Top hat ribs and springs. His patent was 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. In 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
Top Hat (company) they witnessed while studying at the University of Waterloo. Early on, the company’s sales approach involved selling directly to academic administration "who had little incentive or interest in changing the way students access course materials," according to Silagadze. The firm changed its tactics to sell directly to educators, a strategy that,according to the company, has resulted in more than two million student subscribers across North America and beyond. The company claims that they are used in over 1000 universities. , Top Hat charges no platform fees for students when their professors assign Open Educational Resources. In 2017, Top Hat was