| 摘要 |
A tablet that is suitable for use underwater or in any extreme environment is provided. The tablet is designed, through the use of buoyant materials such as polystyrene, to have a slightly negative buoyancy at a depth of about fifty feet so that it can be very easy to manipulate underwater and will not sink or ascend rapidly if let go. A length of waterproof (plastic) vellum is stretched between two rollers to form a drawing or writing surface thereby enabling the user to easily record information on the vellum.
|
