That’s the playground rhyme that everyone learns when they are young. Many a misplaced quarter or toy has been claimed under that rule, which by according to some sources dates back to Roman property law. Although, I doubt that this little couplet adequately summarizes the entire view of ancient attorneys on the subject.
But still, it serves for most folks as a standard we apply when we encounter a lost dime, dollar, or other object with no discernible owner and of modest value. It’s not a hard and fast standard, of course.