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The population history of China covers the long-term pattern of population growth in China and its impact on the history of China. The population went through many cycles that generally reached peaks along each imperial power and was decimated due to wars and barbarian invasions. The census data shows that the population as percentage share of ...
China is the second most populous country in Asia as well as the second most populous country in the world, with a population of approximately 1.4 billion. China has an enormous population with a relatively small youth component, partially a result of China's one-child policy that was implemented from 1979 until 2015.
Published estimates for the 1st century ("AD 1") suggest uncertainty of the order of 50% (estimates range between 150 and 330 million). Some estimates extend their timeline into deep prehistory, to " 10,000 BC", i.e., the early Holocene, when world population estimates range roughly between 1 and 10 million (with an uncertainty of up to an ...
1676 - Daniel Quare, a London clock-maker, invents the repeating clock, that chimes the number of hours (or even minutes). [7] 1680 - Second hand introduced. 1737 - John Harrison presents the first stable marine chronometer, thereby allowing for precise longitude determination while at sea. 1850 - Aaron Lufkin Dennison starts in Roxbury, Mass.U ...
The history of Alaska dates back to the Upper Paleolithic period (around 14,000 BC ), when foraging groups crossed the Bering land bridge into what is now western Alaska. At the time of European contact by the Russian explorers, the area was populated by Alaska Native groups. The name "Alaska" derives from the Aleut word Alaxsxaq (also spelled ...
The Shortt–Synchronome clock, an electrical driven pendulum clock designed in 1921, was the first clock to be a more accurate timekeeper than the Earth itself. [167] A succession of innovations and discoveries led to the invention of the modern quartz timer. The vacuum tube oscillator was invented in 1912. [168]
The first gēng theoretically comes at sundown, but was standardized to fall at yǒu shí central 1 kè, or 19:12. The time between each gēng is 1⁄10 of a day, making a gēng 2.4 hours—or 2 hours 24 minutes—long. The 5 gēngs in the night are numbered from one to five: yì gēng ( 一 更) (alternately chū gēng ( 初更) for "initial ...
Time clock. A time clock, sometimes known as a clock card machine, punch clock, or time recorder, is a device that records start and end times for hourly employees (or those on flexi-time) at a place of business. In mechanical time clocks, this was accomplished by inserting a heavy paper card, called a time card, into a slot on the time clock.