about 1600. The title of Recorde’s book is a pun, based on
the Latin word cosa,used to represent unknown quantities in
algebra, Die Coss,the name of Christoff Rudolff’s algebra
book, and cos,which is Latin for “whetstone.” In this case,
Recorde suggests that the mathematics help sharpen the wit.1570 lRAFAELLO BOMBELLItranslates much of Diophantus’s
Arithmeticafrom Greek into Latin, but never publishes the
work.1572 lRafaello Bombelli is the first to suggest using symbols to
denote EXPONENTS.1583 lThomas Finck of Denmark invents the terms SECANTand
TANGENT.1586 lSIMON STEVINUSstates that objects of different weights fall
at the same rate, which is stated three years later by GALILEO
GALILEI.1591 lFRANÇOISE VIÈTEwrites In Artem Analyticam Isagoge,or
Introduction to the Analytical Art,establishing the basic
principles of algebra and leading to modern algebra notation.1593 lGalileo Galilei invents the first thermometer, a water and air
thermometer, to measure temperature.1600 lMathematicians begin to phase out the written word
aequalis,which we now write as EQUALS, replacing it with a
symbol. Consistent use of the equals symbol, =, as used
today, does not occur until some 80 years later.1609 lGalileo is appointed court mathematician and philosopher in
Florence by the Grand Duke of Tuscany.1610 lTHOMAS HARRIOTdiscovers sunspots and deduces the Sun’s
rotation based on his observations.lAfter nearly a lifetime of work, German mathematician
Ludolph Van Ceulen calculates the value of pi to 35 places
through the use of POLYGONs with 2^62 sides. As a result of
this phenomenal work, pi is often referred to as the
Ludolphine number.CHRONOLOGY 1570 – 1610
CHRONOLOGY 1570 – 1610