Perfected device for fast finding of the day of the week in which the centuries and the years corresponding to such centuries begin. (Machine-translation by Google Translate, not legally binding)

摘要

Improved device for rapid investigation of the day of the week in which the centuries and the years corresponding to those centuries begin, characterized in that it consists of an envelope in the form of a plan flask inside which a sheet can be introduced, by manual sliding, pre-eyed in one of the faces of the flask two windows through which the initials of the days of the week appear (engraved on the inner plate) in which the years of a century begin, which appear arranged in groups of columns under each of the windows, using one or the other window depending on whether the first year of the century is leap year or not; on the other side of the flask appear arranged in a column from the first century to the twelfth century indicating the day of the week in which the first year of that century began, whether that year was leap or not. (Machine-translation by Google Translate, not legally binding)