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Show o PHOTOGRAPHS BY WIRE. A complete description of Professor Korn's apparatus for the transmission of photographs by wire, which has already been noticed in the columns of the Literary Digest, is contributed by Max dc Nansouty to La Nature ( Paris.) The writer heads his article "Telephotography" an unfortunate word, since it is already in use to denote de-note long -distance photog r a p h y through telescopic lenses. He is very enthusiastic about Korn's invention, and believes that it heralds the near approach of long-distance vision "seeing by tclcgraph"--in which pcr-. pcr-. haps other experts will hesitate to follow him. After a detailed description descrip-tion of previous attempts along this line, which have met with greater or less success, Mr. Nansouty goes on to describe Professor Korn's device as follows: "At the transmitting station is a glass cylinder turning on its axis and rising vertically, so that its surface lias a screw motion. This is enclosed en-closed in a cylindrical dark chamber with the same axis, having a small opening through which a Nernst electric elec-tric lamp casts a ray of light. The photographic film to be reproduced is rolled on the glass cylinder. "Inside this cylinder is a reflection prism that sends the rays of the lamp vertically toward the base of the cylinder, cyl-inder, after they have traversed the different points of the photographic film. Each of these rays has undergone under-gone a diminution of intensity depending de-pending on the capacity of the photograph pho-tograph at the point through which it passed. "These refracted rays fall on a plate of selenium placed at the base of the cylinder and interposed in the circuit of an electric battery. "It is well known that selenium has the property pf conducting the electric elec-tric current when struck by a light-ray light-ray or a luminous ibration; it behaves be-haves toward light-waves as a 'coherer' 'coher-er' does toward electric waves in wireless telegraphy. Its conductivity depends on the intensity of the waves that fall upon it. Thus the selenium plate sends out over the line that ! connects the two Korn stations a scr- H ics of electric currents. ;H "At the rccciving-slatioii the pill- jH sations encounter a galvanometer, jH which is influenced more or less ac- t cording to their intensity. ;H "This instrument, called a 'cord gal- H vauomctcr,' consists of two copper H wires on which is fastened a very I H thin leaf of aluminum; it is fixed be- I M twecu the poles of au elcctroma- I H gent. When a current passes, the H wires arc deviated, and the little al- H uminum lea.f changes position; it M plays the part of a sort of valve, let- ting pass more or less of tc light of M a Nernst lamp precisely similar to H that of the scuding-station. What H happens then? H "The light-ray, or rather the part tM of it that has been allowed to pass, 'fl meets a second glass cylinder covered ''H with a black cylinder pierced with a M hole and having a spiral motion pre- M cisely synchronous with that of the H transmitting cylinder. This glass cyl- H indcr carries, rolled upon it, a sensi- tive film. Evidently each point oi H this film will receive exactly the quan- H tity of light necessary to tcproducc H the corresponding point of the pho- M togVaphic film at the transmitting H "Finally, the scries of lines, which H are slightly undulating, because of M the spiral motion of the apparatus t and the devices of regulating their M synchronism, forms a reproduction M of the original image. M "The apparatus that assures this M synchronism is of extreme delicacy, M and consists of two conical wheels M nested together." M "Professor Korn has surmounted, M with much ingenuity, another diffi- M culty 'th.-t Has hitherto interfered H with work of this kind what has H been called the 'inertia1' or 'fatigue' M of the selenium. Wc read; M "This curious metal, when it is M caused to do work, shows, at the end M of a short time, a sort qf unwilling- M ucss to become a conductor under' the M influence of the light ray, and thus fl to let the current pass in the circuit M of which it forms a part. This prop- 1 crty it has in common with many M of the cclicr'i'rs used in wireless M telegraphy. M "It became necessary to 'decohere' M these mechanically, :nd this has led M to the use of 'spontaneously deco- M licring' coherers. Professor Korn M triumphs over the 'inertia' of the scl- M cnium by means of his 'compensator,' M which was quite recently described M before the Academy oi Sciences. fl "This compensator consists of a M second plate of selenium in the .same M circuit, and of two accumulators cor- H responding to the two plates. The M inertia of the selenium is compensated M at the receiving station by a galvauo- M meter which controls the illumination of that of the first. By this means H Professor Korn has done away with the lluffincss and indecision so cvi- M dent on the first photographic prints H at the receiving station. "Such is the present state of tcjc- pho'ography. Wc may assert, with H its learned promoters, that, apart M from all researches on 'seeing at a H distance,' it will doubtless furnish H the means of realizing this with brief H "Wc may look forward to the time H when the telephone probably the H wireless telephone will be joined to H the 'telopt,' that is to say, to the dc- H vice for long-distance vision, so that H two interlocutors, hundreds of miles H apart, may sec each other as they arc H talking. Thus there will be a sort H of transportation of the 'personality,' H which would have seemed, a few years H since, entirely within the domain of H the imagination." 'Translation made B for The Literary Digest. M |