O.E. van Poelje
Introduction
3
The history of logarithms has by now progressed to a state where the logarithm is
just one of the few hundred items in a standard book of mathematical functions.
How different it used to be during the past few centuries, when the logarithmic
table was a powerful "calculating instrument"! And how fast this shining
computational miracle has been eclipsed - together with the slide rule - by the
electronic calculator of the 1970's. When Henry Briggs (1560-1630) took over
from John Napier (1550-1617) the concept and further tabulations of the
logarithm in 1615, he was to start a revolution in the computing of multiplications,
divisions and powers by the usage of logarithmic tables. However, three other
men have created in the 1620's their own contributions to the early Briggian
tables:
Adriaen Vlacq and Ezechiel de Decker: Dutch
Contributors to the early Tables of Briggian
Logarithms1
Edmund Gunter (1581-1626), Professor of Astronomy since 1619 at Gresham
College, London, and very involved in navigation at sea. He was a good friend of
Briggs who has been Professor of Geometry at the same college;
Ezechiel de Decker (1603-1647), who was from 1621 to 1629 a teacher of
geometry and arithmetic - especially for commerce and accounting - and surveyor
in Gouda. This city was part of Holland, one of the seven provinces in the
"Republiek van de Vereenighde Nederlanden" (Republic of the United
Netherlands);
Adriaen Vlacq (1600-1667), born in Gouda from a
family of merchants and magistrates, well educated
at the Latin School but without a University degree.
In his early twenties he became entranced by
mathematics, and he probably met De Decker while
educating himself in the art of arithmetic and
geometry.
Possible coat of arms of the V/acq family
(reconstructed by J. EJ. Geselschap)
1 Dit artikel verschijnt ook in Journal of the Oughtred Society, Vol. 14, No. 1 (Spring 2005). Met
toestemming van de auteur mogen we het in De Schatkamer opnemen. De tabellen zijn
oorspronkelijk, de overige afbeeldingen zijn door de redactie van De Schatkamertoegevoegó.
De verwijzingen tussen vierkante haken in de tekst zijn naar de "References and Notes" aan het
eind van het artikel.
