Gemowe lines
Posted on Friday 9 March 2007
Inspired by an item over at languagehat which cited the Earliest Known Uses of Some of the Words of Mathematics (an item, by the way, in which I left way more comments one-after-the-other than any decent person would consider to be good netiqette), I did a little digging around and found an interesting article on the earliest known uses of mathematical symbols.
A favourite quote of mine is from Robert Recorde who invented the equals sign and which he introduced in his textbook The Whetstone of Witte in 1557:
To avoide the tediouse repetition of these woordes : is equalle to : I will sette as I doe often in woorke use, a paire of paralleles, or Gemowe [twin] lines of one lengthe, thus: =, bicause noe .2. thynges, can be moare equalle.
The title of his book The Whetstone of Witte is a play on words. The unknown quantity to be solved for in algebra was called a "coss" (from the Italian "cosa" which derived from the Arabic "shai" meaning "a thing") and algebraists at that time were known as cossists. The word "cos", on the other hand, is Latin for whetstone,
a stone used for sharpening knives. Hence we have a pun: here is a textbook on
algebra which will sharpen your wits. Okay, geddit?
|
In the same book, Recorde also introduced the symbols for plus and minus into English mathematical notation:
There be other 2 signes in often use of which the first is made thus .+. and betokeneth more: the other is thus made .-. and betokeneth lesse.and the word subtract (see the original languagehat post):
Wherfore I subtract 16. out of 18.
