History
In 1782, Josiah Wedgwood created accurately scaled pyrometric beads. This led him to be elected a fellow of the Royal Society.
The modern form of the pyrometric cone was developed by Hermann Seger and first used to control the firing of porcelain wares at the Königliche Porzellanmanufaktur (Royal Porcelain Works) in Berlin, in 1886. Seger cones are to this day made by a small number of companies and the term is often used in Europe as a synonym for pyrometric cones. The Standard Pyrometric Cone Company was founded by Dr. Edward J. Orton, Jr. in 1896 to manufacture pyrometric cones, and following his death a charitable trust was established to operate the company.
Commercially produced pyrometric cones replaced glaze cones used by European and American potters in earlier times. Glaze cones were made by evaporating water from a liquid glaze until the resulting mass reached the consistency of a plastic clay. The plastic mixture was then formed into cones that were dried and set in a soft pad of clay in a kiln. When observed through the viewing port of a kiln the potter could see when a glaze cone had reached its melting point. Asian potters used draw rings, rings of clay dipped in glaze, for a similar purpose.The rings were removed from the kiln through special loopholes in the kiln walls using metal rods and examined for signs of melting in the glaze.
Read more about this topic: Pyrometric Cone
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