An early octant with its ivory scale set for 0-95 degrees with a marginal division of 3 additional degrees on each end and the ivory sliding scale on the arm reading from 0-20 minutes. Most impressively, the hand-painted Coat of Arms of Baron Clinton of the East India Company is on the wood case.

There is an ivory inlay blank in the instrument center, and while the instrument measures as stated, the case is 12 ½ x 11 ¼ inches.