On April 2007 the deployment was concentrated along the 210 magnetic meridian, which means north and south of Japan.

Dip (δ) - the angle between magnetic meridian and geographical meridian.

The magnetic meridian is an equivalent imaginary line connecting the magnetic south and north poles and can be taken as the magnetic force lines along the surface of the earth.

To obtain the natural electricity, experimenters would thrust two metal plates into the ground at a certain distance from each other in the direction of a magnetic meridian, or astronomical meridian.

In 1918 T. Lindsay Galloway read a paper to the Institute of Mining Engineers entitled 'A method of determining the magnetic meridian as a basis for mining surveys'.