To Stockholm and Back - A Rediscovered Portrait of Karl Weierstrass

Karl Weierstrass
In the literature, one usually comes across the same old, well known portraits of important personalities of days gone by. Therefore, a hither to unknown, or perhaps forgotten, portrait of Karl Weierstrass [to the right], which I recently discovered, may well be of interest.

The one hundredth anniversary of the death of this famous Berlin mathematician is celebrated on 19th February 1997. It seems therefore appropriate to publish this picture in that journal, to which Weierstraß contributed for many years as an author and later as its co-editor.

The portrait was done in 1895 by the painter, designer and sculptor Conrad Fehr (1854-1933), when Weierstraß was already 80 years old. At that time, Weierstrass was confined to a wheelchair and no longer active. In that same year he could see the second volume of his collected works appearing. On his 80th birthday, Weierstrass sat in his chair and received tributes from students, friends and colleagues (but only for two hours, on the strict orders of his doctor). He showed signs of physical discomfort but was still quick-witted and reciprocated appropriately to the speeches made.

The painting was discovered in the following way: The oil painting of Weierstraß on his 80th birthday by R. von Voigtländer is well known (see [1]). However, it has only rarely been mentioned that Fehr too made an etching which was commissioned by students and friends of Weierstraß and presented to him on his birthday. In preparation for the coming centenary celebrations, I looked for this etching in the Mittag-Leffler Institute in Djursholm, Sweden but only found a photograph of a Weierstrass portrait, on which Fehr's signature was clearly legible. Was this the picture I was looking for? It didn't look like an etching. Although G. Mittag-Leffler had definitely received it at one time, the etching was nowhere to be found. I then heard that the copperplate etching gallery in Berlin does actually possess a portrait done by Fehr in 1895. This picture was published in [2] but without any mention of Fehr or the year 1895. It is, however, without doubt, the etching in question. The photograph in Djursholm, however, is of a quite different portrait. Fehr must have made two portraits - could the second be found anywhere?

And, sure enough, I found the original in the archives of the art collection at the Berlin-Brandenburg Academy of Sciences. It has been reproduced here after the photograph found in Djursholm (by kind permission of the Mittag-Leffler Institute). It is a pastel drawing dome in 1895 by Fehr (103 cm x 108 cm); some details which are no longer clear on the original (e.g. Fehr's signature) can, however, clearly still be seen on the photograph. The picture was exhibited in 1901 at the Great Berlin Art Exhibition (it was listed in the catalogue, but not depicted). In October of the same year, Fehr presented the picture to the Royal Prussian Academy of Sciences in Berlin."

- Reinhard Boelling (1997) -

Sources of the mentioned Weierstrass portraits:

[1] Cover picture of the Annual Report of the German Mathematical Society (DMV) 24 (1915).
Karl Weierstraß: Ausgewählte Kapitel aus der Funktionenlehre. Lecture, held in Berlin 1886. Published and commented by R. Siegmund-Schultze. (Teubner-Archiv zur Mathematik; 9.) Leipzig: Teubner 1988.