CLAUDET, Antoine François (1797-1867), an eminent photographer, was born at Lyons. Shortly after the publication of Daguerre’s results (1839), Claudet, by the addition of bromide and chloride of iodine to the iodide of silver employed by the former discoverer, greatly accelerated the process of production. This, with the use of iodide of gold in fixing the image, may be said to have completed the invention. In 1848 Claudet produced the photographometer, an instrument designed to measure the intensity of photogenic rays; and in 1849 he brought out the focimeter, for securing a perfect focus in photographic portraiture. In 1850 he received a medal from the Society of Arts and Manufactures for a machine to cut glass of any curvature of surface. This was followed in 1851, 1855, and 1862 by the medals awarded by the French and English universal exhibitions for eminence in and discoveries connected with his profession, and in 1853 by his election into the Royal Society. In 1858 he produced the stereomonoscope, in reply to a challenge from Sir David Brewster. Claudet, who was photographer in ordinary to Her Majesty, was also a décoré of the Legion of Honour, and had received tokens of admiration and regard from Louis Philippe and the Czar Nicholas.