An otheoscope Size:L: 80 x 60cm 'A Hint to Louis Napoleon'

'A Hint to Louis Napoleon'

the print is embossed 'Charles Spencer

Landscape with lake and steam clouds in the middle distance

View of London from One-Tree Hill in Greenwich Park

An otheoscope Size:L: 80 x 60cm 'A Hint to Louis Napoleon'An otheoscope with fixed vanes of oxidised copper and coloured disc above it. An instrument designed for measuring the mechanical effect of radiant energy, a modification of the radiometer. Mounted in a partial vacuum, the central rotor spins when the vanes are exposed to light. Chemist William Crookes (1832 1919) initially believed the vanes with black surfaces were pushed around by pressure from light radiation. This was incorrect and other theories