Peter Plancius. _See_ Plancius.
Petrus Apponensis. _See_ Abano, Pietro di.
Petrus Nonius. _See_ Nonius or Nunez.
Philolaus, 214.
Philostratus, 111.
Pictorio, G., 6, 49.
_piedramant_, 11.
Plancius, Peter, *v _bis._
planets, influence of, 20, 137, 142.
plasters, magnetick, 32, 33.
Plato, 3.
in the _Io_, discusses name and properties of the magnet, 1, 9, 11, 18.
in the _Timaeus_, suggests the theory of circumpulsion, 61.
his Atlantis, 159.
on life in the universe, 208.
Pliny (C. Plinius Secundus).
on loadstone fables, 1, 2, 9, 18.
his mistake about Aethiopian loadstones, 17.
on the five kinds of loadstones, 9.
on the alleged discovery of the loadstones, 8.
on the alleged magnetick mountains, 18.
on a locality where loadstone was found, 11.
on the occurrence of iron in Spain, 25.
on the Sagda and the Catochites, 111.
on the silver denarius of Antony, 110.
on the use of loadstone by glass-makers, 111.
on the shadow of a gnomon of a sun-dial at Rome, 213.
Plotinus, 218.
Plutarch, Claudius.
on the garlick fable, 32.
says something flammable exists in amber, 54.
his theory of circumpulsion, 3, 62.
polarity. _See_ verticity.
pole, the, elevation of, 200, 213.
poles, magnetick, of a loadstone, 13, 41, 72, 81, 144.
poles are not points, 12, 41, 72, 96.
Polo, Marco, 4.
Porta, Joannes Baptista (Giambattista della Porta).
his narration of marvels, 6.
on various tempering of iron, 24.
asserts loadstone a mixture of stone and iron, 63.
on his assertion that loadstones have hairs, 66.
asserts vapour to be cause of attraction, 67.
his error as to change of verticity, 73.
suspends iron upwards by a thread, 92.
his error as to centre of the orbe of virtue, 95.
his error as to the polarity which causes repulsion, 102.
his error as to magnetick opposing forces, 103.
experiment with a balance, 108.
his error as to iron being intoxicated, 138.
his error as to iron excited by a diamond, 143.
his error as to the pointing of a magnet, 144.
proportion between loadstone and iron, 149.
his error as to variation and longitude, 166.
praecession of the Aequinoxes, 234, 236.
_primum mobile_, the, 79, 214, 216, 218, 220, 226, 232, 237.
prostaphaeresis, 174, 236.
Prutenical Tables, the, 235.
Ptolemaeus, Claudius.
on loadstone fables, 2, 32.