1860-70] ROYAL ASTRONOMICAL SOCIETY 159 theorique." Delaunay confirmed Adams's value of the accelera- tion attributable to secular variation of the eccentricity of the earth's orbit, and assigned the outstanding discrepancy between observation and calculation to the existence of another source of variation, namely, the secular lengthening of the day by the action of tidal friction. Adams had the great satisfaction not only of the recognition of his own labours, but also of doing honour to Delaunay, when in 1870 he delivered the address on presenting the Gold Medal of the Society to him. The Rev. Charles Pritchard [1808-93] was elected President of our Society in 1866. He had entered St. John's College, Cam- bridge, in 1826, and was fourth Wrangler in the Mathematical Tripos in 1830. Two years later he was elected to a Fellowship in his college, and in 1834 he became the first headmaster of Clapham Grammar School, founded as a new venture by the leading men in Clapham. The new school, with its eager enthusi- astic master, attracted pupils from all parts of the kingdom, and men distinguished in science and the liberal professions sent their sons to him to benefit by the breadth and originality of his teaching. In 1862 he retired from the headmastership. He had joined our Society in 1849, was elected on the Council in 1856, and served as Secretary from 1862 to 1866. His election to the Savilian Professorship of Astronomy at Oxford, in succession to Professor Donkin, in 1869, was the beginning of a new opportunity, in which he showed untiring zeal and energy. Pritchard delivered two addresses during his Presidency, on presenting the Gold Medal of the Society, first in 1867 to William Huggins [1824-1910], and William Allen Miller [1817-70] con- jointly for their researches in Astronomical Physics, and then in 1868 to Le Verrier for his Planetary Tables. The award of the Gold Medal to two persons conjointly in 1867 involved a suspension of certain of the Bye-laws. The ordinary meeting of the Society in January was followed by a Special General Meeting, at which a resolution was passed empowering the Council " to award the medal to two gentlemen who have been engaged conjointly in a work of astronomical importance." The Council reassembled after the Special General Meeting, and pro- ceeding to the ballot, they awarded the medal to Huggins and Miller conjointly. At the February Meeting the Council resolved that the medal be engraved in duplicate with the names of the two recipients. Little did the President or anyone else at the time think of the revolution that was to come in the next quarter century.
