the prime vertical, and those with the mural circle, it contained various important investigations of the errors and corrections peculiar to the instruments. Prof. Coffin's masterly discussion of the adjustments of the mural circle, and his expansion of Bessel's Refraction Tables, Walker's investigation of the latitude of the observatory, and his comparison of the standard thermometers; all of great value."
In the second volume reference was made to the discovery of Neptune, and the success of Mr. Walker, one of the assistants, in detecting, among Lalande's observations, two of Neptune, on May 8 and 10, 1795, when the planet was observed and recorded as a fixed star. "Astronomers were thus furnished with an observation of Neptune made fifty-two years before, which afforded the means of a most accurate determination of the orbit, and enabled the superintendent of the American Nautical Almanac to publish an ephemeris of the new planet two years in advance of all other parts of the Almanac. The observatory was first brought into prominence by these researches." In October, 1849, Lieutenant (now Rear-Admiral) Davis wrote as follows to the Hon. Secretary of the Navy on this subject: "The theory of Neptune belongs, by right of precedence, to American science. In connection with its neighbor, Uranus, it constitutes an open field of astronomical research, into which the astronomers and mathematicians of the United States have been the first to enter, and to occupy distinguished places." Deprecating heartily though I do, all reference to priority or nationality in such matters as opposed to the true scientific spirit, I cannot but note how Prof. Newcomb, by his admirable researches into the theory of Uranus and Neptune, has fulfilled the hopes thus expressed nearly a quarter of a century before his labors were brought to a successful termination.
The work of the observatory, thus happily inaugurated, was prosecuted steadily till 1861, when Commander Maury left Washington to join the cause of the Confederate States. During the greater part of the war the observatory was under the charge of Captain Gilliss, who died on February 9, 1865. "It has been noted as a strange coincidence of circumstances," says Prof. Nourse, in the memoir of the observatory from which we have been quoting, "that the last morning of his life witnessed an announcement of results deduced at this observatory which had fulfilled his long-deferred hope of determining the solar parallax by simultaneous observations in Chili and in the United States. This announcement would have been peculiarly gratifying to him because these results were from the joint activity of the two observatories, founded through his exertions, 5,000 miles apart."
From 1865 to 1867 the observatory was under the superintendence of Rear-Admiral C. H. Davis, and from 1867 to the present time it has been under that of Rear-Admiral B. F. Sands. Without further considering the work accomplished at the observatory itself, which