London
Imagery is used to describe London in the mid-1800s, during the cholera epidemic. Overall, London is presented as being overpopulated, unhygienic, and dangerous:
"The dark reality of urban poverty: to live in such as world was to live with the shadow of death hovering over your shoulder at every moment."
The Thames
In an attempt to rid the city of miasma, one solution was to put all waste into the river Thames. The narrator uses imagery to describe how the Thames would become a "river of sewage."
Eureka Moments
Johnson uses imagery to describe "great intellectual breakthroughs usually happen in practice." He explains that it is rarely an isolated moment with one person, but is also not only "standing on the shoulders of giants." He uses imagery to describe how "great breakthroughs are closer to what happens in a flood plain: a dozen separate tributaries converge and the rising waters lift the genius high enough that he or she can see around the conceptual obstructions of the age."
