While an impulse was thus given to the mathematical theory of light in the University of Cambridge, similar progress was being made in the sister University of Dublin, where three of her most eminent professorsSir William Rowan Hamilton, Dr. Lloyd, and Mr. M'Cullaghdevoted themselves energetically to its improvement and verification. Sir William Hamilton, a geometer of the first order, having undertaken a more complete discussion of the wave surface of Fresnel, to the equation of which he gave a more elegant form, ascertained the exact nature of that surface, and consequently the exact direction of refracted rays in the neighbourhood of the optic axes. The beautiful and unexpected results he obtained were verified by his friend Dr. Lloyd. The names of Sir William R. Hamilton and Dr. Lloyd will be handed down to posterity in connection with this discovery. "But," says Professor Forbes, "they have other claims to our respect. The former has generalised the most complicated cases of common geometrical optics, by a peculiar analysis developed in his essays on 'Systems of Rays.' To Dr. Lloyd we are indebted for several interesting experimental papers on optics, for an impartial review of the progress of the science, and for an excellent elementary treatise on the wave theory."With the beginning of this year, 1769, there commenced, under the signature of "Junius," the most remarkable series of political letters which ever appeared in our political literature. Time has not yet disclosed who this public censor was, though the most weighty reasons attach the belief to its having been Sir Philip Francis. Whoever he was, his terrible dissections of the conduct and characters of public menthe Duke of Grafton, the Duke of Bedford, Lord Mansfield, and others, not excepting the king himselfcaused the most awful consternation amongst the ranks of the Ministry, and raised the highest enthusiasm in the public by the keen and caustic edge of his satire and his censure, by the clear tone of his reasonings, his obvious knowledge of secret Government movements, and the brilliant lustre of his style.
