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The word gypsum is derived from the Greek word γύψος (gypsos), "plaster". [9] Because the quarries of the Montmartre district of Paris have long furnished burnt gypsum (calcined gypsum) used for various purposes, this dehydrated gypsum became known as plaster of Paris. Upon adding water, after a few dozen minutes, plaster of Paris becomes ...
While working in Haarlem at the military hospital in 1851, Mathijsen first used plaster of Paris as a bandage. [1] Until then a Belgian method was used with starch that took up to a day to dry and harden. [1] Across the street he watched workers repairing cracks in the church with strips of jute dunked in plaster of Paris.
Plaster bandages are used to construct an impression of a patient's head and neck, and liquid plaster is used to fill the impression and produce a plaster bust. The transparent material polymethyl methacrylate (Plexiglas, Perspex) is then vacuum formed over this bust to create a clear face mask which will hold the patient's head steady while ...
In the form of γ-anhydrite (the anhydrous form), it is used as a desiccant. One particular hydrate is better known as plaster of Paris, and another occurs naturally as the mineral gypsum. It has many uses in industry. All forms are white solids that are poorly soluble in water. [5] Calcium sulfate causes permanent hardness in water.
Around 19 school boards from 14 states have adopted or adapted the books. [11] Those who wish to adopt the textbooks are required to send a request to NCERT, upon which soft copies of the books are received. The material is press-ready and may be printed by paying a 5% royalty, and by acknowledging NCERT. [11]
The use of scagliola declined in the 20th century. [3] Scagliola is a composite substance made from plaster of Paris, glue and natural pigments, imitating marble and other hard stones. The material may be veined with colors and applied to a core, or desired pattern may be carved into a previously prepared scagliola matrix.
The modern use of this material may be said to have started then, but the use of fibrous plaster was known and practiced by the Egyptians long before the Christian era; for ancient coffins and mummies still preserved prove that linen stiffened with plaster was used for decorating coffins and making masks.
The end of the Roman Empire in the west, and the creation of the Merovingian dynasty in the 5th century, with its capital placed in Paris by Clovis I, confirmed the new role and name for the city. The adjective Parisiacus had already been used for centuries. Lutetia had gradually become Paris, the city of the Parisii. [22]