Mathematical Treasure: Gaspar Lax’s Arithmetica speculativa and Proportiones

Gaspar Lax (1487–1560) was a Spanish mathematician and theologian. Most of his adult life was spent in Paris, where he studied and taught at theological colleges within the Sorbonne. Lax wrote several books on mathematics that recapped the work of previous scholars. For instance, his Arithmetica speculativa of 1515 was based on the work of Boethius. See the Index to Mathematical Treasures for several copies of Boethius’ arithmetic.

Book I of this text-heavy volume began with a list of the properties of numbers.

Lax also published a slim book on proportions in 1515.

Full digitizations of the copies of Arithmetica speculativa and Proportiones owned by the National Central Library of Rome are available in the Internet Archive.

Index to Mathematical Treasures