De Arithmetica

Title: De Arithmetica
Author: Ioannis Caramuelis (Juan Caramuel y Lobkowitz)
Year: E48
Subject: Very early exposition of dozenal.
http://www.dozenal.org/drupal/sites_bck/default/files/DSA_lobkowitz_duodenaria.pdf
In a time in which "astronomy" and "mathematics" were nearly synonymous among Europe's educated elite, Ioannis Caramuelis, known more commonly by his Spanish name Juan Caramuel y Lobkowitz, penned this brief but brilliant defense of dozenal in the universal language of the time, Latin. The earliest discussion of dozenal yet known (having been written in E48 (1640)), Lobkowitz uses "p" for ten (the digits "1" and "0" combined) and "n" for eleven (two digit "1"s connected by a swash at the top). He explains and demonstrates the four arithemtic functions, including both a "basic" and "advanced" division (corresponding to our "short" and "long" division), and urges the adoption of the dozenal system in astronomy. A brilliant work, very much ahead of its time; provided here in its original Latin, with parallel English translation.