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November 16, 1883.] THE PHOTOGRAPHIC NEWS. 729 with the instruction which is given in photography at some of the centres in connection with the City and Guilds of London Institute. Some drawings were sent to the paper inquestion by an individual living in one of the Midland towns. Accompanying the drawings was a card setting forth : “ City and Guilds of London Insti tute (Gresham College), Examination in Photography. Bronze medal and first-class certificate, 1881. Full cer tificate granted March, 1881, awarded to .” The drawings were partly in pen-and-ink, and partly in Indian ink, the use of the latter, applied, as it was, with a brush, rendering them totally unfit for reproduction in photo graphy, for which they were intended. The sender could not have had the least notion of the requirements of photography so far as copying was concerned, and yet he had carried off a bronze medal and two certificates! The details of the process for obtaining bichromate of soda, for which Messrs. Potter and Higgin, of Bolton, have obtained a patent, have been published. Up to the pre sent bichromate of soda has been unknown as a commer cial salt, but if the new process be successful, it should be in great demand, as it is a more powerful oxidizer than bichromate of potash. It remains to be seen how it will act in combination with gelatine for photographic pur poses. The patentees claim that it can be produced at a less cost than bichromate of potash. M. Leon Vidal’s electric photometer, in which the con ductivity of selenium, altered by light, is made to register changes in illumination, is already well-known to our readers. Another electric photometer, brought forward by Herr Sauer, secures the same end, but by very differ ent means. Herr Sauer’s instrument is, in fact, a battery, that acts only in the sunlight, and according to the ^lectrolechnische Zeitschrift, it will at once move the needle of a galvanometer if a fleecy cloud obscures the sun for a few moments. The action of the battery depends on the effect of chloride of copper upon mercury; subchloride is formed, and reduces the chloride of silver in the battery, such change, however, only taking place under the action of sunlight. The battery is easily described. It consists of a glass vessel containing a solution of 15 parts of common salt, and 7 parts of sulphate of copper in 106 parts of water; in the glass is placed a porous cell containing mercury. One pole or electrode of the battery is of platinum wire, and this is immersed in the mercury ; the other pole is of sulphide of silver, and is placed in the salt solution. When the battery is placed in sunlight, an electric current is set up, which will at once move a galvanometer needle. “ Say I am a photographer with a new process so; sensi tive it can only be worked at midnight,” is the excuse suggested in the Silver King by a chevalier de I'industrie who meditates a quiet burglary. The general public consider the joke a very good one, for they have heard a good deal about new sensitive processes lately. Medals, disappointing as they are to the non-receivers, . do not always bring satisfaction to the recipients. The case of Mr. G. F. Williams, who won the gold medal at the Alexandra Palace competition, but found there was no medal to take when the time came to take it, the honours attaching thereto having in like manner been absorbed by somebody else, whose name was printed in lieu of that of Mr. Williams—such a case, we say, may not happen every day ; but many medallists find their awards con siderably discounted on receipt. Thus, to receive a bronze medal, say of the value of tenpence, and to pay a sum of thirty shillings or two pounds for expenses, is not an unusual experience nowadays, although the most striking instance of the kind we know is Mr. Woodbury’s award at the last Moscow Exhibition. Here, no less an honour than the gold medal fell to bis lot; and this, he was informed, would be at once forwarded to him from the ancient capital of Russia on receipt of twenty-eight pounds! A funny story, by-the-way, is told of the recent Amsterdam Exhibition. A soap-maker, who makes it a custom to exhibit at these international gatherings, was awarded by the Dutch authorities nothing more than an honourable mention. The irate manufacturer of saponified tallow simply wrote back that he wouldn’t take it; he was used to getting medals at these exhibitions, and by St. Chiistopher !—or, whoever the god of soap may be—a medal he would have now. The Exhibition authorities apologized, acceded to his request, and the matter ended. The German photographic societies have, of late, made considerable progress in the enrolment of members, the number of which compare favourably with those in Great Britain; only, in quoting figures, it must be remembered that our population and that of Germany are widely diffe rent. The most popular society among our German- speaking brethren is that at Vienna, which counts 376 members. In the Fatherland, the German Photographic Society, with its head-quarters at Weimar, claims 333, but then Berlin has two big societies, that for the Advancement of Photography mustering 308, and the Berlin Photographic Society with 179. Then there is an " International Victoria ” Society, holding its meetings at Guben, with 101 members, the Frankfort Society with 90, the Munich Society with 50, the Rhinish- Westphalian Society with 43, the Schleswig-Holstein with 39, the Hamburg Society with 29, and the Nurnberg Society with 20 members. Our readers may like to know how much German mem bers pay on account of annual subscription to their societies. ' We shall be happy to inform them, only here, again, it must be remembered, there is a difference in the value of money between us and our German-speaking cousins. To the . Vienna Society, the annual subscription is eight florins i (say 13s 6d.); to the Society for the Advancement of > Photography in Berlin, it is sixteen marks, or shillings; r and to the other Berlin Society, twelve marks. In the 1 German Society, and those at Munich, Hamburg, Frankfort, Westphalia, the subscription is ten marks, and in Nurnberg,