8th Day. Attractive and Directive Powers of Loadstones.
The Form or Position of Filings of Iron at the Poles and Equator of a
Loadstone.
Magnetick Power acts thro' all Bodies but Iron.
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.