††††Thermos is the registered trade name for a type of vacuum flask, a container for keeping liquids either hot or cold.
In 1892, James Dewar found a way of maintaining gases and liquids at a constant temperature. He developed a glass vessel with double walls separated by a vacuum. His first prototype was called a"Dewar Vessel". He developed a 'silver' inner surface on the glass by using a minute quantity of mercury as a gas. The design of the vessel reduced the three forms of heat transfer: radiation (prevented by the silvering) and conduction and convection (both prevented by the vacuum). The first manufacture of Vacuum Flasks took place in Germany in 1904.
