Introduction, by R. C. Olby.--Sir Humphry Davy, 1778-1829, by D. Knight.--Jons Jacob Berzelius, 1779-1848, by D. M. Dallas.--Thomas Young, 1773-1829, by J. R. Levene.--Louis Jacques Mande Daguerre, 1789-1851, and William Henry Fox Talbot, 1800-77, by P. R. Norman.--Sir Charles Lyell, 1797-1875, by J. P. Bolam.--Adolphe Quetelet, 1796-1874, by G. M. Jolly and P. Dagnelie