The London, Edinburgh and Dublin philosophical magazine and journal of science . , p. 234. X Communicated by Lord Kelvin, Images in the Field of a Hittorfs (Crookes) Tube. 309 With this end in view we replace the photographic plateor the fluorescent screen by a plate of ebonite. The electricfield is maintained for two or three minutes, after which theaction of the tube is arrested and the ebonite plate withdrawnfrom its position. By a quick movement the objects on theplate are thrown to the ground and we proceed to develop theimages by sprinkling over the plate a mixture of sulph
The London, Edinburgh and Dublin philosophical magazine and journal of science . , p. 234. X Communicated by Lord Kelvin, Images in the Field of a Hittorfs (Crookes) Tube. 309 With this end in view we replace the photographic plateor the fluorescent screen by a plate of ebonite. The electricfield is maintained for two or three minutes, after which theaction of the tube is arrested and the ebonite plate withdrawnfrom its position. By a quick movement the objects on theplate are thrown to the ground and we proceed to develop theimages by sprinkling over the plate a mixture of sulphur andminium. As is well known, the sulphur adheres to thoseportions which are positively, the minium to those which arenegatively electrified. Thus the colour of the spots showsthe electric condition of the shadows, and the comparison oftheir configuration with that of the objects indicates themodifications introduced in the mode of action of the field. The tube used in our experiments had the shape of a pearwith flattened base (fig. 1) ; k is the kathode, a the anode. In the central part of the base there was a fluorescent spotabout a centimetre in diameter ; and at some distance therewas a less intense fluorescent zone concentric with the a few centimetres below the tube is placed a plate orscreen of ebonite b, which rests ordinarily on the rim of aglass vessel 13 cm. in diameter and 21 cm. in depth. Themanner of supporting the plate is quite immaterial providedthat the support is clear of the central portion of the the screen, or at any rate its central portion, is sur-rounded by air on both sides. The objects are placed eitherabove or below the plate ; in the latter case they are heldby projecting arms which are bent over the rim of the images were developed on both faces of the screen ; wehave also employed two screens placed one on the other anddeveloped the images on the four faces of the screens. 310 MM. Oumoff and Samoiloff on Elec
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Keywords: ., bookcentury1800, bookdecade1840, bookidlondon, booksubjectscience
