Saturday, November 19, 2011

Ghisi's Labrythine Legacy

Still More Fragments of History Recovered

When last we visited Ghisi's Labyrinth, Mariano Tomatis had introduced two more variations on the book: Pastime, pre-dating the 1607 edition, and Devotion of the Lord, subsequent to the 1616 edition. A video by Bill Kalush illustrated how the latter trick worked in practice. Two months ago, Mariano posted The Map of Andrea Ghisi's Laberinto which, in addition to detailing the design and operation of the trick, also introduced yet another variation: La Zecca Aritmetica, by Francesco Gattici.

In 1613 viscount Francesco Gattici published La Zecca Aritmetica con mirabile secreto at the Venetian typographer Giacomo Sarzina. This book shares the same structure of Laberinto, with some interesting differences. Printing Gattici's book was cheaper because there are no figures in it: its 1260 squares show only three distinct series of words. Using the book, the player may choose between three different divinations: the currency of a coin, the name of its owner or the city he lives in. Every square contains the name of currency, the last name of a person and the name of a city.

This additional title can be added to the Ghisi family tree.

1603 Pastime: The openings show four 13-image matrices, arranged vertically. There are a total of 74 images used, although only 52 which are operative. Some of the images are merely misdirection, tending to conceal the actual design of the trick.

1607 Labyrinth: The openings show four 15-image matrices, arranged horizontally. There are a total of 60 images used. This book was dedicated to Prince Gonzaga of Mantua.

1610 Labyrinth: This was an English translation of the 1607 book.

1613 La Zecca Aritmetica: Ghisi's famous picture book functions just as well without any pictures, driving a stake through the heart of some New Age fantasies.

1616 Labyrinth: The openings also show four 15-image matrices for a total of 60 images used. Most of these (45) were based on the E-Series model book, some were repeated from the earlier edition, and some were new. This book was dedicated to Doge Bembo of Venice.

1617 Devotion of the Lord: The openings also show four 15-image matrices for a total of 60 images used. The images include well-known saints, different aspects of the Virgin, (such as the Virgin of Loreto), named archangels, a few biblical figures, and one square with a crown and lilies, with the words, Dignare me laudare te, Virgo sacrata. Da mihi virtutem.

Today Mariano has posted the slide show of a presentation he made to the CICAP Conference last week. The slides present a different approach to understanding the design of Ghisi's parlor trick and its place in the larger history of mathematical recreations.

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