For the novel reality of a danger is perceived only through the medium of that new thing, not assimilable to anything that we already know, to which we give the name “an impression” and which is often, as in the present case, epitomised in a line, a line which defines an intention and possesses the latent potentiality of the action which has given it its particular form, like the invisible line of this falling bomb . . . .

[Proust, Time Regained]