Simple mathematical problems can be intriguing, and since I have a bit more time on my hands than normal, I decided to see what sense I could make of a mathematical description first published in English in 1864. Many bow makers will be familiar with the brief section at the end of François-Joseph Fétis’s book ‘Notice of Anthony Stradivari,’ [1] in which he describes a method for graduating violin bows, told to him by Jean-Baptiste Vuillaume. The method works on the idea that