抄録
A photometric measurement of the rate of dyeing was carried out with an attachment consisting of two multiple optical glass fibers. Oneside terminals of the optical fibers were dipped in the dye solution facing to each other in a short distance, and the other terminals were set toward the light source and the phototube, respectively in an electrophotometer. As the optical absorbance of dye solutions was instantaneously measured and recorded, an experimental error due to a time-lag of measuring which arises in the usual method when changing the dye concentration were able to be completely avoided.
The rate constant of dye exhaustion was estimated quickly from the recording data according to the convenient equations derived from the exponential or the hyperbolic formula.
