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![Diagram of electrotype apparatus as devised by George Mathiot of the CoastSurvey cgs05107.jpg Diagram of electrotype apparatus as devised by George Mathiot of the CoastSurvey](/sites/default/files/styles/max_1300x1300/https/s3.amazonaws.com/s3-east-testmedia-noaa.woc.noaa.gov/dam/Photos/legacy/pl23_cgs05107.jpg?itok=tqqPIVOw)
Description
Diagram of electrotype apparatus as devised by George Mathiot of the CoastSurvey. This apparatus allowed the reproduction of copper-plate engravingseach of which could only survive 500 to a 1000 or so press impressions beforewearing away sufficiently to be useless. This system allowed the production ofthousands of charts via plate copies produced from the original engraving. (Image credit: NARA C&GS; Colllection)