Why has mercury traditionally been used in liquid-column barometers?

A. It is the best liquid for every instrument

B. Its high density keeps the column relatively short

C. Its vapor pressure is very low

D. Both B and C

E. It moves more easily than every other liquid

Explanation

Mercury's high density allows atmospheric pressure to be balanced by a column about 760 mm high at sea level, while its very low vapor pressure makes the pressure above the column negligible for ordinary measurements.

Source

WMO Guide to Instruments and Methods of Observation

Answer verified on 2026-09-12

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