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liquid compass 
Instrument with magnets that floats on a liquid; it indicates magnetic north.
pivot
Axle around which the compass card rotates.
sliding cover
Retractable cover that protects the glass dome from scratches when not in use.
bowl
Watertight case containing the magnetic elements, which float in a liquid (oil or alcohol) to reduce oscillations.
compass card
Rotating disk graduated from 0° to 360° and integrated with two magnets; it shows the cardinal points and the points in between.
glass dome
Transparent nondistorting hemispherical cover for the bowl containing the liquid.
