Benjamin Franklin's Numbers: An Unsung Mathematical Odyssey

Article excerpt

BENJAMIN FRANKLIN'S NUMBERS: AN UNSUNG MATHEMATICAL ODYSSEY by Paul C. Pasles Princeton University Press, NJ, 2008, 254 pages ISBN: 978-0-691-12956-3

It is well-known that Benjamin Franklin was an accomplished scientist, inventor, diplomat, writer, and publisher. But less commonly known is that he was also an applied mathematician with a fondness for what he called "magical squares" and circles. Below is the 8x8 Franklin Square. As is customary with these recreational puzzles, each row and column sums to the same value, in this case, 260.

But Franklin was not content with the customary. Notice that the shaded "bent diagonal" also sums to 260. This is also true of other "bent diagonals", as you are welcome to discover. In addition, Franklin designed his square so that each "half-row" and "half-column" sums to precisely half of 260. There are many more relationships hidden in this square, and Paul Pasles takes the reader on a grand tour of them in Benjamin Franklin's Numbers: An Unsung Mathematical Odyssey.

Pasles' book is a mathematical/biographical tour of the life and mathematics of Benjamin Franklin. His investigation looks for answers to many questions surrounding Franklin's interest in magic squares and circles. These include how Franklin first became interested in these; the people who were his magic square mentors, peers, and rivals; and how Franklin's magic numerical patterns were constructed. Although not a biography of Franklin, this book is a narrative that follows his life from beginning to end and includes the high points that have become part of American history: the lightning rod, bifocals, Poor Richard's Almanac, the Declaration of Independence, and Franklin's ambassadorial mission to France. …