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2020-12-18 20:09:06
Rabdologiae seu numerationis per virgulas libni duo
Andrew Hart, Edinburgh, 1617. NAPIER'S BONES. First edition, very rare, of one of the earliest mechanical calculating devices, using little rods of wood or ivory now known as 'Napier's bones'. Napier is best known today for his invention of logarithms, published in 1614 as Mirifici logarithmorum canonis decsriptio, the most important aid to calculation before the advent of mechanical and electronic calculators in the twentieth century. "In 1617 Napier's intense concern for the practicalities of computation led him to publish another book, the Rabdologiae, which contains a number of elementary calculating devices, including the rods known as 'Napier's bones.' These rods, which in essence constitute a mechanical multiplication table, had a considerable vogue for many years after his death. Each rod is engraved with a table of multiples of a particular digit, the tens and units being separated by an oblique stroke. To obtain the product 267 × 8, the rods 2, 6, 7 are assembled and the result is read off from the entries in the eighth row; thus gives 2,136. Book II is a practical treatment of mensuration formulas. Book III, the method of the promptuary, deals with a more complicated system of multiplication by engraved rods and strips, which has been called the first attempt at the invention of a calculating machine. The concluding section deals with a mechanical method of multiplication that was based on an 'areal abacus' consisting of a checkerboard with counters, in which numbers were expressed in the binary scale" (DSB). In this last section, Napier was one of the first to u … [Click Below for Full Description]
Bookseller: SOPHIA RARE BOOKS [Koebenhavn V, Denmark]
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