<Tr> <Td> </Td> <Td> ​ 1 ⁄ </Td> <Td> </Td> <Td> </Td> <Td> 6 </Td> <Td> tierces </Td> </Tr> <Tr> <Td> </Td> <Td> ​ 1 ⁄ </Td> <Td> </Td> <Td> ​ 2 ⁄ </Td> <Td> </Td> <Td> 8 </Td> <Td> barrels </Td> </Tr> <Tr> <Td> </Td> <Td> ​ 1 ⁄ </Td> <Td> ​ 2 ⁄ </Td> <Td> ​ 3 ⁄ </Td> <Td> ​ 4 ⁄ </Td> <Td> 7 </Td> <Td> 14 </Td> <Td> rundlets </Td> </Tr> <Tr> <Td> </Td> <Td> 18 </Td> <Td> ​ 31 ⁄ </Td> <Td> 42 </Td> <Td> 63 </Td> <Td> 84 </Td> <Td> 126 </Td> <Td> 252 </Td> <Td> gallons (wine) </Td> </Tr>

How many gallons are in a whiskey barrel