Watching Copper, you’d think that New York in the 1860s was all about brass-knuckle brawls in bordellos, opium-fueled sex romps, and chasing criminals with names like Buzzy Burke through seedy Five Points. But there was a lighter side—in an era where finding the next cat with eyebrows wasn’t so easy, P.T. Barnum was the public’s point of entry to the world of the bizarre and extraordinary. Yes, the same man behind the famous circus…