Rummaging through the Lansdall-Welfare database again, looking for Faërie creatures, I find only disappointment. Was Georgian → Victorian → Edwardian → Georgian England such a prosy place? “Fairy” doesn’t rank among the top million words, though “fairyland” just barely makes the cut. “Elf” shows up only in 2-grams that look like “him elf” and “her elf”, which I interpret to mean that the letter “s” is poorly suited to optical character recognition. Hobs, ogres, orcs, ettins, and goblins all appear, but just barely. One in ten million words is their order of magnitude. Dragons are 10-100 times more common than any of those; getting a job in heraldry was evidently a good career move.
Dwarfs, though, are almost impossible typographical errors. There are dwarf fruit trees and so forth, but that should form a stable background against which we can see trends. And so it appears.
The big spike in “dwarf” in 1938 is almost certainly Disney’s Snow White, but I’m going to pretend it’s also due to The Hobbit because The Hobbit has twice as many dwarfs. (“Dwarves” doesn’t appear in the database.)
But what’s with the dwarfs in 1871? I consulted the fount of all trivial information, and found that 1871 saw the publication of Through the Looking-Glass and What Alice Found There, by Lewis Carroll and At the Back of the North Wind by George MacDonald. Alas, no dwarfs in either, though MacDonald did throw in a dwarf primrose for me. 1870 saw the publication of Brewer’s Dictionary of Phrase and Fable.  That seems like a stretch. Google Books says the only books it knows about that mentioned dwarfs that year are two dictionaries.
General Tom Thumb made his world tour from 1869 to 1872, and he was in the British isles in 1871-2. Let’s suppose that’s the explanation for the big spike in dwarf-mentioning in 1871. If we subtract out the gardeners’ background with a 10-year moving average, then the press mentions of dwarfs dropped by 75% from 1871 to 1872, which means he didn’t come home a minute too soon.
English newspapers are published by muggles.
 Also Venus in Furs, by Leopold von Sacher-Masoch. Finding meaning in that coincidence is beyond me.