Evaluation of the ancient geomagnetic field at the time that this kiln last cooled down, around A.D. 1840, has been made by means of the Thellier technique applied to bricks from the floor. The value obtained, 56 ± 1 μT, is significantly lower than the value expected from contemporary observatory measurements, 64 μT. The difference is consistent with the demagnetizing field expected from the rather strong magnetization of the baked clay.

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