Anthony's photographic bulletin for .. . possibility for the results to be traceable to the violet light, or toany visible light, and the only visible sign of excitatioii was a slightlygreenish tinge in the tube. The ordinary incandescent current wasreduced to seven amperes and passed through an induction coil andthrough the Crookes tube. The plate-holder was placed at one end ofthe tube, the various substances being held by means of black wax ina little paper tray against the pressboard slide. After an exposureof one hour the plate was developed, and the accompanying half-toneshows the relati
Anthony's photographic bulletin for .. . possibility for the results to be traceable to the violet light, or toany visible light, and the only visible sign of excitatioii was a slightlygreenish tinge in the tube. The ordinary incandescent current wasreduced to seven amperes and passed through an induction coil andthrough the Crookes tube. The plate-holder was placed at one end ofthe tube, the various substances being held by means of black wax ina little paper tray against the pressboard slide. After an exposureof one hour the plate was developed, and the accompanying half-toneshows the relative transparency of the various materials used to the X. Compare with Half-Tone. Cardboard, painted black on both sides 56 millimeter. Tinfoil 01 Thin glass 19 Thin plate of aluminium 168 Crystal of carbonate of lead millimeters. Thick plate of aluminium ] American tin foil (mostly lead) 032 millimeter. rtz crystal 9 iar millimeters. Platinum foil 02 millimeter. Thin aluminium foil 023 ; h plate j<lass millimeters. the arrangement and thicknesses of the materials used beingshown in the zinc etching. In other experiments that we have seenin tl tion, .in exceptionally powerful current was used with complicated apparatus, Leyden jars, etc., and the tube was heated ta point l the eye. In theibed above, conducted by Professor Rood, the tem,f the tube never sensibly exceeded thai oi the surroundingatmosphere, and the result was .ill that could l><- desired ; so that there 73 is no obstacle in the way of the production of these photographs if oneis the posse
Size: 1513px × 1652px
Photo credit: © The Reading Room / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1800, bookdecade1870, booksubjectphotogr, bookyear1870
