LiveWire

“…When he was not writing literary works like Alice's Adventures in Wonderland, Lewis Carroll dabbled in mathematics. One of the results of his diversion was an 1887 perpetual calendar algorithm for calculating the day of the week for a given date. Many calendar algorithms preceded Carroll's… Carroll was the first person to devise an algorithm suitable for mental calculation… John Horton Conway,…a world-class mathematician, did come up with a much simpler algorithm in 1973. He called his algorithm the “doomsday rule.” … The Gregorian calendar was not widely adopted across the world until much later. In fact, the British Empire and its colonies did not use the updated calendar system until 1752. By then the Julian calendar was out of sync with the seasons by 11 days. In order to synchronize with the Gregorian calendar, it was mandated that Wednesday, September 2, 1752, be followed by Thursday, September 14, 1752. Hence, the date September 6, 1752, does not exist in British and American history!…”