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].