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555 compared with pure bromide. The part with iodide is! still further proved by the fact that a film composed entirely invariably slower to appear. The colour of the film | of iodide of silver can be developed to a much greater becomes browner with increase of iodide. The loss in I extent by means of sulpho-pyrogallol than by ferrous- density, and absence of fog, with increase of iodide, is still i oxalate. The great difficulty in fixing films containing more marked in this case than with ether developers. In I much iodide is a point not to be overlooked. In some fact, ferrous-oxalate does not seem to act so readily upon ! cases, where the bromide parts fix in a few minutes, the bromo-iodide films as the pyro developer does. This is iodide parts required three or four hours. Seeing that Comparative View of the Effect of Variation in the Proportion of Chloride in Emulsions. Number of Plate and Nature of Emulsion. Ordinary Pyro Developer. Sulphite Developer. Oxalate Developer. Plate 1— Portion coated with AgBr ... Ditto, AgBr-2 50/AgCl Ditto, AgBr++50/AgCl Over-exposed and thin. ) No difference, except slight > tendency to fog in last divi- ) sion. The lines of division between the separate portions not to be dis tinguished either by reflected or transmitted light. Rather under-developed, other wise good. 1 Shadows veiled ; image weaker } than above portion. The separate portions are scarcely to be distinguished. Image stronger than rest of plate, 1 Tendency to fog; image } weaker than above portion. The separate portions are scarcely to be distinguished. Plate 2— Portion coated with AgBr ... Ditto AgBr+80/AgCl Ditto AgBr-|-10%AgCl ) Rather over-exposed and thin, C but otherwise no difference ( visible anywhere, either by ) reflected or transmitted light. Green fog on shadows only. ) Green fog over whole plate; - on the shadows the fog is ) red. Better than rest of plate ; no fog. | Inferior to above, but differ- $ ence is very slight; no fog. No difference in colour of image. Plate 3— Portion coated with AgBr ... Ditto AgBr-140/AgCl Ditto AgBr-180/AgCl Thin ; clear shadows; distance clear. ) Tendency to fog ; distance in- - distinct; green fog in last ) division. No green fog; dense; good con trast. 1 Green fog; shadows veiled; j image weak. Dense and brilliant. 1 Weaker and less contrast, but j no fog. No difference in colour of image. Plate 4— Portion coated with AgBr ... Ditto AgBr--200/AgCl Ditto AgBr-230/0AgCl Clear shadews ; distance distinct; no fog. Fog in shadows; distance much fogged, especially in last portion ; green fog in the last division. 1 Bad throughout, the whole 1 fogged > but the chloride f parts are visible from greater J weakness of imago. Dense, clear shadows. 1 Image generally weak, with J slight veil over shadows. No difference in colour of image. Plate 5— Portion coated with AgBr ... Ditto AgBr+290/AgCl Ditto AgBr-+33°/AgCl Good, clear distance and shadows 1 Slight fog; distance very in- J distinct, but no green fog. Slight fog; otherwise fair. Ropeless green fog; image J weak; negative bad. Good density ; clear distance. I Shadows fogged; distance in i' distinct. Plate 6— Portion coated with AgBr ... Ditto AgBr-+66°/AgCl Ditto AgBr-f-lOO ,, /oAgCl Good, bright negative. Fogged, without detail or con trast. Much fogged: thoroughly bad in every way. Fairly good. ! Hopeless green fog; tho- ) roughly bad negative. Good, but slight fog. Green fog, and thoroughly use- J less. No difference in colour of image; collodio-iodide films fix readily enough, this requires ex planation. With the exception of the difficulty of fixing, there seems to be considerable latitude in the amount of iodide that may be employed in an emulsion. ing an intermediate week at Eisenach, in Thuringia, which, in my opinion, is even better worth a visit than the grand river itself. Of course I saw the Wartburg, Annathal, Ruhla, Gotha, and some other places mentioned in your “ Beauty Spots of the Continent ”; but, excepting the first, these do not seem as yet to have attracted as much attention as they deserve at the hands of photographers. Jagemann, of Eisenach, has a good Wartburg series, but I saw little artistic work besides in this district. But to the Rhine ; commencing at Cologne, one finds a row of shops in the Dom Kloster, devoted to the sale of whole-sheet prints of the now finished Cathedral, and en largements of its doorways, pinnacles, flying buttresses, and a variety of architectural details ; also general views of town and churches as seen from the river. These large prints are priced six marks each, and are well worth the money; but some of the more ambitious productions, particularly of the Cathedral itself, are open to improve- PHOTOGRAPHY ON THE RHINE. An occasional correspondent, lately returned from a visit to the Rhine and neighbouring parts of Germany, sends us the following. You may perchance be interested in having a report of what is on show at the present time at the chief photographic establishment on the Rhine, and I give you my impressions: premising, however, that I may very possibly have omitted to take note of some things well worth mentioning, but which did not, from the hurried nature of my visit, happen to come under my observation. I went both up and down the Rhine, spend-