Sketches of early filaments.  Numbers 1 and 2 were made by Francis Jehl and the third was added by Edison.  Edison’s writing can be seen at the top and down the right side as, ‘OK, T.A.E.’; ‘This is cotton thread’; ‘about this size. E.’ Sketch number 1 shows the lamp as it appeared in the patent drawing and sketch number 2 filament preceded number 1.
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