A birthday present

Abstract

There was no doubt about its genuineness. This was indeed the album Weierstrass mentions in a letter to Sonya Kovalevskaya written just over 100 years ago, on 14 December 1885, in which he writes about the celebration marking his seventieth birthday: "The album for the photographs (more than 500 of them) is a magnificent work, which met with general acclaim" ([1], p. 129). On 44 pages there are a total of 294 photographs of about the same format--seven of them to a page, with a few gaps in be tween--showing pupils, friends, and colleagues of Weierstrass from many countries in Europe, including renowned university professors, masters, headmasters , high school teachers, post graduate students, and undergraduates (including such names as L. Heffter, A. Gutzmer, and G. Wallenberg). Particularly conspicuous among the photographs is that of the only woman, his pupil Sonya Kovalevskaya (Figure 2), with whom he maintained a very close friendship until her untimely death in 1891. The photographs are arranged essentially according to country (in the German section, the photographs are grouped mostly according to university and region). One finds photographs of such people as (in the order of their appearance in the album) G. Zeuthen, A. Cayley (Figure 3), E. Picard, F. Casorati, Hj. Mellin, E. Phragm6n, S. Lie (Figure 4), L. Sylow, L. Schl/ifli, F. Schottky, G. Frobenius (Figure 5), C. Runge, R. Lipschitz, P. Gordan, M. Noether, J. Li~roth, L. Stickelberger, M. Pasch, H. A. Schwarz (Figure 6), O. H61der, A. Schoenflies, G. Cantor (Figure 7), M. Cantor, M. Planck (Figure 8), A. Hurwitz (Figure 9), F. Klein (Figure 10), F. Schur, H. Weber, A. Pringsheim, A. Brill, O. Schl6milch, and P. du Bois-Reymond, to name but a few of the prominent mathematicians and physicists.