Good movement rests, first of all, on clearness; secondly, on right emphasis; and thirdly, on something already mentioned in connection with both clearness and right emphasis,--suspense. This means a straining forward of interest, a compelling desire to know what will happen next. Whether a hearer is totally at a loss to know what will happen, but eager to ascertain; partly guesses what will take place, but deeply desires to make sure; or almost holds back so greatly does he dread an anticipated situation, he is in a state of suspense, for be it willingly or unwillingly on his part, on sweeps his interest.
There should be good movement within the scene, the act, and even the play as a whole. It is, however, easily checked. If scenes or characters not essential are allowed place within a play, it has been shown on pages 87-89 that this may interfere with either clearness or good emphasis. They will hurt the movement of the play. Closely related as a possible danger are necessary scenes not well placed. Often shifting part of a scene or act makes all the difference between sustained and interrupted suspense. For example, a young man, after some quarrelsome words, threatens to shoot his sister. As they stand facing each other, steps are heard outside. A group which enters brings about an amusing scene. Good as it is, it may kill the suspense created by those two tense figures, if it switches interest wholly or in large part from them. If it does, any effective picking up the scene between the angry brother and sister, when the visitors go out, may be impossible. On the other hand, so write the scene that the audience, never diverted in its attention to those two figures, feels that the moment the visitors leave the quarrel will be resumed with greater intensity just because of the interruption: then there will be no loss of tension. Just here lies the important point: suspense once created must never be allowed to lapse so long as to be lost. A scene for contrast or to renew the power of desired emotional response in the audience or to develop part of a correlated story may be introduced, but always what is put between something which makes the audience strain forward and its goal should leave it as eager, and preferably more eager for the solution.