In chapter XXVII, Mr. Fogg and Passepartout are on a train traveling across the western US, nearing Salt Lake City, Utah. Salt Lake City, has a large population of Mormons, a relatively new and very interesting religion. During this ride, a Mormon missionary, Elder William Hitch, hosts a lecture in his train car about Mormonism. Mr. Fogg has little interest, but Passepartout is interested, and attends the lecture.
Elder William Hitch is wearing black stockings, a black silk hat, a black waistcoat, black trousers, a black cravat, and dogskin gloves. Based on photos provided by the Utah Historical Society, this description does seem accurate, however this description is also probably fitting for most men of the time.
In his lecture, Elder Hitch addresses the Mormon religion, prophets, and religious persecution. In specific, the persecution that stems from the polygamous relationships that a tradition of the religion. This lecture took place on Dec. 5th, and in October of this same year, Bringham Young was arrested for Bigamy. This prompted many missionaries to speak about religious persecution. I was able to find some primary sources of speeches of prominent missionaries and they do explicitly mention the persecution of Bringham Young.