Airships past and present, together with chapters on the use of balloons in connection with meteorology, photography and the carrier pigeon . roduced. If alarge number of expo-sures are to be made, asaving in weight mayresult from the use of amagazine camera hold-ing several plates. Withcameras of the newesttype it is possible tomake about twelve ex-posures in half a minute,and from this it is evidentthat the changing of theplates is simply andquickly done. But theiruse can hardly be recom-mended, even if a typeof magazine is used inwhich the changing ofthe plates is effected by simply turning
Airships past and present, together with chapters on the use of balloons in connection with meteorology, photography and the carrier pigeon . roduced. If alarge number of expo-sures are to be made, asaving in weight mayresult from the use of amagazine camera hold-ing several plates. Withcameras of the newesttype it is possible tomake about twelve ex-posures in half a minute,and from this it is evidentthat the changing of theplates is simply andquickly done. But theiruse can hardly be recom-mended, even if a typeof magazine is used inwhich the changing ofthe plates is effected by simply turning them over in succession,and so preventing one plate from rubbing against the next. Thereis indeed a serious objection to their use, which lies in the factthat the changing of plates causes a great deal of dust to settle onthe sensitive surface of the gelatine, and produces a partial blurringof the image. There is no means of removing this dust beforemaking the exposure. Further, the plates are very liable to bebroken by being dashed against one another if the landing shouldbe accompanied by any violent bumping. So that we finally come. Fig. 194,—Aiguille Verte, taken with theVautier-Dufour apparatus by the VegaCompany, of Geneva. PHOTOGRAPHIC OUTFIT FOP BALLOON WORK. 311 to the conclusion that nothing is better than the old flexible shutters, used in some double-backs are not to berecommended for balloon work; the linen backing is very liableto contain dust, which cannot easily be removed, and as theshutter is unrolled the dust may settle on the sensitive best plan is to use double-backs with vulcanite are easily cleaned, and if they are rubbed with a piece ofwashleather they be-come charged with elec-tricity, and remove anydust that may be on thesurface of the plate whenthey are pulled advantage liesin the fact that they canbe pulled entirely out ofthe double-back. If aspring closes the slit inthe double - back, thelight
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Keywords: ., bookcentury1900, bookdecade1900, bookpubl, booksubjectaeronautics
