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 "ale gallon" known as the "imperial gallon" and abolished all other gallons in favour of it. Inspired by the kilogram-litre relationship, the imperial gallon was based on the volume of 10 pounds of distilled water weighed in air with brass weights with the barometer standing at 30 inches of mercury and at a temperature of . In 1963, this definition was refined as the space occupied by 10 pounds of distilled water of density weighed in air of density against weights of density (the original "brass" was refined as the density of brass alloys vary depending on metallurgical composition). This