Octant

device · 1731 · Early modern era

Hadley’s reflecting angle gauge — the forerunner of the sextant.

Inventors: John Hadley, Thomas Godfrey.

What it is made of

Mirror — has part. Two mirrors.

Principles and materials it uses

Wood — is made of. Octants are wooden (ebony).
Brass — is made of. With a brass scale.

History: what it evolved from and what it influenced

Davis quadrant — evolved from. Reflecting angle gauges.
Sextant — evolved into. The sextant is an extended octant.

Take Octant apart