![]() Caoutchouc was named rubber in 1770 by the English chemist Joseph Priestley, because it was used to rub out marks. In 1752 the Proceedings of the French Academy of Sciences reported a suggestion for using caoutchouc, a vegetable gum produced by certain South American trees, to erase black lead marks. The mixture is processed and extruded and, if made with rubber, vulcanized to bond the ingredients. The modern eraser is usually a mixture of an abrasive such as fine pumice, a rubbery matrix such as synthetic rubber or vinyl, and other ingredients. SpaceNext50 Britannica presents SpaceNext50, From the race to the Moon to space stewardship, we explore a wide range of subjects that feed our curiosity about space!Įraser, piece of rubber or other material used to rub out marks made by ink, pencil, or chalk.Learn about the major environmental problems facing our planet and what can be done about them! ![]() Saving Earth Britannica Presents Earth’s To-Do List for the 21st Century.100 Women Britannica celebrates the centennial of the Nineteenth Amendment, highlighting suffragists and history-making politicians.COVID-19 Portal While this global health crisis continues to evolve, it can be useful to look to past pandemics to better understand how to respond today. ![]()
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |