John Napier’s Rabdologia originally appeared in Latin at Edinburgh in 1617. Only now for the first time an English translation is published. The edition is introduced by R. E. Rider. By the beginning of the seventeenth century, pressures for computational dexterity were coming from several quarters: commerce, navigation, astronomy. Mathematicians were spurred to devise instruments and techniques for reducing the labor and simplifying the procedures involved. In even the rudimentary operations of arithmetic, instrumental assistance was welcome. In response to these desiderata Napier composed the Rabdologia. In his book he describes three mechanical devices for calculation. Especially the first, the so-called Napier’s rods, attracted considerable attention and enjoyed some popularity throughout the seventeenth century and some notice even in the first half of the eighteenth century. Other authors included in their own arithmetic texts accounts of, and sometimes improvements on, Napier’s rods. Appealingly simple in their conception, they did succeed in reducing multiplication, division, and extraction of square and cube roots to easier problems of addition and multiplication. The other devices proposed by Napier did not meet any success. The full title of Napier’s treatise is: Rabdologiae, seu numerationis per virgulas libri duo: Cum appendice de expeditissimo multiplicationis promptuario. Quibus accessit et arithmeticae localis liber unus. This is translated as: Rabdology or calculation with rods in two books with an appendix on the high-speed promptuary for multiplication and one book on location arithmetic. Book 1 describes a set of rods inscribed with numbers forming multiplication tables, and explains how to use them. Book 2 offers tables, examples, and general problems demonstrating the utility of the rods in solving questions of geometry and mechanics. In an appendix Napier describes the second of his mechanical devices for calculation. This one uses strips stored in a box. It is a forerunner of the modern calculating machine, but in fact less useful than the rods, for it will only multiply. The third device, described after this appendix, is a combination of a chessboard and counters with binary arithmetic.
Reviewer: P.Bockstaele (MR 92f:01043)