Bole hill
Encyclopedia
A Bole hill was a place where lead
was formerly smelted
in the open air.
The bole was usually situated at or near the top of a hill where the wind was strong. Totley
Bole Hill on the western fringes of Sheffield
consisted of a long low wall with two shorter walls at right angles to it at each end. At the base of a bole 20 feet (6.1 m) long were laid great trees called blocks. On these were laid blackwork, partly smelted ore about half a yard thick. Then came ten or twelve trees called shankards. On top of these three or four courses of fire trees were laid with fresh ore. This was ignited and burnt for about 48 hours. This smelted lead, which ran down channels provided for the purpose and was cast into sows of about 11 hundredweight
. A single firing produced 16 fother
s of lead (about 18 ton
s) from 160 loads of ore (about 40 tons) and 30 tons of wood. Much of the ore was left incompletely smelted having become blackwork. Some of this was smelted in a foot-pump blown furnace, but some was left to be used when the bole was next fired.
Bole smelting was replaced by smelting in smeltmill
s in the late 16th century. That was in turn replaced by smelting in cupolas, a variety of reverberatory furnace
in the 18th century.
Lead
Lead is a main-group element in the carbon group with the symbol Pb and atomic number 82. Lead is a soft, malleable poor metal. It is also counted as one of the heavy metals. Metallic lead has a bluish-white color after being freshly cut, but it soon tarnishes to a dull grayish color when exposed...
was formerly smelted
Smelting
Smelting is a form of extractive metallurgy; its main use is to produce a metal from its ore. This includes iron extraction from iron ore, and copper extraction and other base metals from their ores...
in the open air.
The bole was usually situated at or near the top of a hill where the wind was strong. Totley
Totley
Totley is a suburb on the extreme southwest of the City of Sheffield, in South Yorkshire, England. Lying in the historic county boundaries of Derbyshire, Totley was amalgamated into the city of Sheffield in 1935, and is today part of the Dore and Totley electoral ward in the city, though it remains...
Bole Hill on the western fringes of Sheffield
Sheffield
Sheffield is a city and metropolitan borough of South Yorkshire, England. Its name derives from the River Sheaf, which runs through the city. Historically a part of the West Riding of Yorkshire, and with some of its southern suburbs annexed from Derbyshire, the city has grown from its largely...
consisted of a long low wall with two shorter walls at right angles to it at each end. At the base of a bole 20 feet (6.1 m) long were laid great trees called blocks. On these were laid blackwork, partly smelted ore about half a yard thick. Then came ten or twelve trees called shankards. On top of these three or four courses of fire trees were laid with fresh ore. This was ignited and burnt for about 48 hours. This smelted lead, which ran down channels provided for the purpose and was cast into sows of about 11 hundredweight
Hundredweight
The hundredweight or centum weight is a unit of mass defined in terms of the pound . The definition used in Britain differs from that used in North America. The two are distinguished by the terms long hundredweight and short hundredweight:* The long hundredweight is defined as 112 lb, which...
. A single firing produced 16 fother
Fother
Fother is an old unit originally a cart-load , but through transference became a measurement for a quantity of lead. It was defined in different ways at different places and times, being about equal to a ton or somewhat more....
s of lead (about 18 ton
Ton
The ton is a unit of measure. It has a long history and has acquired a number of meanings and uses over the years. It is used principally as a unit of weight, and as a unit of volume. It can also be used as a measure of energy, for truck classification, or as a colloquial term.It is derived from...
s) from 160 loads of ore (about 40 tons) and 30 tons of wood. Much of the ore was left incompletely smelted having become blackwork. Some of this was smelted in a foot-pump blown furnace, but some was left to be used when the bole was next fired.
Bole smelting was replaced by smelting in smeltmill
Smeltmill
Smeltmills were water-powered mills used to smelt lead or other metals.The older method of smelting lead on wind-blown bole hills began to be superseded by artificially-blown smelters. The first such furnace was built by Burchard Kranich at Makeney, Derbyshire in 1554, but produced less good lead...
s in the late 16th century. That was in turn replaced by smelting in cupolas, a variety of reverberatory furnace
Reverberatory furnace
A reverberatory furnace is a metallurgical or process furnace that isolates the material being processed from contact with the fuel, but not from contact with combustion gases...
in the 18th century.
Further reading
- D. Kiernan and Robert van de Noort, 'Bole smelting in Derbyshire' in L. Willies and D. Cranstone (eds.), Boles and Smeltmills (Historical Metallurgy Society, 1992), 19-21.
- Other articles in the same work.
- R. F. Tylecote, A History of Metallurgy (2nd edn, Institute of Materials, London 1992), 90 113.