In his story "Dusk," author Saki employs light/dark imagery to create a certain mystery in his narrative; in addition, his skillful utilization of irony and satire enhances the startling effect of his story's ending.
For instance, the mysterious tone is established with the light/dark imagery in the exposition of the narrative as Saki writes of the "faint moonlight," "shadowed gloom," and the "gloaming hour" which disguises the "unconsidered figures" who move with "bowed shoulders." In this atmosphere of abject figures in the twilight, Saki's character of Norman Grotsby, who takes cynical pleasure in watching the others, seems somewhat superior since he has only failed in what Saki terms a more "subtle ambition." With this subtle word choice which suggests Grotsby's superiority, and his demonstration of mental acumen as he detects the flaw in the young man's tale of being lost after stepping out of his hotel for soap, the satiric irony of Gortsby's error in thinking that the soap discovered under the bench after the young man departs belongs to him is startling.
In order to further enhance the irony and satire, Saki's diction creates credibility on the part of the young man. For example, Saki writes that the young man possesses a "look of disarming frankness," and he makes "an eloquent pause." When Gortsby does not seem to believe him, the youth displays "a suggestion of resentment in his voice." Further, this diction disarms the unsuspecting reader as the youth
threw a good deal of warmth into the last remark, as though perhaps to indicate the hope that Gortsby did not fall short of the requisite decency.
Thus, the diction of the narrative about the young man who talks in the shadows of twight to the cynical Gortsby, who seems the superior man of the dialogue, enhances the satire of human nature as well as the startling irony of the last line of the story.