II are northern directions lying toward the east, IV and V are eastern directions lying toward the north, and III is assigned, half to the north and half to the east.
One who wishes to know the direction of the veins underground, places over the vein the instrument just described; and the needle, as soon as it becomes quiet, will indicate the course of the vein. That is, if the vein proceeds from VI to VI, it either runs from east to west, or from west to east; but whether it be the former or the latter, is clearly shown by the seams in the rocks. If the vein proceeds along the line which is between V and VI toward the opposite direction, it runs from between the fifth and sixth divisions of east to the west, or from between the fifth and sixth divisions of west to the east; and again, whether it is the one or the other is clearly shown by the seams in the rocks. In a similar manner we determine the other directions.
Now miners reckon as many points as the sailors do in reckoning up the number of the winds. Not only is this done to-day in this country, but it was also done by the Romans who in olden times gave the winds partly Latin names and partly names borrowed from the Greeks. Any miner who pleases may therefore call the directions of the veins by the names of the winds. There are four principal winds, as there are four cardinal points: the Subsolanus, which blows from the east; and its opposite the Favonius, which blows from the west; the latter is called by the Greeks Ζέφυρος, and the former Ἀπηλιώτης. There is the Auster, which blows from the south; and opposed to it is the Septentrio, from the north; the former the Greeks called Νότος, and the latter Ἀπαρκτίας. There are also subordinate winds, to the number of twenty, as there are directions, for between each two principal winds there are always five subordinate ones. Between the Subsolanus (east wind) and the Auster (south wind) there is the Ornithiae or the Bird wind, which has the first place next to the Subsolanus; then comes Caecias; then Eurus, which lies in the midway of these five; next comes Vulturnus; and lastly, Euronotus, nearest the Auster (south wind). The Greeks have given these names to all of these, with the exception of Vulturnus, but those who do not distinguish the winds in so precise a manner say this is the same as the Greeks called Εὖρος. Between the Auster (south wind) and the Favonius (west wind) is first Altanus, to the right of the Auster (south wind); then Libonotus; then Africus, which is the middle one of these five; after that comes Subvesperus; next Argestes, to the left of Favonius (west wind). All these, with the exception of Libonotus and Argestes, have Latin names; but Africus also is called by the Greeks Λίψ. In a similar manner, between Favonius (west wind) and Septentrio (north wind), first to the right of Favonius (west wind), is the Etesiae; then Circius; then Caurus, which is in the middle of these five; then Corus; and lastly Thrascias to the left of Septentrio (north wind). To all of these, except that of Caurus, the Greeks gave the names, and those who do not distinguish the winds by so exact a plan, assert that the wind which the Greeks called Κόρος and the Latins Caurus is one and the same.
