and location is in each case derivative from the
corresponding relation of situation in a way which I will proceed to
explain.

Also location in the timeless space of some time-system is a relation
derivative from location in instantaneous spaces of the same
time-system. Accordingly location in an instantaneous space is the
primary idea which we have to explain. Great confusion has been
occasioned in natural philosophy by the neglect to distinguish between
the different types of objects, the different types of situation, the
different types of location, and the difference between location and
situation. It is impossible to reason accurately in the vague concerning
objects and their positions without keeping these distinctions in view.
An object is located in an abstractive element, when an abstractive set
belonging to that element can be found such that each event belonging to
that set is a situation of the object. It will be remembered that an
abstractive element is a certain group of abstractive sets, and that
each abstractive set is a set of events. This definition defines the
location of an element in any type of abstractive element. In this sense
we can talk of the existence of an object at an instant, meaning thereby
its location in some definite moment. It may also be located in some
spatial element of the instantaneous space of that moment.

A quantity can be said to be located in an abstractive element when an
abstractive set belonging to the element can be found such that the
quantitative expressions of the corresponding characters of its events
converge to the measure of the given quantity as a limit when we pass
along the abstractive set towards its converging end.

By these definitions location in elements of instantaneous spaces is
defined. These elements occupy corresponding elements of timeless
spaces. An object located in an element of an instantaneous space will
also be said to be located at that moment in the timeless element of the
timeless space which is occupied by that instantaneous element.

It is not every object which can be located in a moment. An object which
can be located in every moment of some duration will be called a
'uniform' object throughout that duration. Ordinary physical objects
appear to us to be uniform objects, and we habitually assume that
scientific objects such as electrons are uniform. But some sense-objects
certainly are not uniform. A tune is an example of a non-unifor