David Bodanis buries a political comment in a book about electricity

An elegant political comment lies hidden in a footnote in Electric Universe, a book by David Bodanis that describes the discovery and use of electricity, through which the Laquedemitasse is slowly working his way.  Mr. Bodanis explains the difference between a cipher and a code.  In a cipher, a rule (or a machine) changes text character by character.  A simple substitution cipher might move each letter one place forward, so that HAPPY BIRTHDAY becomes IBQQZ CJSUIEBZ.  A code, Mr. Bodanis says, is different from a cipher; a code is "where one word is used to stand for another, as with a child’s code in which, for example, the words national embarrassment are substituted wherever the word shrub has been written."