<Table> <Tr> <Td> </Td> <Td> This article needs additional citations for verification . Please help improve this article by adding citations to reliable sources . Unsourced material may be challenged and removed . (May 2016) (Learn how and when to remove this template message) </Td> </Tr> </Table> <Tr> <Td> </Td> <Td> This article needs additional citations for verification . Please help improve this article by adding citations to reliable sources . Unsourced material may be challenged and removed . (May 2016) (Learn how and when to remove this template message) </Td> </Tr> <P> Inch of mercury (inHg and "Hg) is a unit of measurement for pressure . It is still used for barometric pressure in weather reports, refrigeration and aviation in the United States . </P> <P> It is the pressure exerted by a column of mercury of 1 inch (25.4 mm) in height at the standard acceleration of gravity . Conversion to metric units depends on the temperature of mercury, and hence its density; typical conversion factors are: </P>

What does hg stand for in metric system