On Negative After-Images, and Their Relation to Certain other Visual Phenomena . nables him to vary the speed at will or to keep it sensibly wire attached at right angles to the axis of the disc taps a strip ofcard at every revolution, producing a succession of audible clicks, whichcan, when desired, be compared with the taps of a metronome beatingseconds. The most usual speed is from five to six turns per disc apparatus is supported at such a height from the table thatwhen the disc is turning in the direction of the arrow the spectrumprojected upon the screen I (fig. 3)
On Negative After-Images, and Their Relation to Certain other Visual Phenomena . nables him to vary the speed at will or to keep it sensibly wire attached at right angles to the axis of the disc taps a strip ofcard at every revolution, producing a succession of audible clicks, whichcan, when desired, be compared with the taps of a metronome beatingseconds. The most usual speed is from five to six turns per disc apparatus is supported at such a height from the table thatwhen the disc is turning in the direction of the arrow the spectrumprojected upon the screen I (fig. 3) is eclipsed at the moment whenthe iris-diaphragm in the screen P is beginning to be exposed to thewhite light. During about one-half of a revolution both the diaphragmand the slits are shielded by the disc. The width of the spectrumprojected upon the slit-screen I (lag. 3) is 2*9 cm., and its visiblelength in a dimly lighted room about 7 cm.; the measured distancebetween X 6870 (Fraunhofer line B) and /X4115 (iron line betweeng and H) was approximately 6*1 cm. Fig. 4. Fifh j « i ? — ^1philtrans09930384
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Keywords: ., bookcentury1900, bookdecade1900, bookidphiltrans099, bookyear1901
