ABSTRACT
In all scientific work measurement is not only desirable but necessary. Certain of the measures we make are necessarily gross and relatively inaccurate, but in all work the attempt should be made to use as accurate measures as are needed for the determination of the limits of the phenomena with which we deal. When we measure a room for a carpet it is not necessary that we shall measure its length and breadth to the nearest hundredth of an inch. Measurement to the nearest inch or half inch is quite sufficient. If we wish to weigh food for the purpose of sale or purchase it is not necessary that it should be done to the nearest grain. Weight to the nearest ounce, and in a few cases to the nearest half or quarter ounce is sufficiently exact for food, whereas when we weigh drugs it is often necessary that our measure be taken to the nearest tenth of a grain. If we employ an individual it is not important to measure his working time to the nearest second but it is sufficiently accurate to take the time to the nearest minute, sometimes to five minutes or even to ten minues. These usual methods of dealing with certain everyday problems may well be considered by both the investigator and the professional man in the measurement of the phenom116ena with which they have to deal. Whenever possible a measurement Of some sort should be applied to the thing which is under consideration but the limits of the measure required must be kept in mind.
