DIPPING, among miners, signifies the interruption or breaking off the veins of ore; an accident that
gives them a great deal of trouble before they can discover the ore again. A great deal of the skill of the miners consists in the understanding this dipping of the veins, and knowing how to manage in it. In Cornwall they have this general rule to guide them in this respect: most of their tin-loads, which run from east to west, constantly dip towards the north. Sometimes they underlie; that is, they slope down towards the north three feet in height perpendicular. This must carefully be observed by the miners, that they may exactly know where to make their air-shafts when occasion requires; yet, in the higher mountains of Dartmar, there are some considerable loads, which run north and south; these always underlie towards the east. Four or five loads may run nearly parallel to each other in the same hill; and yet, which is rare, they may meet altogether in one hatch, as it were a knot, which well tins the place, and so separate again, and keep their former distances.