2.25 x 2.4 inch, 45° prism in swing-away mount
Date: 1875-1925
Inventory Number: 1997-1-1699
Classification: Prism
Dimensions:7.2 × 12.2 × 8.4 cm (2 13/16 × 4 13/16 × 3 5/16 in.)
Description:
45° prism with face of 5.5 x 6 cm. The prism is held in a blackened brass mount that has a hinged bracket along one edge. The bracket is designed to be attached to a piece of apparatus. The edge of the prism opposite the bracket has a tab that serves as a handle to swing the prism out of the way of the light beam.
The face of the prism between the hinged bracket and handle is exposed. The adjacent face (at right angles to the first) has a cover that swings out of the way. Its handle is a small screw threaded into it. The rear face of the prism is encased in the brass mount as are the top and bottom.