Dry gallon measure of approximately the same size, though the dry gallon is a bit bigger. 1 dry gallon ≈ 1.163 647 fluid gallons Its implicit value in the US system was originally one eighth of the Winchester bushel, which was a cylindrical measure of 18.5 inches in diameter and 8 inches in depth. That made the dry gallon a non-terminating number of cubic inches, an irrational number whose value with the first six digits after the decimal point was 268.802521 ( cubic inches ≈ ). The bushel was later defined to be exactly 2150.42 cubic inches, making the dry gallon exactly
Gallon one time defined as the volume of a cylinder 6 inches deep and 7 inches in diameter, i.e. . It had been redefined during the reign of Queen Anne, in 1706, as 231 cubic inches exactly, which is the result of the earlier definition with π approximated to . Although the wine gallon had been used for centuries for import duty purposes there was no legal standard of it in the Exchequer and a smaller gallon was actually in use, so this statute became necessary. It remains the US definition today. In 1824, Britain adopted a close approximation to the