[4] Mechanics Magazine, 1830, vol. 13, pp. 114-115 and frontispiece.
[5] See p. 184 for a list of Holcomb’s instruments in the U.S. National Museum.
[6] H. C. King, The History of the Telescope, London, Charles Griffin, 1955, pp. 246-248. Milham op. cit. (footnote 3), p. 10.
[7] As reported in the Journal of the Franklin Institute for July 1834, new ser. vol 14 (whole no. 18), pp. 169-172; July 1835, new ser. vol. 16 (whole no. 20), pp. 11-13; and August 1836, new ser. vol. 18 (whole no. 22), p. 110. The first two of these are given in the appendix, pp. 181-184.
[8] Reported by “R. K. M.” in Sky and Telescope, March 1942, vol. 1, p. 21. The “Catalog of Objectives Made by Henry Fitz,” the time span of which is unspecified, lists 428 objectives up to 13 inches and only 6 mirrors. It is not clear, however, that these represent finished units.
[9] Langley’s work at the Allegheny Observatory, particularly his invention of the bolometer, brought him international reknown as a scientist. In January 1887 he was appointed assistant secretary of the Smithsonian Institution, and later in that year became its third Secretary, serving from 1887-1906.
[10] The giant mirrors of Herschel (1789) and Rosse (1842) were made of an alloy of 71% copper and 29% tin, and 68½% copper and 31½% tin, respectively. This alloy was known as “speculum metal.” The silvered glass mirror was pioneered by Steinhill and Foucault in 1856. In England Dr. A. A. Common made considerable use in the 1870’s of silvered glass mirrors made by George Calver. About 1892-97 Common himself made, but never finished, a 60-inch mirror. It was later refigured and is still in use.
On these matters see King, op. cit. (footnote 6).
[11] For a list of these, see appendix, p. 184.
[12] Words crossed out in manuscript. See figure 1.