Lectures on the Wave-Theory of Light.

Dublin: Andrew Milliken 1841, 1841. Presentation copy from author to the Earl of Rosse. First edition. 8vo. 222x140mm. pp. i-iv, 5-89 [1]; 83 [1]. Two folding engraved plates. Original green cloth, paper label to spine. Staining to covers, spine faded, corners bumped. Internally very good. A nice copy of an important book creating an interesting link between two leading Irish scientists of the nineteenth century. The first part is a reprint of the six lectures given by Lloyd on unpolarized light in 1836 while the second part (on polarized light) appears for the first time. Rare in commerce. Humphrey Lloyd (1800-1881) was the professor of Natural and Experimental Philosophy at Trinity College Dublin and was one of the leading proponents of the wave-theory of light - the idea that light is formed from vibrating waves rather than particles which was the Newtonian theory. This change was brought about in large part through a revolution in scientific methodology. William Parsons, the 3rd Earl of Rosse (1800-1867) was president of the Royal Society, a builder of giant telescopes including the world's largest at his home, Birr Castle in County Offaly. His most significant work was in astronomy. Lloyd and Rosse would have known each other as students at Trinity and must have remained in contact throughout their lives. Both were members of the British Science Association and Rosse became the Chancellor of TCD during Lloyd's period as a senior Fellow. This book is a touching testament to an intellectual bond.