A method is described by which the rate of transfer of disperse dye vapor to cellulose acetate film can he measured continuously. The results of experiments in which two model compounds and three actual dyes are apphed in this manner are given. Saturation values. partition coefficients absorption isotherms, and heats of absorption are given, and the dyes are discussed in terms of molecular structure. The application of the results to the dry-heat method of dyeing synthetic fibers is mentioned.