Adams also studied terrestrial magnetism, determined the Gaussian magnetic constants at every point on the Earth and produced maps with contour lines of equal magnetic variation which were published after his death.
Adams-aral din terrestrial-akit, tinutukoy ang Gaussian batubalani constants sa bawat point sa Earth at ginawa ng mga mapa sa ayos ang linya ng pantay na kabigha-bighani ng pagkakaiba-iba na kung saan ay nai-publish na pagkatapos ng kanyang kamatayan.