The internet wasn't needed for news to travel, there were ships and people traveling back and forth all the time. Guys like Franklin practically commuted, as well as corresponding with smart guys all over Europe. News of longer, lower, wider, ways to improve productivity traveled fast. We'd had water powered mills here for 150 years or more by 1800, and before 1776 a lot of mills here were owned by foreigners. Even if a couple of those foreigners had round blades who's to say a woman didn't think of it. But nobody patented it, so Tabitha wins because she was obviously a witch, being Samantha's kid.
