These drawings cover the period 1893-1908. Most of the drawings are titled, dated, and unsigned. Some are identified as designed or drawn by Emil Herter, or approved by Edison, Herter, or Owen J. Conley. The drawings mostly present details and specifications for components of the equipment used at the Ogden works, including the crushers, dryers, furnaces, bricker ovens, and conveyors. Some drawings show the arrangement and layout of equipment, buildings, and railroads. A few depict proposals for laborers' dwellings, and several pertain to work for the New Jersey Zinc Co. and the Edison Saunders Compressed Air Co. There are nearly 3000 drawings. Most are black ink renderings on white, polished linen, but some are blueprints. A complete listing can be found as an appendix to the finding aid at the Edison National Historical Park. A sample of eight drawings has been reproduced.