The mistake evokes the "Americanos, perhaps" who set out in search
of the legendary treasure of Azuera.
It is a prefigurement of the Azuera-like spell that the silver will cast on all
connected with it, including Mrs Gould in her own way. The "shadows of the
road" represent the dark side of the San Tomé campaign, the perils
involved in any quest for Azuera's wealth.