But besides these variations which we have mentioned, there are changes steadily going on, by which the isodynamic, isogonic and isoclinic lines are permanently displaced on the surface of our planet.    From Wordnik.com.  [Outlines of a Mechanical Theory of Storms Containing the True Law of Lunar Influence] Reference

Admitting the existence of two principal solid masses whose general direction is from south to north, and that these masses are more susceptible of permeation by the ethereal fluid than the waters in which they are suspended, we have a general solution of the position of the magnetic poles, and of the isogonic, isoclinic, and isodynamic lines.    From Wordnik.com.  [Outlines of a Mechanical Theory of Storms Containing the True Law of Lunar Influence] Reference

These general remarks will be sufficient to connect the different systems of isoclinic non-parallel lines with the great phenomenon of equilibrium which is manifested in the magnetic equator.    From Wordnik.com.  [COSMOS: A Sketch of the Physical Description of the Universe, Vol. 1] Reference

Their combined action may therefore be graphically represented by three systems of lines, the 'isodynamic, isoclinic', and 'isogonic' (or those of equal force, equal inclination, and equal declination).    From Wordnik.com.  [COSMOS: A Sketch of the Physical Description of the Universe, Vol. 1] Reference

These lines are not parallel to lines of equal inclination (isoclinic line), and the intensity of the force is not at its minimum at the magnetic equator, as has been supposed, nor is it even equal at all parts of it.    From Wordnik.com.  [COSMOS: A Sketch of the Physical Description of the Universe, Vol. 1] Reference

(isodynamic), equal inclination (isoclinic), and equal deviation (isogonic).    From Wordnik.com.  [COSMOS: A Sketch of the Physical Description of the Universe, Vol. 1] Reference