To make such a statement I have borrowed two epithets from the terminology of physical science. Energy is described by physicists as kinetic and potential. Kinetic energy is force actually exerted. Potential energy is force that a body is in a position to exert. Applying these terms to language, without attempting too strict an analogy, I wish to define literature, or rather the medium of literature, as a combination of kinetic with potential speech. In this combination the two are coincident. There is no such thing in literature as speech purely kinetic or purely potential. Purely kinetic speech is prose, not good prose, not literature, but colourless prose, prose without atmosphere, the sort of prose that M. Jourdain discovered he had been speaking all his life. It says things. An example of purely potential speech may be found in music. I do not think it can be made with words, though we can give our minds a taste of it in listening to a meaningless but narcotic incantation, or a poem in a language that we do not understand. The proportion between kinetic and potential speech and the energy of the combination varies with different works and the literature of different ages. There is no literature to which it is impossible to apply the formula. Let us try to clarify it by example and particularisation. It may be asked, what of ballad poetry in which there is much so stated as to approach purely kinetic speech? Does not the admitted power of a sea-song, a song whose words are utterly trivial, disprove our assertion? It does not; for to such songs or chanties the music to which they are sung has given a quality of potential speech, without which they would be worthless and speedily forgotten. In that case the words and the melody respectively represent kinetic and potential speech. It has been very truly said that a prima-donna can turn the alphabet to poetry by the emotional power of her voice.