Hassler was born in Aarau, Switzerland. He was employed on the trigonometrical survey of Switzerland before he emigrated to the United States in 1805. He was acting professor of mathematics at West Point from 1807 to 1810. He was employed by the federal government of the United States by 1811 in an effort to begin a Coast Survey. An Act of Congress on February 10, 1807 had appropriated $50,000 to pay for the beginning of the work. Afterward, he became the first superintendent of the United States Coast Survey in 1816. Two years later, the United States Congress passed the control of the Coast Survey to the army, principally, where it lingered until 1832. Hassler became the head of the Bureau of Weights and Measures in the Treasury Department where he carried out the early work of establishing the standards of weights and measures in the United States, with the involvement of fellow Swiss immigrant Albert Gallatin, who in 1827 brought from Europe a troy pound of brass which was made the standard of mass in 1828. Besides several textbooks of science, Hassler produced a publication in 1828 titled System of the Universe in two volumes. Hassler undertook a complete investigation of the national standards in 1830. Perhaps the most meaningful national standard to be adopted in 1830 was the gallon at 231 cubic inches. In the United States, however, each State retained the rights to employ its own set of standards of weights and measures. Since 1830, a great deal of national legislation has been enacted, with much of it addressing the acceptance or the rejection of the metric system. The United States Bureau of Standards was created by an Act of Congress on March 3, 1901. As mentioned above, the Coast Survey languished for 14 years from 1818 to 1832. In 1823, 1824, and 1825, the Navy Department tried to establish a hydrographic office. Also, the Survey was a source of discussions in Congress, which finally passed a law on July 10, 1832 that resulted in the removal of the Survey away from the army and the navy. Hassler was appointed the superintendent of the Survey on August 9, 1832, and he served in that post until his death on November 20, 1843. The steamship owned by the Coast Survey was named the Hassler. "The unit of length to which all distances measured in the Coast Survey are referred is the French metre, an authentic copy of which is preserved in the archives of the Coast Survey Office. It is the property of the American Philosophical Society, to whom it was presented by Mr. Hassler, who had received it from Tralles, a member of the French Committee charged with the construction of the standard metre by comparison with the toise, which had served as unit of length in the measurement of the meridional arcs in France and Peru. It possesses all the authenticity of any original metre extant, bearing not only the stamp of the Committee, but also the original mark by which it was distiguished from the other bars during the operation of standarding. It is always designated as the Committee metre". Ferdinand Rudolph Hassler's granddaughter, Mary Caroline Hassler Newcomb, married the much noted astronomer and mathematician Simon Newcomb. Simon and Mary Caroline Hassler Newcomb were themselves the grandparents of the also much noted professor of mathematics, Hassler Whitney. He died on November 20, 1843 and was interred in Laurel Hill Cemetery in Philadelphia.
