Final answer:
Madame Schachter's vision of the furnace in the story 'Night' serves as an example of foreshadowing, hinting at the future horrors of the Holocaust that the characters will encounter, notably the crematoria in concentration camps.
Step-by-step explanation:
In the story Night, Madame Schachter's vision of the furnace is an example of foreshadowing. This literary device is used by authors to give an advance hint of what is to come later in the story. In the context of the novel, which deals with the horrors of the Holocaust and the experiences of Jews in concentration camps, the furnace symbolizes the crematoria that were used for mass extermination.
The sight of the furnace prompts Madame Schachter to scream about fire and flames, which creates a sense of dread and impending doom amongst the other characters and forewarns the reader of the atrocities that they are soon to encounter.