The Encyclopedia offers more than 1,500 historical sources, including photographs, drawings, maps, books, catalogues, cartoons, advertisements, posters, newspapers, magazine articles, letters, journal entries, government documents, and legal materials. All of these materials, whether single-page or multi-page resources, are available with the same set of tools for identifying and inspecting the source. (For a fuller description of exploring multi-page historical sources, see the "Reading Bound Volumes" section of the User's Guide.)

The historical source itself occupies the main portion of the screen, with identifying information and a caption below. A vertical bar of viewer controls is available in the lower-right corner of every historical source. (For a description of the index along the left-hand column of the window, see the "Browsing Entry Pages" section of the User's Guide.)

Viewer Controls

All historical sources make use of the Viewer Controls to facilitate exploration of the resource.

This button brings up a thumbnail image of the full image with a red line indicating the portion of the image currently visible. Move the red line to change what is shown.

This button zooms in on the image.

This button zooms out of the image.

This button returns the image to its initial state.

This button changes your cursor to a magnifying glass. Click the cursor on the image to zoom in on that spot.

This button changes your cursor to an open hand. Click on the image and drag to move what is shown in the window on a zoomed image.

This button rotates the image clockwise.

This button rotates the image counterclockwise.