Wedgwood scale

The scale and associated measurement technique were proposed by the English potter Josiah Wedgwood in the 18th century.

The boiling point of mercury limits the mercury-in-glass thermometer to temperatures below 356 °C, which is too low for many industrial applications such as pottery, glass making and metallurgy.

To solve this problem, in 1782, Wedgwood created an accurately scaled pyrometric device, with details published in the Philosophical Transactions of the Royal Society of London in 1782 (Vol.

[9][10] The origin on the Wedgwood scale (0 °W) was set at the onset temperature of red heat, 1,077.5 °F (580.8 °C).

[12] Louis-Bernard Guyton de Morveau used his pyrometer to evaluate the temperature scale of Wedgwood and came to the conclusion that the starting point should be significantly lower, at 517 °F (269 °C) instead of 1,077.5 °F (580.8 °C), and that the steps should be nearly halved from 130 °F (72 °C) to no more than 62.5 °F (34.7 °C).