committee. 



IX. The intention to participate in the exhibition may be 

 given by the use of the "Exhibition Announcement" until 

 July I. Address : Herrn Prof. Dr. Walther Dyck, MUnchen, 



Hildegardstrasse \\. 



At the same time all papers and scientific notices for the 

 catalogue respecting woodcuts and cliches for illustration must 

 be sent to the same address."' 



The editors reserve the right of all abbreviation and change in 

 the notes of Part 2 of the catalogue that the uniformity may 

 require. 



X. All articles proposed for exhibition must be forwarded 

 from September i to 7, under the address : Mathematische 

 Ausstelluug in Niirnberg (Bayern), zu Handen der Herren 

 Danler and Co. 



The return of all articles will be effected within two weeks 

 after the close of the exhibition under the conditions fixed 

 above (No. V.) 



XI. For nearer information in /espect to the intentions and 

 the extent of the exhibition we annex a preliminary classification 

 of the articles. 



I, Geometry. Theory of Functions. 

 Models employed in elementary teaching of geometry (solid 

 geometry, trigonometry, descriptive geometry). 



Polyhedra. Division of surfaces and spaces in polygons 

 respecting polyhedra. 

 Plane curves. 



Curves in space. Developable surfaces. 

 Surfaces of the second order. 

 Higher algebraic surfaces. 

 Transcendental surfaces. 

 Models illustrating geometry of complexes. 

 ,, ,, curvature of surfaces. 



,, ,, theory of functions. 



,, ,, analysis situs. 



2. Arithmetic, Algebra, Integral Calculus. 



Calculating machines. Slide rules. 



Instruments for solving equations and for construction of 

 functional relations. 



I The fees for insertion in the appendix are 30 Reichsmark for the whole 

 page (great 8"), 18 R.-M. for i page, 10 R.-M. for \ page, 5 R.-M. for \ 

 page. 



* All advertisements for the Appendix and payments for same must not be 

 <ieferred later than August i, to the same address, Prof. Dyclc. 



NO. II 83, VOL. 46] 



Curvometers, planimeters, integrating machines, instiumer.ls 

 for solving differential equations. 



3. Mechanics. Mathematical Physics. 



Models employed in elementary teaching. 



Kinematics. Machines for description and transformation of 

 curves and surfaces. Pantographs, perspectographs. 



Apparatus for demonstration of mechanical principles. 



Equilibrium and motion of a point. 



Poinsot motion of a rigid body ; precession, nutation ; 

 dynamical tops, gyroscopes. 



Models and articles showing the effect of stress flexion and 

 torsion of solids. 



Elastic properties of solids (especially of crystals). 



Hydrodynamics. 



Geometrical representations and mechanical apparatus illus- 

 trating physical phenomena (for ex. vibrations, wave-motion, 

 propagation of sound and light. Thermodynamic and electro- 

 dynamic phenomena). 



XII. It is understood that the exhibitors declare their 

 willingness to submit to the present rules and further dispositions 

 ordered by the committee for the interest of the exhibition. 



For all further information please address the undersigned 

 delegate of the committee. 



Prof. Dr. Walther Dyck, 

 MUnchen, Hildegardestrasse i^. 



For the purpose of collecting and forwarding objects of 

 interest, a Committee has been formed consisting of Lord 

 Kelvin (Chairman), Lord Rayleigh, Profs. Svlvester, O. J. 

 Lodge, G. F. Fitzgerald, W. G. Adams, Sir R. Ball, A. A. 

 Common. Secretaries : A. G. Greenhill, O. Henrici. 



The Secretaries will forward prospectuses and forms of 

 application to intending exhibitors, and will take charge 

 of objects at the Central Institution, Exhibition Road, 

 South Kensington, S.W., and forward the objects at the 

 proper time to Niirnberg, unless forwarded direct by 

 the exhibitors. 



THE KEKULlt FESTIVAL AT BONN. 



ON June I a remarkable demonstration took place at 

 the University of Bonn. The occasion was the 

 twenty-fifth anniversary of the call of August Kekule to 

 the Professorship of Chemistry at that University. The 

 details, which we have taken chiefly from the Kolnische 

 Zeitung, will be of interest to the student of chemistry, 

 and probably of value to the future historian of the 

 science. 



The ceremony began in the morning with an enthusi- 

 astic ovation on the part of the students. The chemical 

 theatre was decorated with plants ; on the blackboard 

 figured the benzene hexagon, made up with garlands of 

 flowers, in the midst of which appeared the letters A. K. 

 as a monogram of roses. At the usual lecture hour Prof. 

 Kekul^ entered, and was greeted with great enthusiasm. 

 One of the chemical students, Alfred Helle, delivered a 

 graceful address, in which he congratulated his fellows 

 on being privileged to sit at the feet of the greatest of 

 living chemists, ending by calling for three cheers for the 

 Professor, in which the audience heartily joined. 



Prof. Kekule then addressed the students, detailing with 

 characteristic humour some passages in his life. He was, 

 he said, a pupil at the Darmstadt Gymnasium, where he 

 chiefly devoted himself to mathematics. He was destined 

 by his father for the profession of architect, and some 

 houses still existed in Darmstadt, the plans of which he 

 had drawn when a youth at the Gymnasium. At Giessen, 

 where he went to study architecture, he attended Liebig^s 

 lectures, whereby he was enticed to chemistry. But his 

 relations would not at first hear of his changing his pro- 

 fession, and he was given half a year's grace to think over 

 it. He spent this time at the Polytechnicum at Darm- 



