Definition
A unit of liquid measure equal to 231 cubic inches, or four liquid quarts. In American commercial and legal usage, this is the wine gallon standard, which has served as the baseline for statutory weights and measures since the early republic. Two historical variants appear in legal sources: the imperial gallon (approximately 277 cubic inches), used in British law, and the ale gallon (approximately 282 cubic inches), a now-obsolete measure once applied to beer and ale commerce.
Common Language
Modern common usage (Wiktionary): A measure of capacity containing four quarts; used in liquid measure and sometimes dry measure.
Historical common usage (Webster's 1913): A measure of capacity containing four quarts; used for the most part in liquid measure, but sometimes in dry measure.
Editorial note: The common and legal meanings are largely aligned, but the law draws a sharper distinction than everyday usage does. Ordinary speech treats "gallon" as a single self-evident unit, while legal and commercial contexts historically required precision about which gallon standard applied — wine, ale, or imperial. That distinction carried real consequences in customs, tax, and trade disputes, particularly in cases involving imported goods subject to duties calculated by liquid volume.
Common Confusion
The wine gallon (231 cubic inches), the ale gallon (approximately 282 cubic inches), and the imperial gallon (approximately 277 cubic inches) are three distinct legal standards that share the same name. Researchers working in British-influenced colonial sources or early American customs records must be alert to which standard a document invokes. The ale gallon fell out of American statutory use early; the imperial gallon remains the standard in the United Kingdom, Canada, and other Commonwealth jurisdictions. Uncritical reading of historical statutes or tariff schedules that simply say "gallon" can produce significant measurement errors.
Why It Matters in Research
The gallon's legal significance is almost entirely confined to two domains: weights and measures statutes and customs or revenue law. Researchers will encounter the term most often in early American statutory compilations, federal tariff and revenue cases, and state commercial regulation.
The key navigational point is the wine-gallon-as-default rule in American law. The 231-cubic-inch standard was adopted by Congress and replicated in state statutory schemes, with New York's early Revised Statutes being a frequently cited example (noted by Burrill). When a federal customs case turns on the dutiable quantity of an imported liquid, the wine gallon standard governs American law — a point litigated in federal circuit court decisions cited in Black's 2nd edition.
For researchers in the Law Mind corpus, watch for three traps: (1) British legal materials using "gallon" mean the imperial gallon, not the American wine gallon — a difference of roughly 20 percent by volume; (2) pre-standardization colonial and early state sources may reference the ale gallon in the context of brewing or tavern regulation; (3) dry measure occasionally used "gallon" as a unit in older agricultural and grain trade records, though this usage is rare in legal instruments and had effectively disappeared from American statutory drafting by the mid-nineteenth century.
Customs and revenue cases involving the gallon often arise in the context of spirits, wine, oil, and molasses — commodities where small per-unit differences in measured volume aggregated into significant duty calculations.
Historical Dictionary Support
The historical dictionaries are in close agreement on substance. Black's (both editions), Bouvier's, and Anderson's all define the gallon as 231 cubic inches or four quarts and note the imperial (277 cubic inches) and ale (282 cubic inches) variants. The definitions are brief and functional — these sources treat the term as a technical measurement standard requiring accurate statement, not legal analysis.
Burrill adds the most jurisdictionally useful detail, anchoring the definition to New York's Revised Statutes and identifying the gallon as the statutory unit from which other measures of capacity were derived. This reflects a common nineteenth-century legislative pattern: states chose a baseline unit and expressed all other volumetric measures as multiples or fractions of it.
What the historical dictionaries collectively omit is any sustained treatment of how courts actually applied the wine/ale/imperial distinction in litigation. That analytical work appears in the case law rather than the dictionaries.
Jurisdictional Note
The United States uses the wine gallon standard (231 cubic inches); the United Kingdom, Canada, Australia, and other Commonwealth jurisdictions use the imperial gallon (approximately 277.4 cubic inches). This divergence is significant in any cross-border trade, tariff, or commercial dispute where quantity is calculated by gallon. Researchers should not assume interchangeability when working with documents that span both legal systems.