Mercurial Barometer

Science / Weather / Mercurial Barometer: An instrument used for measuring the change in atmospheric pressure. It uses a long glass tube, open at one end and closed at the other. After first filling the open end with mercury, it is then temporarily sealed and placed into a cistern of mercury. A nearly perfect vacuum is established at the closed end after the mercury descends. The height of the column of mercury in the tube is a measurement of air pressure. As atmospheric pressure increases, the mercury is forced from the cistern up the tube; when the atmospheric pressure decreases, the mercury flows back into the cistern. Measurement is taken in inches of mercury. Although mercurial barometers are very accurate, practicality has led observers to use aneroid barometers. First used by Evangelista Torricelli (1608-1647), an Italian physicist and mathematician, to explain the fundamental principles of hydromechanics.

Barometer

Science / Chemistry / Barometer: An instrument that measures atmospheric pressure. A mercury barometer is a closed tube filled with mercury inverted in a mercury reservoir. The height of the mercury column indicates atmospheric press MORE

Mercurial Barometer

Science / Weather / Mercurial Barometer: An instrument used for measuring the change in atmospheric pressure. It uses a long glass tube, open at one end and closed at the other. After first filling the open end with mercury, it is then tempo MORE

January Barometer

Business / Finance / January Barometer: A statistic from 'The Stock Traders Alamanac' reflecting, with 88% accuracy, that the overall stock market rises in a year when the S&P is up in the month of January and drops when the index for that MORE

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