One day Professor Weierstrass was rather surprised to see a young lady present herself before him, asking to be admitted as his pupil in mathematics. The Berlin University was, and still is, closed to women, but Sonia's ardent desire to be taught by the man who was generally acknowledged to be the father of modern mathematical analysis, made her apply to him for private lessons.
Professor Weierstrass felt a certain distrust in seeing this unknown female applicant; however, he promised to try her, and gave her some of the problems which he had set apart for the more advanced pupils in the seminary for mathematics. He felt convinced that she would not be able to solve them, and forgot all about her, the more so as her outward appearance on the first visit had left no impression at all upon his mind. She never dressed well, and on this occasion she wore a hat which hid her face completely, and made her look very old, so that Professor Weierstrass, as he told me himself, after having seen her for the first time, had neither the slightest idea of her age, nor of her unusually expressive eyes, which used to attract everybody at first sight. A week later she called again, and said that she had solved all the problems. He did not believe her, but asked her to sit down beside him, after which he began to examine her solutions one by one. To his great surprise everything was not only correct, but very acute and ingenious. Now in her eagerness she took off her hat and uncovered her short curly hair; she blushed at his praises, and the elderly professor felt something like fatherly tenderness towards this young woman, who possessed the divination of genius to a degree he had seldom found, even in his more advanced male pupils. And from that moment the great mathematician became her friend for life, the most faithful and helpful friend she could wish. In his family she was received as a daughter and sister.
It was her great object to find the logical connection between all manifestations of life, as for instance, between the laws of thought and the outward phenomena. She could not satisfy herself with seeing in part, and understanding in part; it was her delight to dream of a more perfect form of life, where, according to the apostle, "we shall see no longer in part, but face to face." To see the unity in the variety was the aim and end of all her philosophy and her poetry.
Has she reached this end now? Our thought cannot fathom this possibility, but our heart beats with a trembling hope which breaks the point of death's bitterness.
Besides, she had always wished to die young. Though hers seemed an inexhaustible well of life, ready for every new impression, open to every joy, great or small, in the innermost recess of her heart there was a thirst, which this life could never satisfy. As her mind craved absolute truth, absolute light, so her heart craved absolute love - a completeness which human life does not yield, and which her own character in particular rendered impossible. It was this discord that consumed her. If we start from her own belief in a fundamental connection between all phenomena of life, we see that she was bound to die, not because some strong and destructive microbes had settled in her lungs, or because the chances of her life had not brought her the happiness she desired, but because the necessary organic connection between her inward and outward life was missing; because there was no harmony between her thought and her feeling, her temperament and her character.