George Shilling (1844–1917) was born and educated in Norway and moved to
the United States in 1867. In 1882, after working in several American instrument
shops, he went into business on his own as a manufacturer of surveying and
astronomical instruments. Shilling’s shop was located in Washington, D.C., and
the federal government was his biggest customer.
Ref: Historical and Commercial Sketches of Washington and Environs
(Washington, D.C., 1884), p. 194.