Others, on the contrary, run from north to south.
A, B, C—VEIN. D, E, F—Seams in the
Rocks.
The seams in the rocks indicate to us whether a vein runs from the
east or from the west. For instance, if the rock seams incline toward the
westward as they descend into the earth, the vein is said to run from east
to west; if they incline toward the east, the vein is said to run from west
to east; in a similar manner, we determine from the rock seams whether
the veins run north or south.
east or from the west. For instance, if the rock seams incline toward the
westward as they descend into the earth, the vein is said to run from east
to west; if they incline toward the east, the vein is said to run from west
to east; in a similar manner, we determine from the rock seams whether
the veins run north or south.
Now miners divide each quarter of the earth into six divisions; and by
this method they apportion the earth into twenty-four directions, which they
divide into two parts of twelve each. The instrument which indicates these
directions is thus constructed. First a circle is made; then at equal
intervals on one half portion of it right through to the other, twelve
straight lines called by the Greeks διάμετροι, and in the Latin dímetíentes,
are drawn through a central point which the Greeks call κέντρον, so that
the circle is thus divided into twenty-four divisions, all being of an equal
size. Then, within the circle are inscribed three other circles, the outer
most of which has cross-lines dividing it into twenty-four equal parts; the
space between it and the next circle contains two sets of twelve numbers,
inscribed on the lines called “diameters”; while within the innermost circle
it is hollowed out to contain a magnetic needle3. The needle lies directly
this method they apportion the earth into twenty-four directions, which they
divide into two parts of twelve each. The instrument which indicates these
directions is thus constructed. First a circle is made; then at equal
intervals on one half portion of it right through to the other, twelve
straight lines called by the Greeks διάμετροι, and in the Latin dímetíentes,
are drawn through a central point which the Greeks call κέντρον, so that
the circle is thus divided into twenty-four divisions, all being of an equal
size. Then, within the circle are inscribed three other circles, the outer
most of which has cross-lines dividing it into twenty-four equal parts; the
space between it and the next circle contains two sets of twelve numbers,
inscribed on the lines called “diameters”; while within the innermost circle
it is hollowed out to contain a magnetic needle3. The needle lies directly
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