answersLogoWhite

0

Technically, millimeters of Mercury. These days, though, inches of Mercury is much more common. When the weatherman says that the barometer is 29.7, they are referring to the number of inches that the air pressure will force mercury to go up inside a glass tube. These days, they don't use the actual mercury column so much, but rather mechanical barometers.

User Avatar

Wiki User

12y ago

What else can I help you with?