The descent of the silver from the mountain is one of the most thrilling passages in the novel, but it also has a symbolic meaning, in which the ideal of San Tomé descends from purity into corruption. Before the transit we see San Tomé as a unifying force, spreading security and optimism through the land; after the transit, we immediately learn that San Tomé has financed war and entered into partisan politics. Compare this descent from the mountain with that of the railway in Chapter 1-5.

Note also Captain Mitchell's apparently unrelated remark just before the descent of the silver: "That, sir, was a mistake." I.e., it is a mistake to bring a dream-ideal down from the heights of pure aspiration and into contact with the corrupting and corruptible world.