De viribus quantitatis
|De viribus quantitatis|
The book has been described as the "foundation of modern magic and numerical puzzles", but it was never published and sat in the archives of the University of Bologna, seen only by a small number of scholars since the Middle Ages. The book was rediscovered after David Singmaster, a mathematician, came across a reference to it in a 19th-century manuscript.
It contains one of the first reference to card tricks as well as guidance on how to juggle, eat fire and make coins dance. It is the first work to note that Leonardo was left-handed.
De viribus quantitatis is divided into three sections: mathematical problems, puzzles and tricks, and a collection of proverbs and verses.