Earliest Uses
It is generally accepted that Dorset ball clays - and probably Devon
ball clays too - have been used since Roman times to make crude pottery.
However it was the introduction of tobacco to England in the 16th
century by Sir Walter Raleigh and the need for a suitable clay with
which to make tobacco pipes that led to the start of the modern ball
clay trade.
Although the highly plastic ball clays were ideal for tobacco pipe
manufacture, their expansion and contraction during firing made them
difficult to control in tableware manufacture. Most pottery was made
with easy-to-use local coloured clays. By the 17th century it was
common for jugs, bowls and other tableware made with these clays to
be covered with either a thick white glaze (as in Delft ware) or a
white clay slip coating. From at least the 1650's potters in Bideford
were using a white slip of North Devon ball clay and scratching designs
through the white slip, exposing the coloured body beneath.
Shipments of Dorset tobacco pipe clays from Poole
were significant by the 1630's and were the port's most important
cargo for most of the 17th and 18th centuries, especially to London
and many south coast ports. By 1662 the trade had become sufficiently
important for an Act to be passed forbidding the export of pipe clays
to foreign countries. Shipments of North Devon clay through Bideford
were also important in this period, especially to pipe manufacturers
in Bristol, but shipments of South Devon clays seem to have been relatively
small until the middle of the 18th century.
Important 18th Century Developments
Whilst the Chinese learnt how to make fine white porcelain many centuries
ago, it was only in the 18th century that European potters learnt
how to make good quality white-bodied pottery. They had to overcame
the difficulties of using white firing plastic 'tobacco pipe' clays,
and had to both discover and learn how to use china clays with little
plasticity.
It was the achievements in this area by the famous early potters in
Stoke-on-Trent such as Wedgwood, Astbury and Spode that caused the
demand for ball clays to take off - along with the demand for china
clays. They all needed ball clays from Devon and Dorset - as well
as china clays from Cornwall and Devon - to make their fine 'cream
wares', 'Queen's Ware' and so on.
Josiah Wedgwood's most famous achievement in 'Queens Ware' was
the 952 piece dinner and dessert service with 'Frog' crests made for
the
Empress Catherine the Great of Russia in 1774.
[Image by courtesy of the Trustees of the Wedgwood Museum, Barlaston,
Staffordshire (England).]
A typical recipe for such pottery could have
included equal quantities of ball clay, china clay, flint (a form
of silica) and Cornish Stone (a source of feldspar). Between 1765
and 1785 - at the same time as the industrial revolution in the manufacture
of pottery and the associated 'canal mania' - the annual shipments
from South Devon quadrupled to almost 10,000 tons.
Coade Stone
One of the lesser-known early applications
of ball clay was in the production of a high-grade ceramic known as
Coade Stone. This was first produced in London in 1770 by a Mrs Coade
from Lyme Regis. It was an architectural ceramic of high artistic
and technical quality that has been found to be an exceptionally durable,
artificial 'stone' for building decoration and statuary. Examples
include friezes on Buckingham Palace, fan vaulting in St George's
Chapel, Windsor and the Lion Statue on Waterloo Bridge. A recent detailed
scientific analysis of the 'stone' has confirmed that ball clays from
Devon or Dorset were the major component, together with pre-fired
clay. Mrs Coade died in 1825 and production had ceased by about 1840.
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