octant and case

Ebony and brass octant with maker's name - H. Duren New York on ivory inset. Ivory Vernier scale and end of pencil. Wooden transport case carries #23 and H. Duren on paper label. Longest side of case measures 12". Brewington's book lists maker as Henry Duren as follows: 1860 machinist; 1861 instrument dealer; 1864 chronometer dealer; 1865 clock dealer; 1869 chronometer dealer. Business located at 39 Burling Slip, New York.