The Magnetic Art

with ink, and having moved the spike more toward the pole or the equator along the same line, you will work as before until you have described the entire meridian, as you see in the figure, because since the magnetic needle always seeks the pole, and these lines are all drawn according to the position of the needle or iron spike, you will be able to describe all the meridians on the magnetic globe with this art. When these have been divided through the middle, the magnetic equator will offer itself, CD, from which circles drawn equidistant will give parallels; thus you will construct the entire magnetic sphere with no less pleasant than subtle artifice. These things having been duly performed, if you place the iron spike over the equinoctial line CD of the magnet,