MEASUREMENT IMPORTANT IN PSYCHOLOGY.--Measurement has always been of importance in psychology; but it is only with the development of experimental psychology and its special apparatus, that methods of accurate measurements are available which make possible the measurement of extremely short periods of time, or measurements "quick as thought," These enable us to measure the variations of different workers as to their abilities and their mental and physical fatigue;[1] to study mental processes at different stages of mental and physical growth; to compare different people under the same conditions, and the same person under different conditions; to determine the personal coefficient of different workers, specialists and foremen, and to formulate resultant standards. As in all other branches of science, the progress comes with the development of measurement. METHODS OF MEASUREMENT IN PSYCHOLOGY.--No student of management, and of measurement in the field of management, can afford not to study, carefully and at length, methods of measurement under psychology. This, for at least two most important reasons, which will actually improve him as a measurer, i.e.-- 1. The student will discover, in the books on experimental psychology and in the "Psychological Review," a marvelous array of results of scientific laboratory experiments in psychology, which will be of immediate use to him in his work. 2. He will receive priceless instruction in methods of measuring. No where better than in the field of psychology, can one learn to realize the importance of measurements, the necessity for determination of elements for study, and the necessity for accurate apparatus and accuracy in observation. Prof. George M. Stratton, in his book "Experimental Psychology and Culture,"--says "In mental measurements, therefore, there is no pretense of taking the mind's measure as a whole, nor is there usually any immediate intention of testing even some special faculty or capacity of the individual. What is aimed at is the measurement of a limited event in consciousness, such as a particular perception or feeling. The experiments are addressed, of course, not to the weight or size of such phenomena, but usually to their duration and intensity."[2] The emphasis laid on a study of elements is further shown in the same book by the following,--"The actual laboratory work in time-measurement, however, has been narrowed down to determining, not the time in general that is occupied by some mental action, but rather the shortest possible time in which a particular operation, like discrimination or choice or association or recognition, can be performed under the simplest and most favorable circumstances.[3] The experimental results here are something like speed or racing records, made under the best conditions of track and training. A delicate chronograph or chronoscope is used, which marks the time in thousandths of a second."