British history
This novel is set in Britain in the late 19th century, about a hundred years before the actual historical invention of the computer. This means that the setting becomes an imagery of contrast. The different setting will allow the changes brought about by computer technology to be more visible. British history is actually a pretty important part of the novel, in fact, because the authors seem to be interested in preserving not just the aesthetic of 19th century Britain, but also they preserve the historical details of the era.
Computer technology
As mentioned, the second imagery of the book is the imagery that is introduced by Charles Babbage's Analytical Engine, the title, Difference Machine which can computer equations quickly and which leads to a major breakthrough in computer technology. This imagery is speculative, but it basically works this way: If the breakthroughs of the 20th century had been accomplished a hundred years earlier, then how might that technological revolution have played out?
Power and government
The changes are not merely changes in how people calculate math equations. The book shows an entire shift in economy and government because of the changes in technology. This leads to a major rift in the old way of life and the new way of life. This happens in both economy and government, as the novel depicts. The characters are navigating changing power structures attempting to secure safety and power in the new economy. The changes are marked by a move away from monarchical government.
Apocalypse and change
The apocalyptic imagery of the novel comes in the sense of urgency and doom that the rapid changes bring about. The stakes are immediately heightened to a great degree, because it is not clear to the characters which of their assumptions about society and power need to be adjusted. Just as the new powers are those who are clever with technology, the new upper class will be those who are clever socially, understanding what a major technological change like this will mean. They are asked to speculate, adapt, or else perish with the dying age.
