Dehydration by infra-red ray of white cotton-cloth, 178% wet basis percentage was examined graphs of electric power consumption against wet percentage were obtained, by which the mechanism of the dehydration was studied, the conclusion are as follows.
(1) At the dehydration, the use of the wave length λm=1.45μ a is the most advantageous.
(2) As the method of dehydration, illumination upon a pile of from 3 to 5 sheets of the specimen is the most profitable.