'Uniform' objects are objects with a certain smoothness in their temporal relations, so that they require no minimum quantum of time-lapse in the events which are their situations. These are objects which can be said to exist 'at a given moment.' For example, a tune is not an uniform object; but a chair, as ordinarily recognised, is such an object. The example of the chair, and the dissolution of its continuous materials with specific physical constants into assemblages of electrons, warn us that a problem remains over for discussion after we shall have defined the meaning to be assigned to 'uniformity.' 54.2 In order to explain more precisely the theory of uniform objects, it is convenient to make a few definitions: A 'slice' of an event in a time-system is that part of lying between two moments of , where both moments intersect . The two moments are called the terminal moments of the slice, and the volumes in which the terminal moments intersect are called the terminal volumes. For brevity a slice of in the time-system is called an '-slice of .' It follows from the continuity of events that any -moment lying between the terminal moments of an -slice of intersects in a volume. Such a volume is called an -section of the slice. A slice is itself an event which stretches throughout the duration bounded by its terminal moments. Thus if the duration be the specious present for some percipient, the slice of is the part of the event e which falls within that specious present. 54.3 The properties of uniform objects will be enunciated as a set of laws regulating their character. Law I. If be any time-system and be a situation of an uniform object , then an -slice of exists which is a situation of . Law II. If be any time-system and be a situation of an uniform object and ′ be an -slice of which is a situation of , then every -slice of ′ is a situation of . Law I can roughly be construed as meaning that if an uniform object has been situated in any event, then there is some period of time (in any time-system) during which it has existed; and in the same way Law II means that if an uniform object has existed during any period of time, then it has existed during any shorter period within that period. These laws are obvious as applied to uniform objects, but not so obvious for objects in general, as 'object' is here defined. For example a musical note cannot exist in a period of time shorter than its period of vibration, and a percipient whose specious present was too short could not hear it. It follows from law II that if an uniform object O is situated in an event and ′ be an -slice of which is a situation of , then an abstractive class of -slices converging to any -section of ′ can be found such that is situated in each member of the class. Hence evidently is located in every -section of ′. This is the conception of an uniform object being located in a spatial volume at a durationless moment of time.