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watch the camera for a long period, and guard against i gusts of wind and other accidents, I have now to watch it : for barely a minute or so. Portraits were now easily : taken in moderate daylight. One of the first portraits i taken was sent to the French Academy of Sciences, where it excited great interest, and was passed from hand to hand, and afterwards to the public in the galleries, my friend, M. Biot, being my informant. “ I soon drew up an account of this new process, which I named the calotype, and transmitted it to the Royal Society.” The memoir in question was read at the Royal Society meeting of 10th June, 1841, its title being “ An Account of Some Recent Improvements in Photography.” The process, briefly stated, consisted in forming silver iodide, in the first instance, on the surface of paper, sensitising thereafter by means of gallo-nitrate of silver, developing the image after exposure by further applications of the gallo-nitrate solution. The fixing was effected by means of a soluble bromide. The process was patented in Feb ruary, 1841, but in 1852 Talbot, with certain reservations, gave the right to work it to his countrymen. Specimens of early calotypes I have here with me, and can be inspected afterwards. The Calotype, or Talbotype, was a negative picture, the positive reproduction of which was obtained by means of his photogenic paper. By a modi fication of his process, Talbot worked out a method whereby positives were secured in the camera. The modus operandi was as follows : Sensitised calotype paper was exposed to sunlight till a visible browning took place ; afterwards it was dipped into a solution of potassium iodide (25 grs. to oz.), washed in water, dried with blotting- paper, and a good full exposure given in the camera. Development by means of the gallo-nitrate solution was then resorted to, when a positive reproduction was ob tained. I pass a camera picture round secured by this method. In 1842 the Rumford gold medal was awarded Talbot in recognition of his photographic discoveries. At the Cork meeting of the British Association in 1843, Talbot was asked by the general committee “for his reporton photography and its applications to be presented, if pos sible, at the next meeting.” The report asked for does not appear, but we find a communication from Talbot detailing his experiments on sulphate of iron as a deve loper in his calotype process. As is well known, the proposal to use ferrous sulphate emanated from Robert Hunt. The short abstract of Talbot’s paper will be found at p. 105 of Report of Transactions of British Association for 1844. In 1843 Talbot was over in Paris for some little time giving lectures and demonstrating his process. In 1844 the first part of the famous “ Pencil of Nature ” made its appearance. Its publication extended over a period of two years, several unforeseen difficulties having been met with. There were six parts in all, and twenty calotype illustrations in the complete work. In 1845 another work was published having similar photographic illustrations, with the title of “ Sun Pictures in Scotland.” Both works are here for inspection of those interested. In 1846, in the Art Union number for June 1st, an article entitled “The Talbotype Sun Pictures,” evidently inspired by Talbot, forms the first contribution. As a supplement a calotype was furnished with each number. There must be still extant a goodly number of these pictures hidden away in old bookstalls and in libraries. The original issue was something like 7,000, and a large number of negatives seem to have been employed. In all those reproductions which I have seen I have not yet met with a duplicate. I have with me for inspection two of these early Talbotype s. In June, 1851, a remarkable experiment was performed by Talbot at the Royal Institution. A printed paper was attached to a wheel, which was made to revolve rapidly in the dark. On illuminating the paper for a very brief interval of time by means of the electric spark, a photo graphic transcript of the printed matter was obtained on a plate prepared by a method described in the AtJienreum of December 6th, 1851. The process was patented by Talbot. In 1852 Talbot secured a patent for photo-engraving. He gave the name of photoglyphy to his method, and made use of the well-known action of light on bichromated gelatine, the etching of the plate being performed by means of iron perchloride. A subsequent patent was taken out in 1858, the improvement consisting in the application of a resin to the plate before commencing etch ing operations. A supplemental illustration of this mode of engraving was issued with No. 10 of the PHOTOGRAPMIC News, appearing November 12th, 1858. Several plates were employed to give the necessary number of prints for the circulation of the paper ; we find, therefore, that the subjects depicted are somewhat varied, and they mostly are all Continental. A more perfect illustration appeared with No. 54 of the Photographic News, September 16th, 1859 (Vol. III). In this supplement there was only the one subject chosen, a view of a portion of the Tuileries. The plate which furnished the proofs was copper, and had been steel faced. I regret that I am not in a position to show specimens illustrative of Talbot’s photo-engraving. A specimen of a half-tone engraving appears in a second edition of "Tissandier's Photography” already referred to, as also a specimen of line work. These, as I have the book with me, can be seen. Several other patents con nected with photographic applications were applied for. We need only refer to one taken out in conjunction with Malone for the use of unglazed porcelain instead of glass, and employing an albumen process. Enough has been said to show how very assiduously Talbot must have worked at the various photographic methods he from time to time brought forward, but other scientific matters engaged his attention as well. It would be beyond the limits of this communication to enter into these. We are only more immediately concerned with the facts which we have just glanced at. I regret that the marshalling of these had not fallen into the hands of one more capable of rendering full justice to them. It will be our privilege, as a Convention, to visit the shrine of Lacock Abbey, where the illustrious Talbot worked, and surely that “building which was the first that was ever known to have drawn its own shadow,” to use Tal bot’s own expression, must have an interest and significance to the photographic pilgrim which to the ordinary visitor will be completely wanting. Reducing Over-Dense Negatives.—Belizki recommends the following formula. It must be mixed in the order given :— Water 200 parts Potassium ferric oxalate ... ... ... 10 , Sodium sulphite (neutral) 8 ,, Oxalic acid ... ... ... ... 3 ,, Sodium hyposulphite 50 „ It will retain its working strength if kept in the dark, and may be used over and over so long as it has a green colour.
