Google has sorted the words from all those books they scanned, and you can now graph the popularity of words or phrases over the centuries:

love,war
http://ngrams.googlelabs.com/graph?content=love%2Cwar&year_start=1800&year_end=2008&corpus=0&smoothing=3

golf,television
http://ngrams.googlelabs.com/graph?content=golf%2Ctelevision&year_start=1800&year_end=2008&corpus=0&smoothing=3

france,england
http://ngrams.googlelabs.com/graph?content=france%2Cengland&year_start=1800&year_end=2008&corpus=0&smoothing=3

railways
http://ngrams.googlelabs.com/graph?content=railways&year_start=1800&year_end=2008&corpus=0&smoothing=3