After dinner, while talking to some guests, Marlow recalls more details about the much-discussed "Patna incident." It was his "guardian devil," he says, that caused him to have such a keen interest in the inquiry.
It seems that four officers deserted the Patna when they believed it to be sinking, leaving the rest of the crew and the 800 Moslem pilgrims to be cooked alive in the hot steam of the sinking ship, leaving them as though they were "only natives." The Patna, however, did not explode and sink; it arrived safely at Aden, a port on the Red Sea, and now its officers had to stand trial for deserting their ship.
Only Jim, however, was available to testify. After the obese captain received a tongue-lashing from the Harbor Master, he squeezed his soft, massive bulk into a tiny carriage and vanished. Marlow talked to the two engineers who were hospitalized, but he was unable to discover any relevant information about the affair. The first engineer swore that there were thousands of pink toads under his hospital bed, and the second engineer swore that the Patna did indeed sink and that it was full of reptiles.
Ultimately, it was not Jim's "crime" that interested and disturbed Marlow; it was Jim's weakness, for despite Jim's cowardly flaw, and despite the fact that he deserted the Patna, Marlow admits that he himself would have "trusted the deck" to Jim "on the strength of a single glance." And yet, "it wouldn't have been safe."
The end of Chapter 4 mentioned an observer named Marlow who was present at Jim's trial, and now that Jim is placed before us as a man on trial, we must begin, through Marlow's eyes, to make judgments about Jim. Marlow will now select and objectify our views of Jim.
Marlow is theoretically telling the story to some unnamed listeners (one of them, we know, is named Charley), and many readers have questioned this device — that is, in Conrad's "Author's Note," he writes that critics have "argued that no man could have been expected to talk all that time, and other men to listen so long." Conrad answered the objection by saying that, first, some members of Parliament speak for six hours in Parliament without stopping and that, second, Jim's story is so intriguing that it would hold the attention of the listeners.
Chapter 5, however, still does not enlighten the reader as to the true nature of the Patna episode. Rather, Conrad focuses on the four officers from Marlow's point-of-view: the captain is presented as "the fattest man in the whole blessed tropical belt" and is elephantine in nature and thoroughly obscene and disgusting in every way. The other three men are all contrasts to the captain. The chief engineer and the second engineer are almost insignificant, and in total contrast to all of them is Jim — the magnificent, broad-shouldered youth whose very appearance seems to inspire confidence.
Most important, however, is the fact that Marlow realized that Jim is "one of us." This phrase, as noted earlier, will become one of the principal themes of the novel. That is, if Jim is "one of us," then any of us readers, finding ourselves in the same predicament as Jim found himself, would probably react exactly as Jim did. Therefore, throughout the novel we should gauge Jim's actions against how we ourselves might likely act in a similar situation.
But, as yet, as noted above, we still do not know what the horrible, shameful, disgraceful action was that Jim committed; we know only that everyone reacted violently and with deep resentment and indignation.
Marlow prepares us for Jim's remaining all alone in port to testify by emphasizing in great detail how the captain suddenly "departed, disappeared, vanished, absconded." The second engineer is also dispensed with, and the chief engineer drank himself into such a coma that he couldn't testify. These drastic actions intrigue the reader as to the nature of the forthcoming testimony.