<Tr> <Td> 1 pound (lb) </Td> <Td> 16 oz </Td> <Td> 6999453592370000000 ♠ 453.592 37 g </Td> </Tr> <Tr> <Td> 1 US hundredweight (cwt) </Td> <Td> 100 lb </Td> <Td> 7001453592370000000 ♠ 45.359 237 kg </Td> </Tr> <Tr> <Td> 1 long hundredweight </Td> <Td> 112 lb </Td> <Td> 7001508023454400000 ♠ 50.802 345 44 kg </Td> </Tr> <Tr> <Td> 1 ton (short ton) </Td> <Td> 20 US cwt or 2000 lb </Td> <Td> 7002907184740000000 ♠ 907.184 74 kg </Td> </Tr>

When was the us system of measurement invented