At the beginning of “An Episode of War,” the narrator describes how the lieutenant divides up his troop’s supply of coffee grounds, using verbal irony in the process:
The lieutenant was frowning and serious at this task of division. His lips pursed as he drew with his sword various crevices in the heap, until brown squares of coffee, astoundingly equal in size, appeared on the blanket. He was on the verge of a great triumph in mathematics.
When the narrator describes the lieutenant’s “task of division” as “a great triumph in mathematics” because he was able to separate the coffee grounds into equal pieces, they are using verbal irony. That is to say, the narrator very much does not believe this to be a “great triumph of mathematics,” and they refer to it that way to sarcastically point out how far from triumphant this mundane moment is.
This is one of the many moments in the story in which Crane highlights the less-than-romantic nature of war, communicating to readers that war is made up of many mundane moments between inexperienced young men who know very little about the true horrors of battle. Separating the coffee is only a “triumph” because they know little of real triumph.