August 26. 1S97] 



NA TURE 



395 



If we take the simplest case first, that of minimum 

 sunspots depending upon minimum solar activity, we 

 then get chiefly a well-developed equatorial elongation 

 with a marked absence of irregular streamers in mid- 

 latitudes. In support of this, I append two drawings 

 (Figs. 22, 23) made at the eclipses which took place in 

 the years 1867 and 1879, years of sunspot minimum. 

 In the second drawing, made by Prof. Newcomb, the 

 disc is shown by which he eclipsed the brighter lower 

 reaches of the corona, so as to give his eye the best 

 chance of seeing feeble e.xtensions. The pole supporting 

 the disc was vertical, but it is shown slantwise in the 

 illustration because it is most important to show the sun's 

 axis upright. 



At the minimum period not only are these extensions 

 best seen, but the exquisite structure near the sun's poles 

 is very strikingly revealed. 



At and near the maximum all this is changed, and we 

 get streamers and their separating rifts very irregularly 

 distributed. In 1896 these irregular streamers form 

 striking objects, and we know from the sunspot observa- 

 tions that the atmosphere was more than usually dis- 

 turbed—more than might have been anticipated, seeing 

 that the maximum was due to occur in 1892. 



I am glad to find in the valuable collection of Russian 

 memoirs to which I have referred an important paper by 

 M. Hansky, calling attention to the way in which the 

 form of the corona varies with the sunspot period. His 

 studies entirely confirm all 1 have written on this subject. 

 Norman Lockyer. 



THE INTERNATIONAL CONGRESS OF 

 MA THEM A TICIANS. 



ON August 9, 10 and 11, the first International Con- 

 gress of Mathematicians met in Zurich. By the 

 morning of the 9th there were in attendance 200 members 

 from all parts, viz. : from Switzerland, 53 ; Germany, 40 ; 

 France, 25 ; Italy, 19 ; Russia, 18 ; Austria Hungary, 

 16; United States, 7; Sweden, 6; Denmark, 4 ; Belgium, 

 England, Holland, 3 each ; Greece, Portugal, Spain, 

 I each. The gathering, while fairly representative of the 

 different branches of pure mathematics, did not adequately 

 represent applied mathematics. The meeting of the 

 British Association in Toronto was doubtless responsible 

 for the absence of many English mathematicians, who 

 might otherwise have been at Zurich ; but, even making 

 allowance for this, the presence of three representa- 

 tives of English mathematics can hardly be regarded 

 as a sufficient recognition of the importance of the 

 congress. 



The regulations, while prescribing French and German 

 as the official languages, make provision also for the use 

 of English and Italian ; and it is expressly laid down that 

 in the appointment of the committee these languages 

 shall be represented. This body, elected at the first 

 general meeting, was therefore composed as follows : — 

 President, Prof Geiser ; Secretaries, MM. Franel and 

 Rudio ; Hon. Secretaries, MM. Borel, Pierpoint, Volterra, 

 E.V.Weber; Members, MM. Brioschi, llobson, Klein, 

 Mertens, Mittag-Leffler, Picard, Poincare (absent;, H. 

 Weber. The principal office of the committee was to 

 formulate the objects and methods of the series of con- 

 gresses, and to give a preliminary consideration to certain 

 matters with respect to which action must be taken by 

 the next congress, to be held in Paris in 1900. Among 

 these matters those of most pressing importance are the 

 adoption of some scheme of classification of the various 

 branches of mathematics, and the undertaking of some 

 bibliographical work. As to the organisation of the series 

 of congresses, it is decided that these shall meet in 

 different countries at intervals of from three to five years. 

 The advisability of giving continuity to the series by the 



NO. 1452, VOL. 56] 



establishment of some permanent central body is affirmed, 

 but action is deferred ; this question will doubtless be 

 ripe for discussion in 1900. The most tangible object of 

 the congress is the encouragement of the production of 

 detailed reports on different branches of mathematics, 

 for which so admirable a model is afforded by the Brill- 

 Noether " Bericht iiber Funktionen-theorie," published 

 three years ago. Doubtless, too, the preparation of such 

 reports will be materially assisted, and their international 

 character secured, by the furthering of personal relations 

 among mathematicians of different countries, which is 

 laid down as one object of the congress. The arrange- 

 ments so admirably planned and carried out by the Ziirich 

 committee of organisation gave all possible facilities for 

 social intercourse, beginning with an informal gathering 

 on the evening preceding the actual meetings, and in- 

 cluding afternoon excursions on the lake and to the top 

 of the Uetliberg. 



Tuesday was given up to the reading of papers, for 

 which five Sections were organised, each with President, 

 Vice-President, and Secretary, (i) "Arithmetic and 

 .Algebra," Mertens, Peano, Amberg ; (2) " Analysis and 

 Theory of Functions," Picard, Brioschi, Jaccottet ; (3) 

 "" Geometry," Reye, Segre, KUnzler ; (4) " Mechanics 

 and Mathematical Physics,'' Jung, Joukowsky, Flatt ; (5) 

 " History and Bibliography," Moritz Cantor, Laisant, 

 Schoute. The sittings of these Sections were arranged 

 to begin at different hours of the morning and afternoon, 

 to meet the natural desire of members to hear as many 

 as possible of the leaders in different subjects. Papers of 

 special interest were those of Brioschi, " Sur une classe 

 d'equations du cinquieme degre"; Picard, "Sur les 

 fonctions de plusieurs variables" ; Reye, " Neue Eigen- 

 schaften des Strahlenkomplexes zweiten Grades " ; H. 

 Weber, " Ueber die Genera in algebraischen Zahl- 

 kcirpern"; Zeuthen, "Isaac Barrow et la mithode in- 

 verse des tangentes." Moreover, addresses were delivered 

 at the opening and closing general meetings on Monday 

 and Wednesday mornings by Poincare, "Sur les rap- 

 ports de I'analyse pure et de la physique mathematique" ; 

 Hurwitz, " Entwicklung der allgemeinen Theorie der 

 analytischen Funktionen in neuerer Zeit"; Peano, 

 " Logica Matematica" ; Klein, "Zur Frage des hoheren 

 mathematischen Unterrichles." In the much-regretted 

 absence of M. Poinc.ire, his address was read by M. 

 Franel. 



Among the m ithematicians present, in addition to 

 those already named, were M.\I. Brill, Noether, G. 

 Cantor, Dyck, Gordan, Korteweg, Larmor, F. Meyer, 

 Osgood, Vassilief, Veronese, Enriques, Enestrom. 



1 



THE BRITISH ASSOCIATION. 

 HE Toronto meeting of the British Association 

 opened on Wednesday in last week, and came to 

 an end yesterday, as we went to press. The reports 

 which have reached us show that the meeting has been 

 a successful one throughout, both from a social and also 

 from a scientific point of view. .\s in 1884, when the 

 Association met in Montreal, Canadians have shown by 

 the entluisiastic reception given to the memb-rs that 

 they value agencies which exist for the diffusion of 

 knowledge and culture. The many papers read before 

 the Sections by no means represent the whole result of 

 such a gathering. The Dominion has been bound closer 

 to the mother country, the interests of science have been 

 brought before the notice of the public, and scientific 

 kno\vledge will be advanced by the opportunity which the 

 meeting has given for the exchange ot ideas. The Mon- 

 treal meeting of the Association was not only of value 

 in assisting scientific education and research in Canada, 

 but our Transatlantic contemporary — Science — acknow- 

 ledges that it gave a considerable impulse to science 



