Definition
A unit of dry measure historically used in English and early American law, most commonly applied to coal and coke. As defined in legal usage, the chaldron equaled approximately 58⅔ cubic feet. The measure was not uniform across localities, which is the central difficulty researchers encounter when working with period documents that reference it.
Common Language
Modern common usage (Wiktionary): Listed as an alternative form of "chawdron," a word of uncertain application, with no meaningful modern usage as a unit of measure.
Historical common usage (Webster's 1913): An English dry measure equal to 36 heaped bushels (or equivalent weight) at London, but considerably larger at Newcastle, where it exceeded twice the London standard. By 1913, used exclusively for coal and coke.
The legal significance of the chaldron is not in its definition but in its instability. Bouvier's figure of approximately 58⅔ cubic feet and Webster's reference to 36 heaped bushels cannot be straightforwardly reconciled without knowing which locality's standard was in use. A researcher encountering the term in a contract, tariff schedule, or shipping record must treat the measure as jurisdiction- and trade-specific, not as a fixed quantity.
Why It Matters in Research
The chaldron appears most frequently in commercial and admiralty documents — coal trade contracts, customs records, port tariffs, and cargo disputes — from roughly the seventeenth through nineteenth centuries. Its presence in American legal materials reflects the inherited English coal trade vocabulary that persisted in Atlantic port commerce well into the 1800s.
The critical trap is assuming a single value. The London chaldron and the Newcastle chaldron were different measures, and American usage sometimes borrowed one standard, sometimes the other, and occasionally used neither consistently. When a document assigns a price, tax, or obligation per chaldron, the actual quantity at stake cannot be determined from the word alone. Researchers must look to surrounding context — the port of origin, the counterparties, the trade route — to anchor the figure.
Bouvier's citation to Cowel (John Cowell's legal dictionary, The Interpreter, first published 1607) signals that the chaldron was already a term requiring definition in early modern legal practice, not a self-evident measure. That chain of citation — Cowell to Bouvier — reflects the term's persistence in legal reference literature long after it had faded from everyday commerce.
For researchers working in coal-related regulatory history, the chaldron also appears in early English statutes governing the coal trade, where Parliament periodically attempted to standardize the measure. American statutes and municipal ordinances occasionally referenced the chaldron when regulating coal sales by weight versus volume, a tension that ran through the nineteenth century as weight-based standards gradually displaced volume measures.
Historical Dictionary Support
Bouvier's is spare on this term, offering only the cubic-foot figure and a single citation to Cowell. That brevity is itself informative: by the time of Bouvier's major editions, the chaldron was already a historical curiosity in American legal practice rather than a live term of art requiring extended analysis. Bouvier preserves it as a reference point for reading older documents, not as a term with ongoing legal vitality.
Webster's 1913 adds practical texture that Bouvier omits — specifically, the London/Newcastle divergence — and confirms that by the early twentieth century the term had retreated entirely to the coal and coke trades. Neither source addresses the American variant usage or the tension between volume and weight measurement that complicated the term's application in commercial disputes.
No other dictionary on the Law Mind shelf treats this term. Researchers needing deeper historical grounding should consult Cowell's The Interpreter directly and period commodity trade records.
Jurisdictional Note
The measure was English in origin and carried different values in different English localities. American legal use was derivative and inconsistent. Any document referencing the chaldron in a colonial or early federal American context should be treated as potentially adopting an English local standard that may not match Bouvier's figure.