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].