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THE PHOTOGRAPHIC NEWS. Vol. XXVII. No. 1270.—January 5, 1883. CONTENTS. PAGE The New Year 1 Bichromate Stains on the Hands 2 Precipitation Emulsion Methods 2 Glass 3 By-the-Bye.—-Poisonous Chemicals 4 Transparencies. By J. Hedley Robinson and Dr. Williamson 5 Green Fog a Silver Compound. By A. Haddon 7 Notes ... 8 PAGE Patent Intelligence A Mechanical Aid in Developing. By H. Manners Photographing the Corona. Dark Slides and Multiplying Boxes Correspondence Proceedings of Societies Talk in the Studio To Correspondents 10 11 11 12 14 15 15 16 THE NEW YEAR. Increased activity in most departments of photographic work has characterised the past year; the number of those now engaged in photographic work being consider ably larger than this time last year, and we may fairly ex pect that the interest manifested in photographic matters will show no signs of diminution during the present year. Not only has a large amount of practical experience been gained and the results recorded, but several notable and definite steps iu advance have been made, one of the most important of these being Mr. Plener’s method of isolating the sensitive constituent of emulsion by the agency of centrifugal force. This method, which consists of enclosing emulsion in a kind of metal top so as to drive the suspended particles of silver compound to the sides, and cause them to agglomerate into a hard cheese-like mass, is of especial value, as affording a means of getting rid of all traces of deterio rated gelatine ; there being but little doubt that green fog and many other evils which trouble emulsion workers are solely due to the presence of partially decomposed colloid bodies. Burton’s method of isolating the sensitive com pound by repeated subsidence and washing will prove more convenient to the general worker, as no special ap pliances are required ; but as a manufacturing operation, Plener’s method will undoubtedly be much preferable to Burton’s, and we may picture the advantages which would result from the introduction into commerce of the sensitive compound ; admixture with a warm gelatinous solution being alone necessary to make the emulsion. Quite towards the close of the year a decided step in advance was made as regards the application of photography to physiological research, some admirable photographs of the vocal organs having resulted from the joint labours of Mr. Behnke, Mr. Lennox Browne, Mr. Cadet, and Mr. H. T. Wood. The exposures were made by the light of two powerful arc-electric lights, at the laboratory of the Society of Arts ; two globes filled with a ten per cent, solution of alum serving the double purpose of condensers and cooling cells. Contrary to the expectation of some of the gentle men who were present, a very even illumination was realised by the use of this simple contrivance. Mr. H. T. Wood used a rapid symmetrical with full aperture, and found that an exposure of one second served to give a picture with full details in the shaded parts ; while Mr. Cadett, who made use of a portrait lens, proved a small fraction of a second to be sufficient to impress the sensitive plate sufficiently ; but after some further trials he concluded that it would be better to make use of a slower lens, in order to secure a more considerable depth of focus. The experiments on the occasion referred to only went so far as to produce images of the soft palate in the pro ¬ duction of different tones, a point that had never yet been taken up by any vocal physiologist. Some attempts made a few weeks previously by the aid of the lime light had not been successful, owing to the fact of the illumination being insufficient to overcome the non-actinic character of the mucous membrane; but this difficulty was quite obviated when the electric light was used. Some of the pictures obtained show the soft palate as seen in the production of the F on the fourth line of the bass clef, and the configuration of the parts was illustrated with complete sharpness and detail, every point of light from moisture or follicular prominence clearly coming out. The work of last Friday is exceedingly interesting, because it proves that there will not be the least loss of sharpness as a consequence of movement resulting from the act of singing ; we refer, of course, to muscular move ment of the soft palate, and not to vibratory movement of the vocal organs. When these series are completed it is the intention of the above-mentioned gentlemen to extend their experi ments to the delineation of the vocal ligaments as reflected in the laryngeal mirror during tone-production. Berkeley’s proposal to add sulphite of soda to the deve loper has been much discussed during the past year, and although the main advantages of the system are generally recognized, there are many who fail to obtain uniformly satisfactory results with the sulphite developer ; but it is extremely probable that nothing more than a little further knowledge as to the conditions under which disturbing in fluences step in is required in order to make the advantages of the sulphite method fully recognised. The increased interest manifested as regards photo graphic work generally has been indicated by the establish ment of several new photographic societies, and by the organisation of an exhibition of photographic appliances in connection with the Society of Arts ; while increased in terest has been taken in the doings of the old photographic societies. Some notable advance has been made in photo-mecha nical printing processes, the stannotype process having been considerably improved, while Ives' photo-block method and Sprague’s photo-ink process have been placed on a commercial basis, and have served to illustrate the PHOTOGRAPHIC News and other publications. Details as to the numerous improvements in the practical carrying out of existing methods will be found fully treated of in the Year-Book. During the present year we may look for numerous new applications of photography, resulting from the extreme sensitiveness of gelatino-bromide emulsion ; and should mechanical or other printing methods be notably improved during the year, we may even see daily newspapers illus trated by photographic means.