1911 Encyclopædia Britannica/Isodynamic Lines
ISODYNAMIC LINES (Gr. ἰσοδύναμος, equal in power), lines connecting those parts of the earth’s surface where the magnetic force has the same intensity (see Magnetism, Terrestrial).
See also Contour line#Magnetism on Wikipedia; and our 1911 Encyclopædia Britannica disclaimer.
ISODYNAMIC LINES (Gr. ἰσοδύναμος, equal in power), lines connecting those parts of the earth’s surface where the magnetic force has the same intensity (see Magnetism, Terrestrial).