Perpetual calender display panel - has table of letters used with cursor on sheet bearing years months and days

摘要

The perpetual calender has two rigid sheets. Between them slides a cursor with the week days appearing in windows under the months. One sheet is for an ordinary and the other for a leap year. The device is based on any year having its Sunday letter taken from a table. The cursor is then fixed by an index under the letter and shows the day names below the days of the month. This then shows the complete year chosen. One face carries the Sunday letter for all years 1582 to 2799.