a melody" we not only remember the preceding tone, but _expect_ the succeeding ones. Such interplay of present, past and future is requisite for every kind of _meaning,_ for every _unit of thought_; and among others, of the meaning, the _thought,_ which we contemplate under the name of _shape._ It is on account of this interplay of present, past and future, that Wundt counts feelings _of tension_ and _relaxation_ among the _elements_ of form-perception. And the mention of such _feelings,_ i.e. rudiments of _emotion,_ brings us to recognise that the remembering and foreseeing of our acts of measurement and orientation constitutes a microscopic psychological drama--shall we call it the drama of the SOUL MOLECULES?--whose first familiar examples are those two peculiarities of visible and audible shape called _Symmetry_ and _Rythm._ Both of these mean that a measurement has been made, and that the degree of its _span_ is kept in memory to the extent of our expecting that the next act of measurement will be similar. _Symmetry_ exists quite as much in _Time_ (hence in shapes made up of sound-relations) as in _Space;_ and _Rythm,_ which is commonly thought of as an especially musical relation, exists as much in _Space_ as in _Time_; because the perception of shape requires Time and movement equally whether the relations are between objectively co-existent and durable marks on stone or paper, or between objectively successive and fleeting sound-waves. Also because, while the single relations of lines and of sounds require to be ascertained successively, the combination of those various single relations, their relations with one another _as whole and parts,_ require to be grasped by an intellectual synthesis; as much in the case of notes as in the case of lines. If, in either case, we did not remember the first measurement when we obtained the second, there would be no perception of shape however elementary; which is the same as saying that for an utterly oblivious mind there could be no relationships, and therefore no meaning. In the case of Symmetry the relations are not merely the lengths and directions of the single lines, that is to say their relations to ourselves, and the relation established by comparison between these single lines; there is now also the relation of both to a third, itself of course related to ourselves, indeed, as regards visible shape, usually answering to our own axis. The expectation which is liable to fulfilling or balking is therefore that of a repetition of this double relationship remembered between the lengths and directions on one side, by the lengths and directions on the other; and the repetition of a common relation to a central item.