Hadley's octant, 1731
An octant on BOT Chain. Pick one of twenty-four stars, take a sight, and stow it when you want the sky back. Gas only.
Vol. 677 · gas only · paper edition
Bring the body down until the horizon sits on the ivory.
The photograph is a museum octant, not this contract. The limb on chain holds a star index, a time, and a short note.
Point at a star. The index arm swings on the ivory, and the noon notice writes the name.