Exercise 289 of the Mathematischer Sinnen-Confect requires identifying a cuboid with integer sides and face diagonals of lengths 44, 117, 240 and 125, 244, 267. Paul Halcke, who published this challenge in his collection of 574 mathematical and astronomical problems, is recognized today for identifying this specific configuration, which is now classified as the smallest Euler brick.
Early Career and Institutional Influence
Born in 1662 in Elmshorn, Halcke established himself within the German mathematical community during the late seventeenth century. By approximately 1687, he held the position of writer and calculator at the city school of Buxtehude. His influence extended beyond the classroom in 1690 when he co-founded the Hamburgischen Kunst-Rechnungs lieb- und übenden Societät alongside Heinrich Meißner. This organization currently operates as the Hamburg Mathematical Society.
Twenty questions, eight minutes on the clock, and a percentile measured against everyone who has taken it. No sign-up.
Take the IQ test →The Mathematischer Sinnen-Confect
In 1694, Halcke authored a solution book to accompany exercises written by Heinrich Meißner. He later produced his own major publication, the Mathematischer Sinnen-Confect, which translates to mathematical mind candy. This text contained 574 exercises spanning the fields of mathematics and astronomy. The book was notable for its pedagogical approach, integrating mathematical solving methods with descriptive text and poetry. It served as a widely used textbook across multiple languages for over one hundred years following its release.
Calendar Production and Later Years
Beyond his academic contributions to geometry and number theory, Halcke worked as a computer and calendar maker. He edited several popular calendars during the eighteenth century, specifically for the years 1705, 1707, 1715, 1716, and 1725. He maintained his professional associations throughout his life, working alongside his brother, Johann Halcke, who was also a writer and computer. Paul Halcke died in 1731 in Buxtehude at the age of 69.
Fast facts
- Born: 1662, Elmshorn
- Died: 1731, Buxtehude
- Occupation: Mathematician, writer, computer, and calendar maker
- Notable work: Mathematischer Sinnen-Confect
- Co-founder: Hamburg Mathematical Society
- Smallest Euler brick sides: 44, 117, 240
Questions readers ask
What is an Euler brick?
It is a rectangular cuboid in which the lengths of the edges and the face diagonals are all integers.
What does the title Mathematischer Sinnen-Confect mean?
It translates from German to mathematical mind candy.



