Opera hat described as: Some sources have taken this to describe an early folding top hat, although it is not explicitly stated whether Dollman's design was specifically for male or female headgear. Dollman's patent expired in 1825. Operating from Poissy, Paris, France, around 1840, Antoine Gibus's design for a spring-loaded collapsible top-hat proved so popular that hats made to it became known as "gibus". They were also often called "opera hats" due to the common practice of storing them in their flattened state under one's seat at the opera, though the term can also refer to any tall formal men's hat. The
Top hat popularity of the silk plush top hat possibly led to a decline in beaver hats, sharply reducing the size of the beaver trapping industry in North America, though it is also postulated that the beaver numbers were also reducing at the same time. Whether it directly affected or was coincidental to the decline of the beaver trade is debatable. James Laver once observed that an assemblage of "toppers" resembled factory chimneys and thus added to the mood of the industrial era. In England, post-Brummel dandies went in for flared crowns and swooping brims. Their counterparts in France, known as the