Rotary Demisphere (Precision Optics)

Marcel Duchamp · Paris, 1925

Before you is Rotary Demisphere. A painted papier-mâché half-sphere sits on a velvet disk under a plexiglass dome, with a motor and pulley beneath. Set spinning, the flat spiral appears to swell forward into a solid dome. Duchamp spent years on optical devices like this one.

Medium Painted papier-mâché demisphere fitted on velvet-covered disk, copper collar with plexiglass dome, motor, pulley, and metal stand · Dimensions 58 1/2 x 25 1/4 x 24" (148.6 x 64.2 x 60.9 cm) · Credit Gift of Mrs. William Sisler and Edward James Fund

Hanging beside it in The Steven and Alexandra Cohen Center for Special Exhibitions: Fresh Widow, Bicycle Wheel

More by Marcel Duchamp here: Why Not Sneeze Rose Sélavy?, In Advance of the Broken Arm, Network of Stoppages, Landscape, The Chess Players, The Passage from Virgin to Bride