Peter King, ‘The production and consumption of bar iron in early
modern England and Wales’ Economic History Review, 58.1 (2005),
pp. 1-33.
The figures and tables in the above paper for the most part reproduce data set out in
the appendices to the author’s unpublished thesis, ‘The Iron Trade in England and
Wales 1500-1815: the Charcoal Iron Industry and its Transition to Coke’ (Ph. D.
thesis, Wolverhampton University 2004).
Copies of all computational files (but without formulae etc.), the thesis text, and other
related documents are held by the AHDS.
Any one, wishing to re-examine the computations in detail, will need to obtain a copy
of the CD-ROM appended to King, ‘Iron Trade’, which includes all such files (and
more). This is available from the author.
A. Raw data:
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List of bloomery forges : King, ‘Iron Trade’, appendix 9. This list consists of
known sites of bloomery forges, also known as bloomsmithies (or just smithies).
These were water-powered ironworks, reducing iron ore to the metal in the solid
state. They were probably introduced to England and Wales in the fourteenth
century, but began to be replaced by a blast furnaces and finery forges from
c.1490. However the process remained in use in northwest England until the 18th
century. The data have been collected from a wide range of sources.
Nevertheless, the list is almost certainly incomplete, due to a lack of surviving
source material, and because much of the period was before that studied for the
thesis, and concerned a process that was relatively insignificant subsequently.
This list may need substantial revision in the future, but this is unlikely
significantly to affect the conclusions of the author’s article.
List of Wealden forges: King, ‘Iron Trade’, appendix 10. About 1490, a new
process was introduced. First pig iron was made in a blast furnace, then (so far as
not used to make finished goods of cast iron) this was remelted and fined in a
finery forge to make bar iron. The data here are largely taken From H. Cleere and
D. Crossley, the Iron Industry of the Weald (2 edn, Cardiff 1995), as
supplemented (mainly for the 18th century) by P. W. King, ‘Bar iron production
in the Weald in the early 18th century’ Wealden Iron 2 Ser. 22 (2002), 26-35.
Where dates are given as ‘0’, the dates of operation are unknown.
List of Wealden furnaces: King, ‘Iron Trade’, appendix 11 This is the counterpart
for blast furnaces of the list of Wealden Forges, and relies on substantially the
same sources.
List of finery forges elsewhere: King, ‘Iron Trade’, appendix 12. This represents
the first publication of any reasonably comprehensive list of finery forges for
periods before the 18th century, when there are a series of contemporary lists. For
those lists see E. W. Hulme, ‘The statistical history of the iron trade’
Transactions of the Newcomen Society 9 (1928-9), 12-33 and P. W. King, ‘Early
Statistics for the iron industry: a vindication’ Historical Metallurgy 30(1) (1996),
23-46.
The other sources for this compilation are far too many and varied to be fully
described here. The most important are the archives of landed estates that were
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6.
the landlords of ironworks, not only leases, but also rentals and surveys, and
descriptions in estate title deeds. This is supplemented by references to one
ironworks (as a supplier of raw materials or a customer) in the accounts of
another, and from evidence of other aspects of trade. Land tax assessments
(which survive for most counties between 1780 and 1830) have often been useful
for determining closure dates. This remains to some extent work in progress; in
some cases, further sources have been come to light, which have altered the
author’s views slightly since the submission of his thesis in April 2003. Such
changes (which are not reflected in these data), have usually concerned the
ownership of a forge, rather than its dates of operation..
This body of work is intended to form the basis of a series of books on the
charcoal iron industry of which the latest drafts (at the time that the author’s
thesis was completed) form part of a CD-ROM appended to his thesis. Its
primary objective was to work out who owned each ironworks and at what dates,
and how the various ironworks related to each other in terms of trading
relationships and competition. However any available data were collected that
indicated the output of an ironworks. The most important source of output data
are the lists and surviving accounts, but output may also be indicated by the
quantity of wood (for charcoal) bought or the quantity of pig iron supplied to a
forge; in both cases, the existence of other sources cannot be ruled out and the
resultant figure accordingly will be a minimum output. The software used for the
calculations allowed for one period of temporary closure; for few forges, there
were two such periods, the second being dealt with by treating it as a separate
forge. In other cases, output data was apportioned, where aggregated in a list.
Most entries in occupy two lines. The first consists of the name, location and
dates of the forge (with its regional classification). The second contains a series
of dates and numbers: 1716/150 means that the forge made (or is estimated to
have made) 150 tons of bar iron in c.1716. This may be followed by a comment,
or there may be a comment on the next line.
