Accessories include three objectives, five eyepieces (two pairs for use as a binocular), diaphragm wheel, condenser with diaphragm wheel, analyzer, polarizer, objective-mounted side reflector, stage forceps, live-box, compressor, and additional filters and fittings.

The Aug. 15, 1876 patent describes the fine adustment mechanism and a novel swinging substage which allows extreme oblique illumination and which was very influential for the further development of the microscope during the latter part of the 19th century. For example, see the Ross-Zentmayer Student Model elsewhere on this website.

The American Centennial model was first exhibited by Joseph Zentmayer (1826-1888) at the Centennial Exposition in Philadelphia in 1876. The example shown here was made shortly after this date. As quoted by S. H. Gage in Microscopy in America (1830-1945), 1964 in a letter dated 1938 from Arthur H. Thomas (a Philadelphia instrument supplier) to H. N. Ott of the Spencer Lens Co. in reference to the binocular version of this microscope, it was stated that "there were forty-four of these instruments made in all, and they are now museum items".

The American Centennial model is considered by many the finest American microscope manufactured in the 19^th century. Prior to the introduction of the American Centennial, the Grand American model was the top-of-the-line microscope produced by the firm.

See the article written by Zentmayer entitled "What I Know About Late Improvements of the Microscope" published in the  Journal of the Franklin Institute, LXXXIV, 1877.

An 1880 Zentmayer advertisement:

Biographical Sketch of Joseph Zentmayer