"A snorter, which produced a grovel"

I have proceeded through my happy-birthday biography of J.R.R. Tolkien (a gift from Roy) and am now enjoying my happy-birthday edition of Tolkien's letters (ditto). Most of us who've delved into Tolkienish minutiae know that his compositors helpfully "corrected" some of his spelling in Lord of the Rings. I am giggling over his account of it, in his letter to his son Christopher:

The galleys are proving rather a bore! There seem such an endless lot of them; and they have put me very much out of conceit with parts of the Great Work, which seems, I must confess, in print very long-winded in parts. But the printing is very good, as it ought to be from an almost faultless copy; except that the impertinent compositors have taken it upon themselves to correct, as they suppose, my spelling and grammar: altering throughout dwarves to dwarfs; elvish to elfish; further to farther; and worst of all, elven- to elfin. I let off my irritation in a snorter to A. and U. [Allen and Unwin, his publishers], which produced a grovel.

A snorter, which produced a grovel. How tickled he must have been.