John Wheeler: Traditionally, barometers measured air pressure in inches Today, the metric units of the bar and the millibar are the preferred units of scientists.

Gimbal-mounted mercury barometer with a rosewood case. The ivory scale extends from 26.5 to 31 inches of mercury, is read by vernier to 0.01 inch, and indicates “STORMY,” “RAIN,” “CHANGE,” and “FAIR.” ...

Nicolas Fortin, an instrument maker in Paris in the early nineteenth century, introduced a mercury barometer with a glass and leather cistern so designed that the barometer could be safely moved from ...