Dated 1836-1865. From Scientific apparatus, musical instruments and telegraph equipment, [1834-1875].

Wheatstone’s rotating mirror apparatus or photometer used to measure the velocity of light.  Consists of a clockwork mechanism surmounted by a dial in a circular glass and brass case with a turret containing the rotating mirror.  Housed in a mahogany box with brass winding key.  [See K/PP107/4/1/38.]