Which type of barometer does not use liquid for pressure measurement?

The aneroid barometer is a device that measures atmospheric pressure without the use of any liquid. Instead, it uses a small, flexible metal box called an aneroid cell, which expands and contracts with changes in atmospheric pressure. This movement is then converted into a reading on a dial.

This type of barometer is beneficial because it is more portable and durable than liquid-based barometers, like the mercury barometer, which can be fragile and hazardous due to the toxic nature of mercury. Aneroid barometers are often used in various applications, including altimeters in aviation, because they can give rapid measurements and are less affected by the liquid's properties.

By contrast, mercury and electronic barometers typically either contain liquid or rely on electronic sensors and displays that represent pressure changes indirectly. Manometers also rely on liquid to measure pressure differences between two points. Therefore, the aneroid barometer stands out as the only option that operates without any liquid.