Background
George Davidson was born on May 9, 1825 in Nottingham, England. He was the son of Thomas Davidson and Janet Drummond. In 1832 he came to America with his parents, who settled in Pennsylvania.
Astronomer geodesist geographer scientist
George Davidson was born on May 9, 1825 in Nottingham, England. He was the son of Thomas Davidson and Janet Drummond. In 1832 he came to America with his parents, who settled in Pennsylvania.
Davidson graduated first in his class, from the Central High School, Philadelphia, and in 1843 was appointed magnetic observer at Girard College, through the influence of Alexander D. Bache, who had been a member of the High School faculty.
Davidson's service in the United States Coast Survey began in 1845, when he went to Washington as secretary to Superintendent Bache, and ended with his retirement in 1895.
He was sent to California in 1850, at the head of a party entrusted with the task of making an accurate survey of the Pacific Coast to meet the needs of navigation. The rest of his life, with the exception of the years 1860-66, which he spent in the Atlantic Coast service, was passed in the West.
The first requirements of the survey were the determination of the latitudes and longitudes of prominent coast features, and the survey of harbors and harbor surroundings.
Longitudes of principal stations were determined from observations of the moon’s place among the stars and from occultations of stars by the moon; those of secondary stations by the transport of chronometers. Telegraphic communication was at that time not available. Data were so quickly and thoroughly assembled that soon he was able to issue his first “Directory for the Pacific Coast of the United States” for the use of mariners.
Its great value came from the fact that the compiler had become intimately acquainted with all the natural dangers and possibilities of the coast.
In 1866 he was ordered to make a survey of the coast of Alaska.
His official report, first published as an appendix to the report of the superintendent of the Coast Survey was republished in revised and enlarged form as the Coast Pilot of Alaska (1869).
In 1869 telegraphic signals were exchanged between Harvard College Observatory and a temporary observatory in San Francisco and the longitudes of Pacific Coast points placed on an accurate basis.
Davidson’s work in applied astronomy gave him the incentive to contribute also to pure astronomy, and his reports and writings show that he always had this broader aspect of his work in mind. At various stations he observed several partial eclipses of the sun and, more elaborately, two total eclipses and a transit of Mercury.
He was appointed to direct the observations of the transit of Venus, once in Japan (1874) and once in New Mexico (1882). From time to time he published catalogues of star positions. At the San Buena Ventura station, he observed 556 meteors in 1870. At a station in the Sierra Nevada Mountains he tested astronomical conditions and was much impressed by the advantages of a high altitude.
This investigation bore important fruit when Davidson adroitly guided and defined the somewhat vague intention of James Lick to leave money for a great telescope, although the final selection of the site, on Mount Hamilton instead of in the high Sierras, was somewhat of a disappointment to the former. Before the Lick Observatory was built, Davidson had his own private observatory in LaFayette Park, San Francisco. Erected in 1879 and containing a 6. 4-inch Clark telescope, this was the first observatory in California. Here, in 1891-92, he made a long series of observations of latitude pairs as a contribution to the puzzling question of the variation of latitude, and confirmed the results found elsewhere.
While his chief studies were in astronomy, his help and interest were always available in other departments of science.
Davidson was an authority on the early history of the Pacific Coast. He served on the Advisory Harbor Improvement Commission for San Francisco, 1873-76, the Mississippi River Commission, 1888, and the United States Assay Commissions of 1872 and 1884. He was elected a Regent of the University of California, serving in 1877-84, and later was appointed honorary professor of geodesy and astronomy in the University.
It is said that for sixty years his name was more familiar to the scientifically inclined on the Pacific Coast than that of any other resident.
Davidson's personal charm brought him many friends.
In October 1858 he married Ellinor Fountleroy of Virginia.
