Three major types of the ordinal scaling have been suggested; the principle of frequency distribution, the comparisons with known scale, and the principle of mutual comparisons. Two major types of the application of the second principle are analysed. A known scale can be given either in a form of set of categories, the order of which is determined according to the meanings of the words used, or in a form of set of objects, the order of which has been determined according to the results of previous experiments. The former is called a prescription scale and the latter an empirical scale. Problems concerning the combined use of the second principle and the principle of frequency distribution are discussed.