[f. THERMOMETER + -GRAPH.) A self-registering thermometer.

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1837.  Macdougall, trans. Graah’s E. Coast Greenland, 20. Mr. Vahl, having, on its [the gale’s] cessation, let down his thermometrograph, found the temperature of the sea, at the depth of 110 fathoms, to be 5°.50, while that at the surface was 6°.3, and the atmosphere’s 8°.6.

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1877.  Knight, Dict. Mech., Thermetograph [sic], a self-registering thermometer, recording the maximum and minimum of temperature in a given time.

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