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.
The earliest glass tile mosaics were made during this period from thin slices of colored glass rods inlaid upon walls, wooden boxes and ceramic vessels. The Roman Empire The Syrians invented the blowpipe around 300 BC and the foundation of modern glassblowing was laid. The Roman Empire embraced these new techniques for making glass vessels and experimentation with a wide variety of new shapes and forms began.