Humboldt State University
Robert A. Paselk Scientific Instrument Museum
Chemical Heritage Foundation
The catalog scan above is from the Eimer & Amend Catalog 1910, Chemical Apparatus & Laboratory Supplies, New York (1910). The illustrations are identicle to those in the 1899 Carl Zeiss catalog2 Both forms of this instrument are also described, but not illustrated, in the Henry Heil Chemical Company Illustrated Catalog and Price-List of Chemical Apparatusetc. of 1903. This instrument exhibits a number of evolutionary changes compared to the earlier example of 1893 in this exhibit. Thus the mirror is larger and rectangular to provide more effective illumination of the prisms. The mirror is also held in a heavier, higher quality holder and bracket assembly. The other change is a slightly heavier stand, and the reversal of the orientation of the pillar on the stand. The newer instrument also exhibits the classic Carl Zeiss Jena "achromatic lens" logo, introduced after 19043, instead of the flowing script of earlier instruments (note logo on base in Side view). Finally, the current instrument is provided with the upright style case that became the standard for Abbe refractometers from all manufacturers in the 20th century.
The current design was superceeded in 1911, as seen in the 1920 instrument in this exhibit.
The Abbe refractometer provides a quick and easy means for determining refractive index and dispersion of liquids and solids. Its most common use is the determination of the concentrations of solutions. A brief essay, The Chemical Refractometer, describes the charecteristics, design, and use of these instruments. A detailed history, The Evolution of the Abbe Refractometer, traces the development of this valuable instrument to around 1980.
The instrument stands 12 5/8" high in the closed, vertical position. The entire instrument is constructed of brass, with a heavy, black japanned, cast base (4" x 3 1/4" x 3/4") bolted to a solid nickel plated pillar supporting the rest of the instrument. The scale arm is black japanned with a polished brass or nickel-silver scale (now heavily patinated) with black filled engraved graduations to the third decimal, numbered in the tenths-place from 1,3-1,7, and the hundredths-place in cycles of 0-9. The alidade is nickel plated, with a black painted bracket for the magnifier, and a fiducial line engraved on a small black-oxidized and polished brass pointer. The telescope and telscope bracket are agian nickel-plated, including the dispersion scale and fiducial pointer. A poor attempt to remve corrosion by a previous owner has left the telescope barrel with a badly scratched surfaces, often penetrating the nickel plate. The 2 1/4" x 1 1/2"mirror (partially unsilvered around edges) is held in a well made metal holder. Finally, the prism holder and water-jacket assembly is in originally black enameled brass.
The instrument is in its original light hardwood (maple?) case (15"h x 8 1/4"w x 6 1/2"d), having an age darkened brass carry-handle and nickel plated keyhole cover. The apparently original key is of the "Z-handle" key (the picture is of the key for the Sugar Refractometer in this display). An apparently original thermometer and case is included (note engraved manufacturers signature), along with a glass test-block (nD = 1.5178; 0.788" x 0.474" x 0.156", polished on one side and one end).
1 "Nr. 4255 ... was delivered to Carl Zeiss in Frankfurt/Main in September 24., 1906." Personal communication (2003), Dr. Wolfgang Wimmer, Archivar, Carl Zeiss Jena GMBH.
2 Carl Zeiss Optiche Werkstaette. Specialkatalog über Spectrometer und Refractometer für feste und flüssige körper; hilfsapparate. Carl Zeiss Optiche Werkstaette, Jena (1899) pp 39-43.
3 Company Seven, Carl Zeiss - A History Of A Most Respected Name In Optics. (http://www.company7.com/zeiss/history.html)