. Photographic pastimes : a series of interesting experiments for amateurs for obtaining novel and curious effects with the aid of the camera. Fig. 5.—Photograph cf Lightning. To develop the negatives the sulpho-pyrogallic acid developer is very suitable,but I have also got good results witheikonogen, or the combined eikonogenand hydroquinone developer. OTHER ELECTRIC PHENOMENA. Interesting photographs are those oithe electric spark, which the latter pro- 32 PHOTOGRAPHIC PASTIMES. duces itself on the sensitive plate. Forthis experiment an ordinary frictionelectric machine is sufficient, agains
. Photographic pastimes : a series of interesting experiments for amateurs for obtaining novel and curious effects with the aid of the camera. Fig. 5.—Photograph cf Lightning. To develop the negatives the sulpho-pyrogallic acid developer is very suitable,but I have also got good results witheikonogen, or the combined eikonogenand hydroquinone developer. OTHER ELECTRIC PHENOMENA. Interesting photographs are those oithe electric spark, which the latter pro- 32 PHOTOGRAPHIC PASTIMES. duces itself on the sensitive plate. Forthis experiment an ordinary frictionelectric machine is sufficient, againstthe conductor of which a gelatine plateis kept (in the dark) with the moistenedhand so that it finds itself at a slightdistance vertically from it. On turningthe machine fine sparks are emitted onthe sensitive film, which, on develop-ment, will give very characteristic, palm-branch-like, ramified and curved sparks emitted by the negative con-ductor show, however, figures of an. Figs. 6 and 7.—The Electric Spark. Positive Pole. Negative Pole, ELECTRIC PHENOMENA. 33 entirely different character from thoseemitted by the positive pole. (See and 7.) According to the investigationsmade hitherto this phenomenon seems todepend not so much on a chemical de-composition as on a direct electrolyticalaction. (12.) Instead of letting the electric sparkreproduce for itself, it can as well bephotographed by means of the cameraand the lens. For this purpose it isnecessary to previously focus the spotwhere the electric spark passes fromthe one conductor to the other, whichmay be done by means of a luminoussubject (for instance, with a platinumwire made incandescent by the electriccurrent), which should be placed in themiddle of the ideal line which combinesthe two conductors. After focussing, thissubject is removed, the room darkened,the lens uncovered, and, after withdraw-ing the sliding door, the electric machine 34 PHOTOGRAPHIC PASTIMES. is put into action. The fi
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Keywords: ., bo, bookcentury1800, bookdecade1890, bookidphotographicpast00schn
