law of diminishing returns. A concept in economics that if one factor of production (number of workers, for example) is increased while other factors (machines and workspace, for example) are held constant, the output per unit of the variable factor will eventually diminish.
History of glass. The history of glassmaking can be traced back to 3500 BCE in Mesopotamia, but Mesopotamians may have created second-rate copies of glass objects from Egypt, where this complex craft actually originated. Other archaeological evidence suggests that the first true glass was made in coastal north Syria, Mesopotamia or Egypt.
Augmented by the action of the vacuum, which initiated the second stage of the brewing process, the result was an elegantly simple system which produced an excellent cup of coffee. The earliest glass vacuum pots appear to have been in use in Germany by the 1830âs, as witnessed by a patent filed in France by Mme. Jeanne Richard in 1838. This patent shows a design which which referenced an existing vacuum pot by Loeff of Berlin.