List of blast furnaces elsewhere: King, ‘Iron Trade’, appendix 15. This derives
from the same body of work that has been described for forges in the preceding
section. However, there is must less 18th century output data. Furthermore, the
size of blast furnaces was growing in the preceding period, their output data has
thus been found to be of limited use in estimating the size of the industry. The
data is primarily used in the article to count the numbers of charcoal and coke
blast furnaces respectively. Its use is indicated in the final column, but otherwise
the conventions are similar to those for finery forges. Where an ironworks
contained several blast furnaces, they are listed as separate ones but at the same
location. Temporary closure dates have been adjusted so that the number in use at
the date of a list conforms to it, but this should not be taken as evidence of which
furnace was actually out of blast. The software used for the calculations allowed
a charcoal furnace to be converted to coke, but not vice versa. In one case
(Cleator), the list indicates that a charcoal furnace was ‘built’ when a coke one
‘closed’; this is of course the same furnace, but now using charcoal.
List of melting fineries: King, ‘Iron Trade’, appendix 14. Melting fineries
existing in c.1790 are listed in Birmingham City Archives, B & W, MII/5/12. A
limited amount of data from other sources has also been used. These melting
fineries seem to be for the process often referred to today as ‘potting and
stamping’. Where the ‘closed or converted’ date is not identical with the closed
date, it was subsequently used as a puddling furnace; there is thus some data on
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8.
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them, but all data after 1790 is also incomplete. The ‘pig yield’ is the amount of
pig iron (in cwt.) required to make a ton of bar iron. The lower (better) figure
refers to works (in the Midlands) that were using Wright and Jesson’s process;
the higher to ones, which were still using the original (less efficient) one patented
by Charles Wood.
List of slitting mills: King, ‘Iron Trade’, appendix 16. The contents of this list
have not been used at all in the calculations for the article, but it is included to
show that the ironworks have been intentionally excluded from them, because
they were not finery forges.
List of other ironworks: King, ‘Iron Trade’, appendix 17. The contents of this list
have also not been used at all in the calculations for the article, but the list is
again included to show that the ironworks have been intentionally excluded from
the calculation. The list includes plating forges (which are water-powered but did
not make iron), tinplate works, and spurious claims of the existence of a forge. It
also includes forges with a balling furnace, but no finery or melting finery. These
seem to have been used to recycle scrap, rather than to make iron. The production
of iron from scrap has been excluded from the calculations.
Import data from Customs Accounts and Port Books: King, ‘Iron Trade’,
appendix 18. Before 1697, no trade statistics were officially compiled.
Accordingly, data has to be obtained from records compiled in connection with
the collection of Customs duty. These fall into two groups – Customs Accounts
(PRO, E 122) and Port Books (PRO, E 190). The former were part of the formal
process by which the Customs officers in head-ports accounted to the Exchequer,
while the latter were provided by all ports, in theory to enable the accounts to be
checked. A large number of each has been examined. The list includes some 18th
century data (which has not been used for calculations). For technical reasons in
connection with the calculation it has been necessary to insert certain null entries,
to avoid the results being distorted, where the import figure for a particular port is
included in that for another.
B. Compilations:
10. Production of iron in finery forges. This is figure 1 of the article and the
underlying data. It has been prepared by applying certain multipliers to the
number of Wealden forges and interpolating the data on forges elsewhere. The
Regional classification system used operates at three levels, region, district, and
group; see King, ‘Iron Trade’, Appendix 7.
11. Iron production in melting fineries. This is figure 2 of the article and the
underlying data.
12. Output estimates. A. reproduces figure 3 of the article and the underlying data.
Note also a version of the graph with a different scale on the y-axis. The growth
rates of the total, calculated over 7 and 21 years, are also given. B is the data in
table 1 of the article, but for every year, not every fifth or tenth year. The same
bar iron production section is the same as the previous dataset, but with furnace
data alongside. The calculations in respect of pig iron in the 18th century are
intricate, and are not shown.
13. English bar iron imports: King, ‘Iron Trade’, appendix 19. This is the data
underlying figure 6 of the article. It incorporates the result of interpolating import
data collected from Customs Accounts and Port Books, together with data for
Gothenburg and the Baltic from Scandinavian sources, and data from the
Customs Ledgers (PRO, CUST 5 and 16). Data for 1790 to 1808 have been
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recovered by deducting Scottish data (PRO, CUST 15) from those for Great
Britain (PRO CUST 16). Data for 1705 and 1813 (which is missing) has been
interpolated.
14. Bar iron re-exports and exports from 1697: King, ‘Iron trade’, appendix 20. The
sources are PRO, CUST 5, 15, and 16 (as for imports). Exports were insignificant
until the 1790s.
15. Exports of wrought iron and of nails in the 17th century: King, ‘Iron Trade’,
appendix 21. This consists of modest amounts of data extracted from mid and late
17th century port books and other sources.
16. Production and consumption estimates: King, ‘Iron trade’, appendix 23. This is
the data lying behind figure 8 of the article; it is the same as in table 2 of the
article, but for every year, not every fifth or tenth year
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