Warner spoke about a number of scientific instrument makers who lived and worked in the Capitol Hill neighborhood during the 19th century, who supplied the needs of the US Coast and Geodetic Survey and a variety of other government and private clients. These highly skilled craftsmen, most of them German immigrants, produced telescopes, surveyor's transits, heliostats and other precision devices that were needed for mapping, astronomy and other scientific pursuits. Among the craftsmen featured in the talk was Edward Kübel, whose workshop in the three hundred block of First Street N.E. produced the heliostat that Albert Michelson used for measuring the speed of light.
Warner is curator of the National Museum of American History Physical Sciences Collection, which includes a number of instruments that were made by Kübel and other Hill manufacturers.
