b"Divination: A geophysicist's viewFeatureFigure 7.The Freiberg vein system showing rich silver-lead veins trending N-S and NW-SE (black solid lines); lead-quartz veins (dashed); lead-barite veins (dotted); and barren veins (dots and dashes). After Figure 5.4-9 Economic Mineral Deposits by A.M. Bateman 1959. John Wiley & Sons.in the oxidised zone. Low to moderate erratic conductivity would be the best that the other sulphides could manifest as most of the sulphides were cubic, a habit which is not advantageous for high conductivity when aggregated (see my comments on pyrite in Preview 203 last year). However, the ores had a physical character suggesting that geophysics (magnetics, electromagnetics, resistivity / IP) could be usefully applied, at least indirectly, in exploring for Freiberg type mineralisation. In Agricolas time, however, there were three techniques: visual observation, costeaning (pitting, trenching), and divining, as outlined in Table 1.Figure 8 is a delightfully informative woodcut from Book 2 of De Re Metallica. It depicts, on a hilly site, an interesting cast of characters engaged in prospecting. In the right foreground, two Table 1Summary of 16th Century Prospecting Techniques, Book 2 De Re Metallica. Ag-Pb Fissure Veins, Ore Mountains, Saxony-BohemiaEyeballingDirect RecognitionScree, alluvials, shed from veins Bushfire burn-off, exposed veins Torrential rain, exposed veinsIndirect RecognitionGeobotanical signs: stunted tree growth, tree foliage over veins resists frost damage, particular herbs & fungi grow near & on veinsDiggingSurface Pits To intersectveinsSamplesSurface CosteansDiviningYRods-Forked Twigs: must be right size neither too large nor too smallFigure 6.Top: There were several types of Ore Mountain veins. These are Hazel for Ag min.depicted (from Book 10 of Kirchers Mundus Subterraneus 1678 edition: types Ash for Cu min.of metal veins and mine workings). Vertical (profunda), inclined (obliqua), flat (dilatata), and deep (humilis) veins were encountered. Vertical or steeply Pine for Pb/Sn min.inclined veins were common in the Freiberg field during Agricolas time. Iron/steel for AuAgricolas depiction of outcropping steeply inclined veins vena profunda (profunda deep). Middle: a single vein on the side of a mountain. Bottom: twoProtocolsCorrect grasp of sensing device, random wanderingsmuttered veins traversing steep topography. These deep, steep, veins ranged from 5cm toincantationsover 1.5m in width; the vein spacing ranged from 10s to 100s of metres. From De Re Metallica Book 3, 1556 edition. Result Gyration of twig/rod towards vein51 PREVIEW DECEMBER 2020"