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2 THE PHOTOGRAPHIC NEWS. [January 2, 1863. landscape during the summer, so absorbing have been the demands of portraiture. Nevertheless, we hope that the forthcoming Exhibition will not be wanting in good examples of landscape photography. Instantaneous photography has excited much attention during the year, and its conditions seem to be better under stood as consisting in simplicity rather than complexity. Good chemicals, good lenses, and good light; bromo- odized collodion, and iron development, are generally known to be the main requisites. Breese’s wondrous in stantaneous transparencies have excited so much admira tion, that he has been induced to appoint London agents for their sale ; and his moonlight pictures, at one time regarded by many as a hoax, are now received as veritable results. Wilson, Blanchard, Kibble, Harman, and others, have all added their quota of instantaneous results during the year, whilst England has not been less usefully engaged in producing many thousands of charming souvenirs the art treasures in the Exhibition. We have had the pleasure of chronicling various minor improvements during the year, which do not need specific mention here. Although there still remains much room for improvement, there has been unquestionable progress in the art aspects of photography. The appliances of photo graphy have been improved, its applications extended, and increased activity generally been manifested. Photographic societies generally have not been progressing. The London societies have, it is true, increased in numbers, and some of the provincial societies have also been.prosperous; but there has been a general declension on the whole, many of the societies having either died, or sunk into a torpor which resembles death. One of the most important and satisfactory events of the year was the passing of the new Copyright Act, which gives to the photographer the sole right to reproduce his own pictures, and checks piracy by the prompt enforcement of penalties. We confidently anticipate, in the coming year, continued progress, and hope for all our readers renewed and increased prosperity; AMMONIA DEVELOPMENT. The recent experiments in ammonia development are likely to suggest many valuable theoretical conclusions, both regarding the nature of the process of development, and the operation of preservative preparations. It is clear, for in stance, from recent experiment, that the use of the coating of tannin is not merely of a mechanical character. It is not simply a varnish helping to render the desiccated film permeable by aqueous solutions, as has been suggested by some authorities. If this were the case, a solution of am monia would be sufficient to develop plates prepared by other methods. We recently tried the effect of ammonia on plate simply washed and dried without preservative. No pererptible result whatever followed ; but on the addition of a little pyrogallic acid to the solution, an image rapidly appeared. The negative was not a satisfactory one, as, on intensifying, fog and irregular deposit ensued. We had not time then to repeat the experiment, only having a single plate at hand. A letter recently received from Mr. Leahy confirms this result, and adds the interesting fact that car bonate of soda answers the same purpose as ammonia. He writes as follows :— Sir,—Since my former communication on the subject of developing by ammonia, I have been trying some experi ments, with the view of finding out whether the develop ment was due solely to the ammonia or to the tannin and ammonia combined. For this purpose I prepared plates by the ordinary tannin, the Fothergill and Sisson’s (borax and gum) processes. The pictures taken on the plates, prepared by either the Fothergill or the borax and gum process, could not be developed by ammonia alone, but were rapidly brought out by a mixture of tannin and ammonia. The proper proportions seem to be, from 10 to 15 drops of strong ammonia to an ounce of the ordinary 15-grain tannin solu tion. The plates prepared by the borax and gum process gave beautiful results, when treated with the foregoing mixture of tannin and ammonia. The pictures were of a reddish brown, and very sharp and vigorous, even before the application of the pyrogallic acid and silver, the principal use of the latter (with pictures, developed by the above( being to intensify, almost all the details being visible before its application. I have also tried a solution of common soda for developing tannin plates, and with almost as much success as the ammonia. A solution of tannin, with the addition of a little soda, will develope either the Fothergill or the borax and gum prepared plates, but rather slowly. The foregoing modes of developing would, I should think, succeed with any of the dry processes, but I have tried them only with those mentioned. The development seems to be owing to some decomposi tion of the tannin, as, in its absence, neither the ammonia or the soda produced any effect.—Your obedient servant, Thomas M. Leahy. Dublin, X&tli December, 1862. In a recent letter, Major Bussell adds some interesting remarks, which we subjoin. He says :— “ With regard to the ammonia development, I have had no failures in the way of working I have described, except in a few of the earliest experiments, before I had found out the proper proportions of ammonia, and the necessity, of thorough washing before intensifying with the ordinary developer. When these points were attended to, there has never been in my hands the slightest tendency to fogging or irregular action. My plates, I may observe, were all thoroughly freed from nitrate, sometimes by immersion in strong solution of salt, and always were soaked for hours in common water. I have found, by careful experiments, that the ordinary mode of development can be made to bring out an image after nearly as short an exposure as the am monia and pyro, by using at first a very strong solution of pyro, with a mere trace of silver and acid; but in cases of short exposure, the ammonia treatment, besides economising the pyro, appears always to have its advantage in brightness and cleanliness. “ You are not satisfied with my idea as to the manner in which the ammonia acts. I put it forward with diffidence, as very little is known on the subject; but if it is not the true one, it, at any rate, seems the most probable explana tion. Ammonia, added to tannin or pyro in solution, causes discolouration of the same kind as is produced by the ad dition of nitrate of silver ; and if this action takes place on an exposed plate, the appearance of the image takes place in a very similar manner, and is of the same colour. The chief difference is, that tannin and ammonia develop much more energetically than tannin and nitrate of silver. “ The difference between the energy of ammonia and nitrate with pyro is not so great; gallic acid with ammonia is intermediate in effect between tannin and pyro, when all are used with ammonia. In Mr. Leahy’s experiments the development was produced by the action of the ammonia on the tannin. Mr. Hurst’s theory that the ammonia only acts in making the developer penetrate cannot be right, as, with the collodion I use, the strongest solution of pyro will pro duce scarcely any trace of an image—usually no perceptible trace, in a quarter of an hour—the liquid containing enough alcohol to make it completely penetrate and whiten the film immediately, whilst the addition of one thirty-second of a drop of ammonia will cause the image to start out in all its details in a few seconds, “ The subject is rather obscure; I do not understand the action of heat with tannin alone ; heat will discolour pyro gallic solution, but I think not tannin.” Regarding the question of development, we differed from so careful an observer as Major Russell with considerable diffidence; but we felt that his view of the theory did not
