Dip Compass

device for determining the elements of occurrence of a bed of rock: directions of trend and dip and the magnitude of the angle of dip. It is a combination of a compass and a plumb; they are secured on a rectangular aluminum or brass plate that has the long side parallel to a N-S direction. The dial is divided into 360° in a counterclockwise direction. The positions of east and west are switched. In order to determine the angle of dip of a bed, the dip compass is placed on its edge on the surface of the bed, perpendicular to the plane of the rock bedding so that the letter N is turned in the direction of the line of dip and the plumb shows the largest possible angle on the dial. This angle will be the angle of dip of the bed. A line drawn on the surface of the rock along the edge of the compass will be the line of dip. The line that is perpendicular to the line of dip shows the trend of the bed. In order to determine the azimuth of this line, the base of the compass is placed on it horizontally in such a way that the N-S line coincides with the trend line; then the azimuth of the bed’s line of trend is read on the dial at the point where the north end of the magnetic needle meets the circle dial.

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