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104 THE PHOTOGRAPHIC NEWS. [FEBRUARY 16, 1883. their destination. Mr. 0. Kay Woods, who assisted Dr. Schuster in Egypt, last year, is to have the responsi bility of the photographic operations, and, let us hope, will receive the honour and glory as well, if the expedition turns out successfully. Mr. Woods travels in company with Mr. H. A. Lawrence, who has been entrusted with the telescopic work. Mr. C. Ray Woods sails from England to-morrow on his courageous enterprise—for it is no light matter to undertake a 200 days’ voyage—out and home —for the pur pose of securing a series of photographs. We are happy in being able to place before our readers a brief account he has written for us, at the last moment, of his preparations, and the nature of his duties. M. Janssen, the well known French astronomer, takes charge of the French Eclipse Expedition, which proceeds to the Pacific. Mr. Woodbury received the silver progress medal of the Photographic Society on Tuesday evening from the hands of the President, who made some interesting rem arks upon the value of the new process, Stannotype. The fact that this latest modification of Woodburytype does away with the use of an expensive hydraulic press is of itself of the highest importance, and, indeed, few photographers under stand how simply permanent impressions can be produced by the method. It is said that if but fifty copies of a negative be desired, it pays to print them by the Stanno type process. The President remarked the other night that it is just twenty-nine years since Mr. Woodbury received his first medal for photography, viz., at Melbourne in 1854. Mr. J. T. Taylor, writing in the Photographic Times, speaks well of a magnesium deflagrating mixture as a means of producing an actinic light. Here are the pro portions :— Chlorate of potash 8 parts Sulphide of antimony 4 ,, Sulphur 2 „ Magnesium dust 2 ,, This matter is of special interest just now, as we find that, although magnesium retains its old price of 12s. per ounce, the dust is quoted in Burgoyne’s recent list at one- third of this price. Mr. Taylor says“ A small portion of this emits, when burned, a flash not only of intense brilliancy, but of ex ceedingly short duration. An engraving that was in a state of motion during the burning of a quantity so small that could be piled on a twenty-five cent piece (say a shilling) yielded a negative (wet plate) which was found on deve lopment to be quite sharp and fully exposed.” The application of the electric light to microscopes was practically illustrated at the last meeting of the Royal Microscopical Society. Minute Swan incandescent lamps specially designed for microscopical examination were used. The carbon loop was enclosed in a very small exhausted pear-shaped glass receiver, the size of a small filbert, so that the light could be b-nught quite close to an opaque object. It was stated that a battery of five Bunsen cells could be used, or two or three small accumulators, an accumulator weighing only five pounds being sufficient to light one lamp continuously for two hours. In the course of the discussion, Mr. Beck raised a point which, if substantiated, would militate somewhat against the use of accumulators. The popular notion of the accu mulator is that when the electricity is exhausted, it is only necessary to re-charge the accumulator, when all would go on as before. This, however, does not seem to be the case. According to Mr. Beck, the Faure Company find they cannot get the same amount of work out of the accu mulators after they had been used some time, so that if at the first charging they would yield 80 per cent, of the energy put into them, they afterwards only give out 40 per cent. If this be the case, a point of zero must ulti mately be reached when the accumulator would be useless. It would be well if this matter were satisfactorily settled, or those who depend upon an accumulator as the source of supply may find themselves wofully deceived. Punch, this week, suggests that Mr. W. B. Woodbury’s invention, “ Photo-filigrane,” may prove extremely useful in the case of visitors’ cards, as, on holding the card up to the light, a portrait is plainly visible; and if the original be a bore or a dun, the answer can at once be given. “ Not at home.” This pre-supposes that the card bears no name or address, an omission which, we fancy, is scarcely contem plated. Those who are not familiar with “ Photo-filigrane” may like to know that it is a method of producing the effects of water-marking in the body of ordinary paper, by pressing it between specially lard rollers. These rollers are engraved by photographic means, and the pictorial effect is caused by the portions of the paper which are com pressed by the design being rendered more transparent to transmitted light, and darker in colour by reflected light. The process promises to be very valuable in connection with the production of designs on bills of exchange, cheques, &c M. Janssen has been sojourning in Oran, and availed hims:lf of the opportunity of an African atmosphere to study the mirage. He was successful in photographing it on several occasions, the result being that he attributes this most romantic of phenomena to causes very different to those usually put forward. He communicates to the French Academy of Sciences the issue of his observa tions. Mr. J. V. Elsden, B.Sc., is engaged in an interesting investigation with the haloid salts of silver in gelatine emulsion, preparing sensitive films in which the iodide, chloride, and bromide are alone and combined, and developing these with solutions of various kinds. “ I think