e Ile Coruo, which is the furthest Ile of the Azores Westwarde,
he placeth the Pole of the Lodestone in the seuentie seuen degree of
Latitude."

Further, in the chapter on _The Arte of Nauigation_ in the same work (p.
332, _ed. citat._), Blundevile says:

"But whereas Mercator affirmeth that there should bee a mine or great rocke
of Adamant, wherunto all other lesser rockes or Needles touched with the
Lodestone doe incline as to their chiefe fountaine, that opinion seemeth to
mee verie straunge, for truely I rather beleeue with Robert Norman that the
properties of the Stone, as well in drawing steele, as in shewing the North
Pole, are secret vertues given of GOD to that stone for mans necessarie vse
and behoofe, of which secrete vertues no man is able to shewe the true
cause."

The following is one of the inscriptions in the compartments of the great
Chart of Mercator entitled _Ad Usum Navigantium_, published in 1569:

"Testatur Franciscus Diepanus peritissimus nauarchus volubiles libellas,
magnetis virtute infectas recta mundi polum respicere in insulis C.
Viridis, Solis, Bonauista, et Maio, cui proxime astipulantur qui in
Tercera, aut S. Maria (insulae sunt inter Acores) id fieri dicunt, pauci in
earundem occidentalissima Corvi nomine id contingere opinantur. Quia vero
locorum longitudinis a communi magnetis et mundi meridiano iustis de causis
initium sumere oportet, plurium testimonium sequutus primum meridianum per
dictas C. Viridis insulas protraxi, et quum alibi plus minusque a polo
deuiante {15} magnete polum aliquum peculiarem esse oporteat quo magnetes
ex omni mundi parte despiciant, euum hoc quo assignaui loco existere
adhibita declinatione magnetis Ratisbonae obseruata didici. Supputaui autem
eius poli situm etiam respectu insulae Corui, ut iuxta extremo primi
meridiani positus extremi etiam termini, intra quos polum hunc inueniri
necesse est, conspicui fierent, donec certius aliquod nauclerorum
obseruatio attulerit."

Not all the map-makers were as frank as Paulus Merula, the author of a
_Cosmographia Generalis_, printed by Plantin in 1605, at Leyden. For in the
description of his _tabula universalis_ (_op. citat._ lib. iii., cap. 9) he
says that he does not believe in the magnetic islands; but that he has put
them into his chart lest unskilful folk should think that he had been so
careless as to leave them out!

In the well-known myth of Ogier the Dane, immortalized by William Morris in
the _Earthly P