March of time, arrow of time, time warp

This is the kind of thing that’s buzzing through my head as I work on the next book. (It’s an N-gram, computed on the fly by Google here, from the contents of all the books they [in some cases illegally] scanned from libraries.)

(Were you wondering about those “time warp” occurrences in the early 19th century? They come from passages like this (1812): “By keeping up the sluices, and drains, and banks, the land can be refreshed at any time. Warp land has had crops of flax …”)