PRACTICAL astronomy in this country has sustained a serious loss in the death of the Rev. Robert Main, which took place at the Radcliffe Observatory, Oxford, on the morning of May 7. Mr. Main entered at Queen's College, Cambridge, and graduated as sixth wrangler in 1834, and was Fellow of his college 1836-38, taking clerical orders in 1836. On the appointment of the present Astronomer-Royal he was selected to fill the office of First Assistant in the Royal Observatory, Greenwich, which position he retained, until, on the death of Mr. Johnson, he was appointed, in June, 1860, to the direction of the Radcliffe Observatory. During his connection with the Royal Observatory he was a frequent contributor to the Memoirs of the Royal Astronomical Society, his first paper “On the Node and Inclination of the Orbit of Venus” having been presented in June, 1837. This was followed by memoirs “Onthe Correction of the Mean Distance, Eccentricity, Epoch, and Longitude of the Aphelion of the Orbit of Venus,” and he returned to the same subject in two subsequent communications read April 13 and December 14, 1838. In May, 1840, Mr. Main contributed a paper on “The Present State of our Knowledge of the Parallax of the Fixed Stars,” which was of much ralue at the time, as presenting a condensed criticism of all that had been effected in this direction; this paper was originally read to the council, in support of Bessel's claim to the gold medal for “his assumed discovery of the parallax of the remarkable star 61 Cygni.” In 1845 Mr. Main procured the reduction of the numerous sextant observations of the great comet of 1843, the results of which were presented in a memoir read m January, 1846; but they did not justify, in point of precision, the time and trouble which had been expended upon them. In a paper read March, 1849, Mr. Main gave his deductions on the ellipticity and form of the planet Saturn, from measures at the Royal Observatory, showing that there is not, as was suspected by Sir William Herschel, any sensible deviation from a perfect ellipse. In April, 1856, he made a communication on “the values of the diameters of the planets having measurable discs,” embodying observations with a double-image micrometer, extending from 1840 to 1852. His subsequent contributions to the same memoirs are (1) “on the Value of the Constant of Refraction”(1857), (2) “On the Proper Motions of the Stars of the Greenwich Catalogue of 1576 Stars for 1850”(1858), (3) “On the Value of the Constant of Aberration”(1860). Mr. Main successively filled the offices of Secretary and President of the Royal Astronomical Society.