Fig. 1.


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Greenwich Observatory magnetometer traces (horizontal force on top and declination on the bottom; the two traces are offset by 12 h) during the time of the solar flare on 1 September 1859. The red arrows indicate the magnetic crochet or SFE. The writing at the bottom in the red box says “The above movement was nearly coincidental in time with Carrington’s observation of a bright eruption on the Sun. Disc[overed] over a sunspot. (H.W.N., 2 Dec 1938)”. H.W.N. refers to Harold W. Newton, Maunder’s successor as the sunspot expert at Greenwich. (From Cliver & Keer 2012, with permission of Solar Physics.)

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