Pyrometry is a method of measuring temperatures. Pyrometry usually refers to temperatures that are too high to be measured by ordinary thermometers. It is important in the heat treatment of metals and in the production of glass. One kind of pyrometer matches the color of an object in a furnace against known temperatures of red-hot wires. Another kind, a thermoelectric pyrometer, produces an electric signal that indicates the temperature. Manufacturers use a thermoelectric pyrometer when the temperature is to be recorded graphically or as part of a system that controls the temperature automatically.
In a pottery kiln, where it is also necessary to measure the effect of the heat, pyrometric cones, also known as Seger cones, are sometimes used. These are small, pyramid-shaped cones made of clay and salt. They will melt after being at a certain temperature for a given length of time. Clay rings are also used in kilns to measure the work done by heat.
