The schematic sketch of the conditions of the Clementinum observatory during the magnetic storm on 17 November 1848. The circles with dots in their centres indicate the location of the upward FAC, the circle with a cross mark the position of the downward FAC. The intensity of the electric currents is expressed by means of the boldness of the markers. The dashed lines represent the lines of force of the magnetic field generated by the FACs. The ΔD sign stands for the deviation of the magnetic declination. We suppose that the substorm electrojet then flowed at a magnetic latitude which was lower than the magnetic latitude of Clementinum.