The US has never used the Imperial system. The Imperial system was established by the British Weights and Measures Act of 1824, after the US gained independence. The US uses "US Customary Units", which take their names from the British units in use in 1776. There are, however, a few significant differences between US and Imperial units, particularly liquid measures (an Imperial gallon is about 1.2 US gallons). The US attempted to standardize the US yard and pound with the 1855 Imperial standards (the originals were lost in a fire in 1834). In 1893, Thomas Corwin Mendenhall, then superintendent of the U.S. Coast and Geodetic Survey, redefined the US units in terms of the metric system. The US and Imperial weight and length units were not reconciled until 1959, with the International Yard and Pound agreement.