This special compass is signed G.H.
It contains 3 layers.
Layer 1. is the compasbox itself. Paper scale 1 -24 (hours?)
Layer 2. is the large circle with the 360 degrees. But watch how.
Layer 3 is the bottem piece, the arrow.
Purpose????
I found some explanation:
Hours:
Some old German and Austrian survey compasses feature a graduation in 24 hours or twice 12 hours), sometimes together with a 360 degrees scale
The hour used to be the unit on miners compasses. One hour being the 24th part of the circle (or a full revolution of the Earth), it equals (360/24) 15°. This unit is divided into halves, quarters and so forth down to 1/16 (i.e. 96 units in a right angle). Relative precise measurements could be done by using fractions. It has disappeared on miners compasses but the graduation featuring twice 12 hrs is still in use on geologists compasses.
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