A perpetual calendar is one that shows the day of the week for any year, past, present, or future, you might want to look up. The 14 calendars show when any date falls from the year 1776 to the year 2000. Simply look in the index for the year of your choice and find the calendar number next to it.
Here’s an example of how it would work. Suppose you want to know on what day of the week New Year’s Day falls in the year 2000. Look in the index under 2000 and you find you have to check with calendar 14. Calendar 14 shows that January 1, 2000 falls on a Saturday.
Want to know when Christmas Day falls in the year 1985? Look in the index. 1985 refers you to calendar 3. Christmas Day, December 25, falls on a Wednesday.
Try it to find the day of the week on which you were born, or the day your parents were married, or the day the Declaration of Independence was signed.