<< >>
Usage conditions apply
This unusual instrument is probably best described as a precise level with a graduated horizontal circle. The telescope is provided with a long and graduated level vial, and an ingenious clamp and tangent screw moving against the silvered vertical arc controls its elevation. This arc extends 20 degrees either way, and is graduated to 10 minutes and read by vernier to 20 seconds. The horizontal circle is silvered, graduated to 15 minutes, and read by opposite verniers with reflecting glasses and magnifiers to 30 seconds. A trough compass and a circular level are mounted above the horizontal circle. The signature reads "Wm. Würdemann, Washington, D.C. 565."
The U. S. War Department transferred this instrument to the Smithsonian in 1931, in a pine box marked "Capt. M. C. Meigs, Washington Aqueduct -Wurdemann--Grading Transit--1854." It was used by Montgomery C. Meigs, the captain in the U. S. Army Corps of Engineers who was tasked with surveying the course of a new Washington Aqueduct in 1853. Since William Würdemann was the leading mathematical instrument maker in Washington at that time, it is reasonable that he was asked to make instruments for this important task.
Currently not on view
Object Name
date made
Würdemann, William
place made
United States: District of Columbia, Washington
overall: 8 1/2 in; 21.59 cm
horizontal circle: 5 1/2 in; 13.97 cm
needle: 4 1/4 in; 10.795 cm
telescope: 11 1/4 in; 28.575 cm
level: 5 1/2 in; 13.97 cm
overall: 8 7/8 in x 12 1/2 in x 6 1/2 in; 22.5425 cm x 31.75 cm x 16.51 cm
ID Number
accession number
catalog number
Credit Line
War Department
See more items in
Medicine and Science: Physical Sciences
Measuring & Mapping
Surveying and Geodesy
Data Source
National Museum of American History
Nominate this object for photography.   

Our collection database is a work in progress. We may update this record based on further research and review. Learn more about our approach to sharing our collection online.

If you would like to know how you can use content on this page, see the Smithsonian's Terms of Use. If you need to request an image for publication or other use, please visit Rights and Reproductions.


Add a comment about this object