Two things are going "out" from the Great Isabel here: Linda's light, and Giselle's "charm." They represent contrasting attitudes that the individual can take toward society. The image of the beam striking the sunet is an image of artifice, strife, and ultimate futility, made more meaningful by the symbolism in which the "expiring" sunset evokes glorious dream-ideals being born only to die. Such is the society of duty and unifying ideals. In contrast to all that effort, Giselle's "indolence" has a "promising mysteriousness"; it is "intoxicating"; it has an "impregnating" fertility. Note that it has nothing to do with the sunset; it addresses "shadows" and "night," symbolic of the subjective inner world.