8vo, cont. speckled boards, some foxing. Weimar: .
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 about improved time-keeping devices. He began to design a calculating machine in 1770 as an aid to his manufacturing of clocks and planetariums. During his lifetime, he managed to construct about ten of these machines, of which only two survive today. He was clearly aware of the machines of Leibniz and Leupold but made many improvements; his are significantly different from those of his predecessors. Following his death, his son and others constructed more of these calculators, which enjoyed considerable popularity in Germany in the end of the 18th century.
Müller clearly used the basic design of Hahn’s machine but made a number of improvements; they led to his development of a difference engine almost forty years before Charles Babbage. At the end of Hahn’s article, he states that he has three calculators for sale and that if anyone wants to pay 100 thaler, they can buy them as a group.
Fine copy of the first two issues (of four) of Der Teutsche Merkur of 1785.
❧ Much of our description is based on the wonderful History-Computer website.
Item ID: 6889