machine-divided glass plate
Date: 1860-1870
Inventory Number: 2007-1-0547
Classification: Glass Plate
Dimensions:glass plate alone: 38.7 × 38.7 × 1.1 cm (15 1/4 × 15 1/4 × 7/16 in.)
glass plate attached to board: 39.2 × 39.2 × 3.3 cm (15 7/16 × 15 7/16 × 1 5/16 in.)
Description:
A circular green-tinted glass disk is attached to a wooden deck by means of two wooden clasps and two rounded metal clasps. The disk has a beveled limb and a circular aperture in the center. Two concentric scales are very faintly divided around the limb of the disk well away the beveled edge. One is divided every 15 minutes (1/4°) and the other every 6 minutes (1/10°). The purpose of the glass is unknown, but there is little doubt that Temple used his dividing engine to make the marks.
To protect the glass, there is brown paper in between the disk and the panel; it sticks out around the circumference and is visible through the hole in the center. There also two pieces of black paper between the glass and the brown paper.