Well, then, wasn't the character Sherlock Holmes based on a lecturer at Edinburgh U, named Dr. Joseph Bell? I think this is a picture of Bell. Sherlock should have one of these hats, with the snap in front. Can't find the name of that kind of hat. Looks a little worn out in this picture.
The hat Napoleon is said to have worn at the Battle of Waterloo sells for more than $400K "The hat, which was sold 203 years to the day after the French emperor's defeat at the famous battle, is believed to be one of about 120 two-cornered military dress hats worn by Napoleon. Historians have identified only 19 remaining hats, most of them now in museums. According to the auction house, Napoleon constantly had 12 hats in service, each of which had a three-year life span." The hat sold Monday is believed to have been picked up after the Battle of Waterloo and the flight of Napoleon by a Dutch captain, Baron Arnout Jacques van Zuijlen van Nijevelt.