much may still be trusted to the imagination, which would conflict with our ordinary perception and notion of probability. The most convenient course in this, as in other matters, is a happy mean; in other words, while not wholly excluding the claim of purely natural fact and perception, we may still permit ourselves considerable license in our attitude to both. (_ββ_) The unity of _time_ is a precisely similar case. In the pure realm of imaginative idea we may no doubt, with no difficulty, combine vast periods of time; in the direct vision of perception we cannot so readily pass over a few years. If the action is, therefore, of a simple character, viewed in its entire content and conflict, we shall do best to concentrate the time of such a conflict, from its origin to its resolution, in a restricted period. If, on the contrary, it demands character richly diversified, whose development necessitates many situations which, in the matter of time, lie widely apart from one another, then the formal unity of a purely relative and entirely conventional duration of time will be essentially impossible. To attempt to remove such a representation from the domain of dramatic poetry, on the _primâ facie_ ground that it is inconsistent with the strict rule of time-unity would simply amount to making the prose of ordinary facts the final court of appeal, as against the truth of poetic creation. Least of all need we waste time in discussing the purely empirical probability that as audience we could, in the course of a few hours, witness also, directly through our sense, merely the passage of a short space of time. For it is precisely in the case where the poet is most at pains to illustrate this conclusion that, from other points of view, he well-nigh invariably perpetrates the most glaring improbabilities. (_γγ_) In contrast to the above examples of unity, that of _action_ is the one truly inviolable rule. The true nature, however, of this unity may be a matter of considerable dispute. I will therefore develop my own views of its significance at greater length.