Saturday, December 1, 2012

Francesco Ghaligai's Practica D'Arithmetica

These pages are from the 1552 edition of the Practica d'Arithmetica of Francesco Ghaligai (d. 1536). On these pages, Ghaligai proposes a new notation for powers of the unknown. Notice on the left hand page that his notation for the second power (censo) is just a square, but the other notations never caught on with other authors. On the right hand page, Ghaligai illustrates the notation by calculating the powers of 2 up to the fifteenth power.

Practica d'Arithmetica was originally published in 1521, but this printing, like several other printings, is identical with the original. Its intended audience was merchants, so there are many practical problems dealing with issues of trade.  In the sections on algebra, Ghaligai introduces his own notation.