Sector, English , 19th Century

Ivory 6 inch sector with brass hinge fittings and a retaining pin on each leg; the ivory is cracked near the hinge. Typical English pattern with sine and two tangent sectoral scales on one side, and a double logarithmic scale of numbers and sine and tangent single scales. The reverse has lines, chords and secant sectoral scales and unlabelled inches, inclination of the meridian, chords, latitude and hours as single scales. The outer edge is blank.