When the needle which is governed by the magnet points directly
from the north to the south, the number XII at its tail, which is
forked, signifies the north, that number XII which is at its point indicates
the south. The sign VI superior indicates the east, and VI inferior the
west. Further, between each two cardinal points there are always
five others which are not so important. The first two of these directions
are called the prior directions ; the last two are called the posterior, and
the fifth direction Hes immediately between the former and the latter ; it
is halved, and one half is attributed to one cardinal point and one half to the
other. For example, between the northern number XII and the eastern
number VI, are points numbered I, II, III, IV, V, of which I and
view of the subject. The lodestone was well known even before Plato and Aristotle, and is
described by Theophrastus (see Note io, p. 115.) The first authentic and specific mention
of the compass appears to be by Alexander Neckam (an Englishman who died in 1217),
in his works De Utensilibus and De Naturis Rerum. The first tangible description of the
instrument was in a letter to Petrus Peregrinus de Maricourt, written in 1269, a translation
of which was published by Sir Sylvanus Thompson (London, 1902). His circle was divided into
four quadrants and these quarters divided into 90 degrees each. The first mention of a
compass in connection with mines so far as we know is in the Nützlich Bergbüchlin, a review
of which will be found in Appendix B. This book, which dates from 1500, gives a compass much
like the one described above by Agricola. It is divided in like manner into two halves of 12
divisions each. The four cardinal points being marked Mitternacht, Morgen, Mittag, and
Abend. Thus the directions read were referred to as n. after midnight, etc. According to
Joseph Carne (Trans. Roy. Geol. Socy. of Cornwall, Vol. n, 1814), the Cornish miners
formerly referred to North-South veins as 12 o'clock veins ; South-East North-West veins as
9 o'clock veins, etc.
