Before bone china
Europe spent a century trying to copy Chinese porcelain. England’s answer began, improbably, with ground-up bone.
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For centuries the grandest European tables were laid with silver. Then, from the sixteenth century, porcelain arrived from China in quantity: white, hard, cool to the touch and thin enough to glow. Nothing made in Europe looked like it, and nobody in Europe knew how it was made.
The race for “white gold”
Rulers and merchants spent fortunes on the problem. The answer for hard-paste porcelain — fine white kaolin clay fused with a feldspathic stone at a very high temperature — was found in Saxony, and the Meissen manufactory opened in 1710. Other continental factories followed.
English potters had a different difficulty. In the early eighteenth century they had no known source of the white kaolin that true porcelain needs. So they improvised “soft-paste” porcelains from other ingredients: some with ground glass, some with soapstone, and some with calcined animal bone.
The Bow experiment
At the Bow factory in East London, the painter and manager Thomas Frye took out patents in 1744 and 1749. The second is generally read as covering the use of bone ash in the body. Bow stood close to the cattle markets of London and Essex, so bone was cheap and plentiful.
Bow’s ware was not yet bone china as we now know it. It was a phosphatic soft-paste: a porcelain-like body in which calcium phosphate from bone helped the mixture survive the kiln and fire whiter. Other English factories, including Chelsea in its later years, used bone ash in similar ways.
Look closer: why “soft-paste”?
“Soft” refers to the lower firing temperature and the softer glaze, not to the feel of the finished piece. Soft-paste bodies were difficult: they slumped in the kiln, losses were high and results were inconsistent. That is why the eighteenth-century experiments matter historically but did not yet create a dependable material.
The decisive change came when bone ash was combined with the Cornish china clay and china stone that became available to English potters later in the century.
What changed
By the 1770s and 1780s, English potters could obtain china clay and china stone from Cornwall. Combining those with bone ash produced a body that was harder, more reliable and whiter than the soft-pastes. The man who made that combination a commercial success worked not in London but in the Staffordshire Potteries.
Continue the trail · HistoryJosiah Spode and Staffordshire