Ï.OGARITMETIQVE 9 Therefore it seems likely that Vlacq and De Decker must have "agreed" to suppress publication of the Nieuwe Tel-Konst, Part II, not only because it violated their contract but also because Vlacq must have shown that an "academic" version (in the style of Briggs' Arithmetica Logarithmica') would sell better than De Decker's competing "merchant-oriented" version. This proved right after all because logarithmic tables have never really taken off in the commercial world during the succeeding 300 years. A few copies (at least the one found in 1920) of De Decker's Nieuwe Tei-Konst, Part II, must have been printed, probably for sentimental reasons of De Decker, but the full set of tables printed by De Decker were bound into Vlacq's 1628 issue of Arithmetica Logarithmica, Part II (the print image of Vlacq's "Great Table" is exactly equal to the one in De Decker's publication). were indeed printed, but moved to England later, where the table pages were used in other books, like an English version of [6], published by George Miller in London, 1631. Title-page of the French edition of A. Vlacq's Arithmetica Logarithmica M Arithmétique Logaritmétique), Gouda, chez Pierre Rammasein, 1628. (Gouda, SAMH, Librije-coH. 508 G 4) attempted breach of contract, that he does not mention the contri bution by De Decker at all (while De Decker has always gracefully acknowledged Vlacq in his own L' books). Actually it suited Vlacq V""X^^sdè*t™^«NC well to pose as the only author, pubrvnitójufqucsi next to Napier and Briggs. The original intention was to publish the "Great Work" in three lan guages, but only Latin and French copies have survived. There are indications [11] that Dutch copies Fact 8 The full title of Vlacq's 1628 publication was Arithmetica Logarithmica, Editio 2, aucta per A. Vlacq, where "aucta" stood for the extension of the tables between 20,000 and 90,000. He included an abridged version of the extensive introduction by Briggs, carefully omitting his directions for calculation of logarithmic tables by the method of differences in the original Chapters XII and XIII. He also added a very useful table of trigonometric logarithms. Vlacq gives in his introduction due credit to Napier and Briggs, but he must have been so annoyed by De Decker's A CONSTRVCTION ET VSAGE dVNE TABLE CON TEN ANT hmbres de- DVNE AVTRE TABLE EN UoDclk font comprins les Logarithm® des Sinus, S-,?A'ABT U SB CF.S covnr Chez Pierre Rammnfcin. M.VC.XXVJII. f ARITHMETIQVE %u»nr S PRFMltREMENT TAX LJ1 TEMTS FASSfc

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Schatkamer | 2005 | | pagina 11