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sink. The usual methods then recommended for the recovery of silver residues did not appear to make any allowance for waste plates, and the practice advocated of boiling the waste emulsion with the acids left in pyroxyline manufacture or with sulphuric acid was not one I cared to adopt. The plan I pursued then and have followed since with success is briefly as follows, and the operations are all such as you are familiar with : —Supposing that you have a pint or so of fogged or defective emulsion ; melt this, and pour into one or two shallow porcelain dishes. Allow it to set, and then pour on a solution of hyposulphite of soda (four ounces to the pint), sufficient to cover. In a short time the film, previously opaque, will be found quite clear and transparent; the film has become, in fact, what photographers call « fixed.” The hypo, solution has dissolved out all the bromide, iodide, or chloride of silver in the* emulsion. The wate plates are treated much in the same way. I have a box capable of holding about two dozen plates. I fill it, and pour on sufficient hypo solution to cover. Very soon the plates are all quite clear, and they may then be re moved and cleaned ; if not allowed to dry, they will be cleaned very easily. It is quite unnecessary to throw away any particle of emulsion or any piece of coated glass or paper. All articles, such as bottles, dishes, funnels, &c.. used in the process of manipulation, are easily and rapidly cleaned with warm hypo solution, and I can say that if done soon after use, the effect is magical. Any amateur who makes his own plates will know and appreciate the value of all this. All these hypo solutions and washings are mixed together in a large bottle, and a sufficient quantity of a solution of ammonium sulphide or potassium sulphide is added to cause the whole to smell strongly : precipitation of the silver as sulphide pro ceeds at once, and when quite set tled at the bottom of the vessel, the supernatant fluid may be poured off, but not necessarily thrown away. The remaining thick liquid should be poured into a filter, the precipitate drained, washed, and dried, and it may now be mixed with half its weight of carbonate of soda and fused in a crucible. If sufficient heat be applied, a button of silver will be the result; if not, the silver will be found as oxide contaminated with soda. The brownish-coloured mass may be powdered, washed with water to free it from soda salt, and dissolved in dilute nitric acid. This solution is boiled to get rid of excess of acid, and then allowed to cool and crystallise. Personally, I prefer to keep the nitrate of silver in solution, test with the argentometer for strength, then convert into bromide with ammonium bromide, and emulsify, It has been suggested to me that the gelatine recovered from the waste emulsion is not worth saving. I do not agree with this. If properly treated I see no reason why, provided the sample be a good one, it may not be used for a fresh batch ; if not, there are other uses to which it could be put. Those who may object to a few even simple operations may keep their silver waste as sulphide until they have sufficient to send to a refiner. In any case I consider, as matters are, the waste of even a single plate inexcusable. Other solutions used in the various processes of our art are also worth saving. For instance, the waste pyrogallic developer, to which a small quantity of saturated sulphate of iron solution has been added, makes a capital writing ink, as the fact that this paper is written with such ink proves. It may be a little thin, but that is a fault easily remedied. — Coxrespondence. STANDARD OF SENSITIVENESS. Sir,—In your impression of the 11th, a letter appears signed “J. D. England,” in which he says he sends out his gelatine plates, marking the sensitiveness by Warnerke’s scale relative to a wet plate. I am at a loss to understand why wet plates should be taken as a standard. I have heard Mr. Warnerke say that with some wet plates he could not obtain a register at all, while in another case he obtained 10 on his sensitometer. I think it is high time to drop the wet plate standard. I am one of the few who can make comparisons (or speed and quality, as I have not discarded the bath.—Yours respectfully, A, L. HENDERSON. Aroceedings f Surieties. NEWCASTLE-OX-TYXE and Northern Counties’ Photographic Association. The ordinary monthly meeting was held on the 8th instant, in the College of Physical Science, Newcastle-on-Tyne, Colonel SHEPPEE in the chair. The minutes of the previous meeting having been read and passed, Messrs. E. B. Mounsey and James Edwards were elected members. The Secretary read a report from the Council, as follows — “ Special Council meeting, held on Thursday, the 27th April, in the County Hotel, Newcastle, at 7.15 p.m.—present, Mr. Payne (in the chair), Messrs. Downey, Dodds, Laws, and Pike—to consider the questions of out-door meetings and the exhibition. The Secretary proposed that there be four out-door meetings, held on the second Tuesday in each month, with the exception of August, in the ordinary way. This proposal met .with general approval, and, after discussion, it was resolved to suggest as places of meeting respectively, Marsden, Chollerford, Riding Mill, and Durham. It was unanimously resolved, subject to the approval of the Association, that an exhibition be held this year in the autumn, and that a sub-committee be appointed at the next general meeting to arrange all particulars. Mr. Payne suggested, with reference to such proposed exhibition, that a silver medal be given for the best set of three seascapes or landscapes, restricted to members of the Association, a bronze medal for the second, and three certificates of honour ; a gold medal for open competition for the best picture on exhibi tion, and a bronze medal for the second ; a silver medal for the best figure study, open competition, and a bronze medal for the second.” A discussion followed as to the out-door meetings, and it was finally decided thas four be held on the third Wednesday in June, July, August, and September, the places being selected as above. With regard to the exhibition : Mr. Auty proposed and Mr. Gibson seconded that a medal be given for the best picture taken at one or other of the out-door meetings. This, on being put to the meeting, was carried. Mr. Dodds authorised the Secietary to announce that a medal would be provided for this purpose. Mr. LYDDELI Sawyer read a paper on “ Sociability in Photo graphic Meetings ” (see page 309). The Secretary read a paper on “A Simple Method of Recovering Silver from Waste Gelatine Emulsion Plates or Paper’’ (seepage 317). Remarks were offered by the Chairman, Mr. Downey, Mr. Sawyer, and Mr. Dodds, to which the Secretary replied. Mr. Lyddell Sawyer then read a paper on “ The Relative Action of Carbonate of Ammonia in Conjunction with Pyrogallol Developers ” (see page 316). A conversation took place in which Mr. Galloway and the Chairman took part. The Chairman proposed and Mr. Readhead seconded a vote of thanks to Mr. L. Sawyer and Mr. Pike, which was carried. A very fine photograph was presented by Messrs. Mawson and Swan, others by Mr. Campbell Swinton and Mr. Templeton, and thanks were duly given to these gentlemen. The following members were nominated and appointed to serve on the sub-committee :—The President, Prof. Herschel, Prof. Bedson, Messrs. Gibson, Laws, Sawyer, Downey, Dodds, J. W. Robinson, Schumann, and the Secretary, with power to add to their number. The meeting was then adjourned. London and Provincial Photocraphic Association. At the meeting held on the 10th inst., Mr. Golding in the chair, Mr. Cowan exhibited a model of a shutter to work at the back of the camera immediately in front of the plate ; the shutter was devised with a view to give the foreground double the exposure received by the sky, and opened from and closed to the top of the camera; the shutter slided down and up in a frame by means of a crank working in a horizontal cut in the shutter, and was released by a spring. Messrs. Wellington and Neate showed a very rapid shutter devised by themselves. The Chairman said that in using a drop shutter if a + was