Gallon - History

History

The term derives most immediately from galun, galon in Old Northern French, but the usage was common in several languages, for example jale in Old French and gęllet (bowl) in Old English. This implies a common origin in Romance Latin, but the ultimate source of the word is unknown. The gallon originated as the base of systems for measuring wine, and beer in England. The sizes of gallon used in these two systems were different from each other: the first was based on the wine gallon (equal in size to the US gallon), and the second on either the ale gallon or the smaller imperial gallon.

By the end of the 18th century, three definitions of the gallon were in common use:

• The corn gallon, or Winchester gallon, of about 268.8 cubic inches (≈ 4.405 L),
• The wine gallon, or Queen Anne's gallon, which was 231 cubic inches (≈ 3.79 L), and
• The ale gallon of 282 cubic inches (≈ 4.62 L).

The corn or dry gallon was used in the United States until recently for grain and other dry commodities. It is one-eighth of the (Winchester) bushel, originally a cylindrical measure of 18 1⁄₂ inches in diameter and 8 inches in depth. That made the dry gallon (9 1⁄₄)2 × π cubic inches ≈ 268.80252 cu in. The bushel, which like dry quart and pint still sees some use, was later defined to be 2150.42 cubic inches exactly, making its gallon exactly 268.8025 cu in (4.40488377086 L). In previous centuries, there had been a corn gallon of around 271 to 272 cubic inches.

The wine, fluid, or liquid gallon has been the standard US gallon since the early 19th century. The wine gallon, which some sources relate to the volume occupied by eight medieval merchant pounds of wine, was at one time defined as the volume of a cylinder six inches deep and seven inches in diameter, i.e. 6 in × (3 1⁄₂ in)2 × π ≈ 230.907 06 cubic inches. It had been redefined during the reign of Queen Anne, in 1706, as 231 cubic inches exactly (3 in × 7 in × 11 in), which is the result of the earlier definition with π approximated to 22⁄₇. 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 (224 cu in) was actually in use, so this statute became necessary. It remains the US definition today.

In 1824, Britain adopted a close approximation to the 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 62 °F. In 1963, this definition was refined as the space occupied by 10 pounds of distilled water of density 0.998859 g/mL weighed in air of density 0.001217 g/mL against weights of density 8.136 g/mL. This works out at approximately 4.5460903 L (277.41945 cu in). The metric definition of exactly 4.54609 cubic decimetres (also 4.54609 L after the litre was redefined in 1964, ≈ 277.419433 cu in) was adopted shortly afterwards in Canada, but from 1976 the conventional value of 4.546092 L was used in the United Kingdom until the Canadian convention was adopted in 1985.