Paper size a number of different sizes were defined for large sheets of paper, and paper sizes were defined by the sheet name and the number of times it had been folded. Thus a full sheet of "royal" paper was 25 × 20 inches, and "royal octavo" was this size folded three times, so as to make eight sheets, and was thus 10 × inches. Imperial sizes were used in the United Kingdom and its territories. These sizes are no longer commonly used since the UK switched to ISO sizes. Many of these sizes were only used for making books (see bookbinding),
Sheet erosion Sheet erosion Sheet erosion or sheet wash is the even erosion of substrate along a wide area. Sheet erosion occur in wide range of settings such as coastal plains, hillslopes, floodplains and beaches. Water moving fairly uniformly with a similar thickness over a surface is called sheet flow and is the cause of sheet erosion. Sheet erosion imply that any flow of water that causes the erosion is not canalized. If a hillsplope surface contains many irregularities sheet erosion may give way to erosion along small channels called rills which can converge forming gullies. However, sheet erosion may occur despite