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 to produce carbon prints by means of photography. The earliest examples exhibited were shown at the April meeting of the London Photographic Society, in 1858: but the author declined to describe the process. An allusion to it and its results, without details, had appeared in one of the journals a few weeks earlier, viz:

MM. Henri Gamier and Alphonse Salmon, in August, 1858, laid before the French Photographic Society, a “Method of Carbon Printing,” in which paper was treated with a strong solution of citrate of iron, and after drying in the dark, was exposed under a transparent positive. The parts acted upon by light were rendered insoluble, whilst the parts protected by the dense portions of the cliché remained soluble and hygroscopic; and