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An eraser, (also called a rubber in Canada,〔http://dictionary.canadaspace.com/definition/rubber/〕 the UK, Ireland, India, Australia, New Zealand, and South Africa, from the material first used) is an article of stationery that is used for removing writing from paper. Erasers have a rubbery consistency and come in a variety of shapes, sizes and colours. Some pencils have an eraser on one end. Less expensive erasers are made from synthetic rubber, but more expensive or specialized erasers are vinyl, plastic, or gum-like materials. Cheaper erasers can be made out of synthetic soy-based gum. Erasers were initially made for pencil markings, but more abrasive ink erasers were later introduced. The term is also used for things that remove writing from chalkboards and whiteboards. ==History== Before rubber erasers, tablets of rubber or wax were used to erase lead or charcoal marks from paper. Bits of rough stone such as sandstone or pumice were used to remove small errors from parchment or papyrus documents written in ink. Crustless bread was used as an eraser in the past; a Meiji-era (1868-1912) Tokyo student said: "Bread erasers were used in place of rubber erasers, and so they would give them to us with no restriction on amount. So we thought nothing of taking these and eating a firm part to at least slightly satisfy our hunger." In 1770 English engineer Edward Nairne is reported to have developed the first widely-marketed rubber eraser, for an inventions competition. Until that time the material was known as ''gum elastic'' or by its native American name (via French) ''caoutchouc''. Nairne sold natural rubber erasers for the high price of three shillings per half-inch cube. According to Nairne, he inadvertently picked up a piece of rubber instead of breadcrumbs, discovered rubber's erasing properties, and began selling rubber erasers. The invention was described by Joseph Priestley on April 15, 1770, in a footnote: "I have seen a substance excellently adapted to the purpose of wiping from paper the mark of black-lead-pencil. ... It is sold by Mr. Nairne, Mathematical Instrument-Maker, opposite the Royal-Exchange."〔See the footnote on page xv at the end of the preface to the following: 〕 In 1770 the word ''rubber'' was in general use for any object used for rubbing; the word became attached to the new material sometime between 1770 and 1778.〔R.B. Simpson (ed.), ''Rubber Basics'', iSmithers Rapra Publishing, 2002, ISBN 185957307X, p.46 "Rubber"〕 However, raw rubber was perishable. In 1839 Charles Goodyear discovered the process of vulcanization, a method that would cure rubber, making it durable. Rubber erasers became common with the advent of vulcanization. On March 30, 1858, Hymen Lipman of Philadelphia, USA, received the first patent for attaching an eraser to the end of a pencil. It was later invalidated because it was determined to be simply a composite of two devices rather than an entirely new product.〔(【引用サイトリンク】title=Reckendorfer v. Faber 92 U.S. 347 (1875) )〕 Erasers may be free-standing blocks (''block'' and ''wedge eraser''), or conical caps that can slip onto the end of a pencil (''cap eraser''). A ''barrel'' or ''click eraser'' is a device shaped like a pencil, but instead of being filled with pencil lead, its barrel contains a retractable cylinder of eraser material (most commonly soft vinyl). Many, but not all, wooden pencils are made with attached erasers. Novelty erasers made in shapes intended to be amusing are often made of hard vinyl, which tends to smear heavy markings when used as an eraser. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「eraser」の詳細全文を読む スポンサード リンク
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