At an antique auction, one of the items that came up for sale was a child's sled. It was a hand-made sled, a wooden sled that the auctioneer claimed was made by none other than George Washington himself.

The auctioneer turned the sled over and read the following inscription carved into one of the wooden slats:
G. Washington, September 10, 1752.

However, someone in the crowd stood up and said it's a fake. How did that person know?


Solution:

Under the Julian calendar, leap year occurred every four years, making the average length of a year 365.25 days. That average length was too long, so that by the middle of the sixteenth century, the error had accumulated to more than 10 days.

Pope Gregory XIII decreed a correction to this error in 1582, and Britain, which included the present-day United States and Canada, made this change in 1752.

Wednesday, September 2, 1752, Julian was followed by Thursday, September 14, 1752, Gregorian in all countries of the British Empire.

So there was no September 10, 1752 in the United States!

The calendar used today in the United States is called the Gregorian Calendar Reform of 1582/1752. It adds a day every four years (those years are called leap years). There is an exception to the rule. When the year is evenly divisible by 100, it is not a leap year; but when it is divisible by 400, it is a leap year. So 1900 was not a leap year but the year 2000 is!

George Washington was born on February 11, 1732, by the Julian calendar which was then in use. In 1752, when the Gregorian calendar was adopted and 11 days were dropped, Washington shifted his birth date in order to keep the "real" day. That's why we now celebrate his birthday on the 22nd.

My apologies for this "history" problem, but I thought it was appropriate with all the talk about Y2K and other calendar related events like when the millennium starts. We will stick to math and logic puzzles from now on!



Correctly solved by:

1. Tom Marino Winchester, VA

Some good ideas were sent in by:

2. Elizabeth Cotter Oak Hill, VA
3. Jia Ran Rome, Italy