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Figure 2607 -- Duddell Moving Coil Oscilliograph General view of electromagnet form of Duddell moving-coil oscillograph, showing the oil bath, and electromagnet

with Duddell moving-coil oscillograph, consisting of a large rotating light-shutter wheel and a mirror moved by a cam, to draw marker lines on moving film

2622, 2623 -- Interior of cinematograph camera as used on Duddell moving coil oscillograph for obtaining long records. The loose ends of the case are