Near simultaneous sharp and intense variations in magnetometer traces at stations spanning a broad range of magnetic latitudes during the 2 September 1859 storm: (top panel) H-component variation at Ekaterinburg; (middle) D-component variation at Rome; (bottom) H-component variation at Colaba. The horizontal bars in the top panel represent levels at which traces went off scale; the dashed lines indicate the successive abrupt positive and negative excursions. The open orange circles in the second panel indicate the normal declination at Rome. Geomagnetic latitudes are for epoch 1860.