Compass universally used as compass until the invention of the box-like compass with a 'dry' pivoting needle sometime around 1300. Originally, many compasses were marked only as to the direction of magnetic north, or to the four cardinal points (north, south, east, west). Later, these were divided, in China into 24, and in Europe into 32 equally spaced points around the compass card. For a table of the thirty-two points, see compass points. In the modern era, the 360-degree system took hold. This system is still in use today for civilian navigators. The degree system spaces 360 equidistant points located clockwise
Compass equivalence theorem only a collapsing compass and no straightedge. There are several proofs of the correctness of this construction and it is often left as an exercise for the reader. Here is a modern one using transformations. Compass equivalence theorem The compass equivalence theorem is an important statement in compass and straightedge constructions. The tool advocated by Plato in these constructions is a "divider" or "collapsing compass", that is, a compass that "collapses" whenever it is lifted from a page, so that it may not be directly used to transfer distances. The "modern compass" with its fixable aperture can be used to