Around the World in Eighty Days reads like a 19th-century travel guide with a plot, shuttling back and forth between a highly descriptive style and a style that emphasizes plot and character more than setting. For example, in Chapter 17, the narration slips a description of mangoes into an exchange between Passepartout and Aouda:
Passepartout, who had been purchasing several dozen mangoes—a fruit as large as good-sized apples, of a dark-brown colour outside and a bright red within, and whose white pulp, melting in the mouth, affords gourmands a delicious sensation—was waiting for them on deck. He was only too glad to offer some mangoes to Aouda, who thanked him very gracefully for them.
The initial purpose of this sentence is to develop Passepartout and Aouda's relationship and characterization. Passepartout appears to be a generous man. Aouda, meanwhile, comes into the reader's view as a polite woman who defies racist stereotypes (established earlier in the novel) about Indian excess and greed. Partway into the sentence, the narration seems to realize that the European reader may never have encountered mangoes. It thus uses em dashes to pause the main sentence and interject a detailed description of mangoes that sounds authoritative an objective, as though it is drawn straight from a travel guide.
The highly detailed descriptions lend the novel a sense of authority about the world. Many readers believed that Around the World in Eighty Days, published serially in the newspaper, was a real account of someone's journey around the world. Sentences like this may have contributed to that mistake. Verne was not necessarily malicious in allowing readers to believe Fogg was "real." Rather, he was playing with the idea (popular in the 19th century) that fiction could serve an important and authoritative role in shaping real social institutions. The highly detailed descriptions are especially emblematic of the growing trend of realism in novels. In the late 19th century, novels would often include far more descriptive details than they had prior to this. These details served to conjure a vivid, realistic picture of a novel's setting and allowed fiction authors to make a new kind of commentary on the real world.