BOOK III.

73

A— Solid vein. B —Solid stringer. C — Cavernous vein. D —Cavernousstringer. E— Barren vein. F —Barren stringer.

But to return to veins. A great number of miners consider 8 that thebest veins in depth are those which run from the VI or VII direction of theeast to the VI or VII direction of the west, through a mountain slope whichinclines to the north ; and whose hangingwalls are in the south, and whosefootwalls are in the north, and which have their heads rising to the north,as explained before, always like the footwall, and finally, whose rockseams turn their heads to the east. And the veins which are the next

8 The following from Chapter iv of the Nutzlich Bergbiichlin (see Appendix B) mayindicate the source of the theory which Agricola here discards :—“ As to those veins which‘ are most profitable to work, it must be remarked that the most suitable location for the vein" is on the slope of the mountain facing south, so its strike is from vn or vi east to vi or“ vii west. According to the above-mentioned directions, the outcrop of the whole veinshould face north, its gesteins ausgang toward the east, its hangingwall toward the south,an< 3 its footwall toward the north, for in such mountains and veins the influence of the' t Planets is conveniently received to prepare the matter out of which the silver is to be made« ? l° rmec l- • • • The other strikes of veins from between east and south to the region

(< “ e tween west and north are esteemed more or less valuable, according to whether they are(I ne arer or further away from the above-mentioned strikes, but with the same hanging-«< 'T al1, In-wall, and outcrops. But the veins having their strike from north to south,„ tneir hangingwall toward the west, their footwall and their outcrops toward the east,„ are better to work than veins which extend from south to north, whose hangingwalls„ ar ® toward the east, and footwalls and outcrops toward the west. Although the latter“ Tn inS someti P es yield solid and good silver ore, still it is not sure and certain, becausethe whole mineral force is completely scattered and dispersed through the outcrop, etc.”