“Vertheidigung der Hahnschen Rechnungs-Maschine gegen einige Misverständnisse, welche man zum Nachtheil derselben, theils aus der...
8vo, cont. speckled boards, some foxing. Weimar: [1785].
Dated 1 October 1784, this is one of only two accounts in print by Hahn — the first appeared earlier in the decade in the same journal — of his famous cylindrical calculating machines; they were the first fully functional and well-known four-species mechanical calculating machines. In this article, Hahn accuses Johann Helfrich Müller (1746-1830), of stealing his designs in order to manufacture a very similar machine.
Hahn (1739-90), a German vicar, had a great interest in mechanics and mathematics. He designed a number of clocks and astronomical machines and wrote books... More