The Attraction of different, and Repulse of corresponding Poles.
The manner of touching and untouching of Needles.
The Law of Magnetick Attraction discover'd.
9th—The Phænomena of Terrella, or Spherical Loadstones.
The Direction of Magnetick Needles on the Surfaces of Terrella nearly towards the Poles.
Their Variation East and West.
The Inclinatory or Dipping-Needle, with the Law of the Alteration of that Inclination on the Surface of a Terrella.
The Terrestrial Magnetism consider'd.
The Application of the Dipping-Needle to the Discovery of the Longitude and Latitude of Places by Land and Sea.