The year 1838 gave birth to another photographic discovery, little thought of and of small promise at the time, but out of which have flowed all the various modifications of solar and mechanical carbon printing. This was the discovery of Mr. Mungo Ponton, who first observed and announced the effects of the sun's rays upon bichromate of potash. But that gentleman was unwise in his generation, and did not patent his discovery, so a whole host of patent locusts fell upon the field of research in after years, and quickly seized the manna he had left, to spread on their own bread. Mr. Mungo Ponton spread a solution of bichromate of potash upon paper, submitted it under a suitable object to the sun's rays, and told all the world, without charge, that the light hardened the bichromate to the extent of its action, and that the unacted-upon portions could be dissolved away, leaving the object _white_ upon a yellow or orange ground. Other experimenters played variations on Mr. Ponton's bichromate scale, and amongst the performers were M. E. Becquerel, of France, and our own distinguished countryman, Mr. Robert Hunt. During the years that elapsed between the death of M. Niépce and the period to which I have brought these records, little was heard or known of the researches of M. Daguerre, but he was not idle, nor had he abandoned his iodine ideas. He steadily pursued his subject, and worked with a continuity that gained him the unenviable reputation of a lunatic. His persistency created doubts of his sanity, but he toiled on _solus_, confident that he was not in pursuit of an impossibility, and sanguine of success. That success came, hastened by lucky chance, and early in January, 1839, M. Daguerre announced the interesting and important fact that the problem was solved. Pictures in the camera-obscura could be, not only seen, but caught and retained. M. Daguerre had laboured, sought, and found, and the bare announcement of his wonderful discovery electrified the world of science. The electric telegraph could not then flash the fascinating intelligence from Paris to London, but the news travelled fast, nevertheless, and the unexpected report of M. Daguerre's triumph hurried Mr. Talbot forward with a similar statement of success. Mr. Talbot declared his triumph on the 31st of January, 1839, and published in the following month the details of a process which was little, if any, in advance of that already known.