- Cuneiform
Sumerians originate wedge-shaped writing.
About 5,000 years ago, the Sumerians of ancient Mesopotamia invented human-kind's first writing system. Having already established the World's first true civiliza-tion by introducing agriculture and domesticating cattle, they decided that it was more efficient to record their lives economic transactions in writing rather than use tokens to represent the number of beasts and the amount of harvest they
traded. Their initial use of simple pictograms (drawings representing actual things) quickly developed into a complex system of symbols where items were illustrated by one sign and their volume by another.
The Sumerians innovation was not only used for commercial purposes, but also extended to phonetic rather than wholly pictographic-Ideograms that expressed concepts such as deity and l royalty as well as thoughts.
As the symbols evolved, the notes that were recorded on clay tablets became more cuneiform (wedge-shaped), owing to the wedge-tipped reed the Sumerians used as a writing utensil. They were initially drawn in vertical columns, but the writing direction soon changed to left to right in horizontal rows. Rediscovered in the nineteenth century, the cuneiform script (whose last known inscription is an astronomical text from 75 C.E.) Carries major significance as the first means of chronicling events in writing.
SEE ALSO: ALPHABET, INK, ABACUS, PARCHMENT, QUILL PEN, WOODBLOCK PRINTING, HINDU-ARABIC NUMERALS
- Dam
Egyptians block a river for the first time.
Dams are built for a number of purposes: to generate hydroelectric power; control flooding; safeguard water supplies for irrigation, domestic, or industrial use; provide for recreation; or ease navigation.
The earliest known dam was built by the Egyptians across the Garawi Valley in 2800 B.C.E. and measured 370 feet (113 m) along its crest. The masonry shell was filled with earth and rubble, but as it was not sealed against water, the center of the dam was soon washed away. This failure discouraged the Egyptians from further forays into dam construction.
The Romans, armed with their knowledge of concrete, were more successful . Their constructions initially relied on sheer weight of material to resist the water, but in the first century they built the first arch-type dam at Glanum in France. The apex of the arch pointed upstream, transferring the force along the dam and into the solid bedrock of the valley sides. This design was also favored by the Mongols in fourteenth-century Iran, but it was otherwise little used until the nineteenth century, when French engineer François Zola designed his eponymous arch dam, using rational stress analysis for the first time.
In the latter half of the nineteenth century, concrete was used as the primary construction material tor the first time in a gravity dam in New York and an arch dam in Queensland, Australia. More complex structures were now within reach, and multiple arch, cupola, and buttress dams sprang up around the United States.
China is home to the world's largest dam project, the Three Gorges Dam, which is expected to be fully operational in 2009. It spans the Yangtze River and has been constructed to ease flooding on the Yangtze and provide hydroelectric power for millions.
SEE ALSO: IRRIGATION, CANAL, ENCL-OSED HARBOR