Barbara Ellmerer

But here we notice another curious fact … * [ZB Magnet 2] William Gilbert, De Magnete (London: Petrus Short, 1600), Zentralbibliothek Zürich, Alte Drucke und Rara, XVI.28, p. 133.

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Barbara Ellmerer

*System for Prediction of Environmental Emergency Dose
SPEEDI, designed to predict the dispersal of radioactive materials based on forecasts by ERSS, is likely to have delayed the effective evacuation of residents in Fukushima Prefecture. The systems’ failure casts doubt on the government’s disaster-prevention policy, which said that the systems should be used to analyze and predict the amount and spread of radioactive material into the environment during a nuclear crisis.

Long loadstone with versoria. Versoria deviate according to the distance from the middle or equator of the loadstone (CD). The deviations are greater the greater the distance of the versoria is from the equator. [ZB Magnet 2] William Gilbert, De Magnete (London: Petrus Short, 1600), Zentralbibliothek Zürich, Alte Drucke und Rara, XVI.28, p. 164.

[ZB Magnet 2] William Gilbert, De Magnete (London: Petrus Short, 1600), Zentralbibliothek Zürich, Alte Drucke und Rara, XVI.28, p. 155.
AB is a terrella imperfect in parts and of unequal power on the circumference. The needles H and L vary, because they are placed in a decayed part and incline towards the sound parts (where the needles C, D, E, F are placed). Needle O does not deviate because it is placed in the middle of the decayed part.

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[ZB Magnet 2] William Gilbert, De Magnete (London: Petrus Short, 1600), Zentralbibliothek Zürich, Alte Drucke und Rara, XVI.28, p. 96.
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[ZB Magnet 2] William Gilbert, De Magnete (London: Petrus Short, 1600), Zentralbibliothek Zürich, Alte Drucke und Rara, XVI.28, p. 158.

Deviation* is due to Earth’s Elevation. Gilbert explains this thesis with his “terrella” (a spheric magnet). He adds mass to the terrella and observes that a needle is “attracted out of the true direction”. [ZB Magnet 2] William Gilbert, De Magnete (London: Petrus Short, 1600), Zentralbibliothek Zürich, Alte Drucke und Rara, XVI.28, p. 157.

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Judith Albert