Julius Petersen

Julius Peter Christian Petersen (16 June 1839, Sorø, West Zealand – 5 August 1910, Copenhagen) was a Danish mathematician.

He started from very modest beginnings, and by hard work, some luck and some good connections, moved steadily upward to a station of considerable importance.

At his death –which was front-page news in Copenhagen– the socialist newspaper Social-Demokraten correctly sensed the popular appeal of his story: here was a kind of Hans Christian Andersen of science, a child of the people who had made good in the intellectual world.

He was taken out of school after his confirmation in 1854, because his parents could not afford to keep him there, and he worked as an apprentice for almost a year in an uncle's grocery in Kolding, Jutland.

The uncle died, however, and left Petersen a sum of money that enabled him to return to Sorø, pass the real-examination in 1856 with distinction, and begin his studies at the Polytechnical College in Copenhagen.

By that same year he had decided to study mathematics at the university, rather than to continue with the more practical second part of the engineering education.

In 1891 Petersen published a paper in the Acta Mathematica (volume 15, pages 193–220) entitled ‘Die Theorie der regularen graphs’.

one of these models was a ‘eine Serie von kinematischen Modellen’ which in 1888 was asked by ‘Verlagsbuchhandler L. Brill’ for permission to produce and sell.

In 1887 Petersen had constructed another model; a planimeter which was presented to the Royal Danish Academy of Science and Letters.

His last two years became a period of physical and mental debility, where, towards the end, he hardly had any memory left of his wide interests and the rich work which had filled his life.