Henry Ernest Dudeney/Modern Puzzles/219 - A Calendar Puzzle

by : $219$

 * A Calendar Puzzle
 * I have stated in my book,, that, under our present calendar rules,
 * the first day of a century cannot fall on a Sunday or a Wednesday or a Friday.
 * I am frequently asked the reason why.
 * Try to explain the mystery in as simple a way as possible.


 * Note that $1$st January $1901$ was the first day of the $20$th century, not $1900$.