When measuring the direction of a fixed object: Step 1: Lay the compass flat so that the edge of the compass is close to or parallel to the edge of the measured object. Step 2: Slide the turntable to make the hairpin head of the magnetic needle match the two points on the red line of the compass base. Step 3: Locate the reading direction of the layer pressed by the transparent line.
Measure the direction of furnace: level the compass. Near the edge of the stove. If the furnace is made of iron, it will affect the swing of the magnetic needle, so it should retreat two or three feet vertically. The edge of the compass is parallel to the edge of the stove. Slide the turntable so that the hairpin head of the magnetic needle matches the two points on the red line. Reading direction.
It is very important that the end of the magnetic needle with a small hole must coincide with the two little red dot on the red line, and the positions cannot be lost. At this time, it shows that the fishing line (horizontal line) sitting in the square intersects with the layers of the inner plate. All kinds of data and information we are looking for are displayed in the area where this fishing line passes through and covers.