131.'Evolute' Go and Return Shutter, c. 1887
Signed: '110 VOLUT. R. Gotz. PAT. m 3922'
Vulcanite disc is raised for exposure by a connecting rod, working an eccentric pivot on a wheel, rotated by coil-spring tension (missing), with pneumatic release. To fit over lens of 50 mm diameter. Patented by J. R. Goetz in England in 1887.
Length 120 mm, width 80 mm, depth 20 mm.
Inventory no. 59,512.