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Chaldron wagon at Beamish.
Note the long brake lever for control when running down to the staith by gravity.

A chaldron (also chauldron or chalder) was an English measure of dry volume, mostly used for coal; the word itself is an obsolete spelling of cauldron. It was used from the 13th century onwards, nominally until 1963 when it was abolished by the Weights and Measures Act 1963 but in practice until the end of 1835 when the Weights and Measures Act of that year specified that thenceforth coal could only be sold by weight.


The chaldron was used as the measure for coal from the 13th century, measuring by volume being much more practical than weighing low-value, high-bulk commodities like coal. It was not standardized, and there were many different regional chaldrons, the two most important being the Newcastle and London chaldrons. The Newcastle chaldron was used to measure all coal shipped from Northumberland and Durham, and the London chaldron became the standard measure for coal in the east and south of England.[1]

Many attempts have been made to calculate the weight of a Newcastle chaldron as used in medieval and early modern times. Coal industry historian John Nef has estimated that in 1421 it weighed 2,000 lb (907 kg), and that its weight was gradually increased by coal traders due to the taxes on coal (which were charged per chaldron) until 1678 when its weight was fixed by law at 52 12 long hundredweight (5,880 lb; 2,670 kg), later increased in 1694 to 53 long hundredweight (5,940 lb; 2,690 kg).[1]

A London chaldron, on the other hand, was defined as "36 bushels heaped up, each bushel to contain a Winchester bushel and 1 imperial quart (1.1 L; 1.2 US qt), and to be 19 12 inches (495 mm) in diameter". This approximated a weight in coal of around 28 long hundredweight or 3,140 lb or 1,420 kg.[2]

The chaldron was the legal limit for horse-drawn coal wagons travelling by road as it was considered that heavier loads would cause too much damage to the roadways. Railways had standard "chauldron wagons" which were about 10 ft (3.05 m) and around 6 ft 3 in (1.91 m) high.

The value of a chaldron of coal depended on the size of the lumps of coal and also their water content. Unscrupulous merchants would purchase their coal in lumps as large as possible then sell them in smaller sizes. This was abolished by the Weights and Measures Act of 1835, which legislated that from January 1836 coal was only to be sold by weight.[3]

See also


  1. ^ a b Ashworth, William; Mark Pegg (1986). The history of the British coal industry. Oxford University Press. pp. 559–560. ISBN 0-19-828282-6. 
  2. ^ Hutton, Charles (1815). A Philosophical and Mathematical Dictionary. p. 302. 
  3. ^ William J. Ashworth, Charles (2003). Customs and Excise. Oxford University Press. p. 289. ISBN 0-19-925921-6. 

 This article incorporates text from a publication now in the public domainChambers, Ephraim, ed. (1728). "article name needed". Cyclopædia, or an Universal Dictionary of Arts and Sciences (first ed.). James and John Knapton, et al. 

4 Annotations

Michael Robinson  •  Link

Chaldron (measure).
From the Latin caldaria, a caldron, M.F. chaldere, a kettle or pot, M.E. chalder, chaldre. Originally pronounced chalder, later chaldron, although in some areas the older pronunciation was still used in the 19th century.

A measure of capacity for coal, coke and grain which was used in England, Scotland and Wales. In use before the 15th century the standard chaldron of coal was first regulated in 1421 under Henry V, at 32 'bushels', totalling 1 'ton' of 2000lb (907·180kg) and was equal to one twentieth of a 'keel' or 'barge load' of 20 tons ( ). This applied every where except Newcastle upon Tyne, where the chaldron totalled 42 cwt and equalled 1/8 of a 'keel'. Taxes of 2d (1p) per chaldron were calculated as it was loaded aboard ship. By the late 18th century, to avoid tax revenues, the size of the regular chaldron had increased by 240 Lbs. ( ). and the Newcastle chaldron by 1232 Lbs. ( ).

1590 A chaldron of sea coals was 12 'sacks' each containing 4 heaped 'bushels'.

1615. A measure of 32 bushels; when used for coal it was 36 bushels. 138.

1635 Shields, Scotland the chaldron consisted of three 'wain' load and cost 7s. (35p). 122

1676-77 the chaldron was increased to 36 heaped 'bushels' totalling 1 ton ( ) of 2240lb (1016·040kg) or 20 cwt ( ) of 120lb each. The Newcastle chaldron, was a measure containing 53 cwt of coal. The size of a 'chaldron wagon' was (Custom House measurement) was 217·989 cubic ft. and the size of a 'boll', being 976·989 cubic ins. Therefore the chaldron was equal to 22·526 'bolls'. The weight of the 'boll' of coals was 2·35284 cwt ( ). The London chaldron consisted of 36 'bushels' heaped up, each 'bushel' to contain a 'Winchester bushel'. One 'quart' was to be 19½ ins. in diameter externally. It was found by repeated trials that 15 'London Pool Chaldrons' were equal to 8 'Newcastle chaldrons', (Rees's Cyclopedia). Therefore the 'London chaldron' must have equalled 28·266 cwt ( ). Various other estimates were also stated for the 'London chaldron'.

1708 the chaldron contained 36 'bushels'.

1789 Beaument's Treatise on the Coal Trade, 28·266 cwt ( ).

1793 Dr. MacNab, Letters to Pitt. 27·000 cwt ( ).

1829 W. Dickson, Evidence on the Coal Trade. 26·500 cwt ( ).

1847 B. Thompson, Inventions and Improvements 28·462 cwt ( )

"Numerous measurement units were used by the London trade Coal was loaded in the north using the Newcastle chaldron (NCh) - a weight measure, whereas it was unloaded in London using a volumetric measure - the London chaldron (LCh). The LCh was defined as 36 coal bushels, but there was no consensus on exactly how much quantity was contained in this measure. Modern and contemporary estimates have ranged from 288 to 396 gallons, or from 25.7 cwt to 28.5 cwt when measured by weight."

Aashish Velkar, 'Market Transparency, Uniform Measurements and Standardized Quantities: Institutional Change in 19th Century Britain'

Cumsalisgrano  •  Link

The above and the Two URL's below indicate the " why there was great need" for Standards and means and 'weigh[t]s' to enforce them.

The price of a lump of cole be what the customer would put up with and was able to pay .
Caveat emptor at work.
Another factor at work was that coles would have none stardard specific gravities as qualities be very un even.

Bill  •  Link

CHALDER / CHALRON, a quantity of coals containing 36 bushels heaped up, London measure, and 72 at Newcastle.
---An Universal Etymological English Dictionary. N. Bailey, 1675.

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Chart showing the number of references in each month of the diary’s entries.