The old German for Thunder was Donner. The change to Dunder for the poem was probably to bring it more in line with the English.
And how many people were typing in "Blixem"? As that is the actual spelling used in the poem - very likely to help the awkward rhyme for "Vixen"
Donner and Blitzen means thunder and lightning in German. Donder or Dunder is Dutch, lightning in Dutch is Bliksem so it was probably the German that was originally used before Moore, ahem, published it.
Google: Charles Fenno Hoffman for more on the 7 year publishing gap.
And how many people were typing in "Blixem"? As that is the actual spelling used in the poem - very likely to help the awkward rhyme for "Vixen"
Donner and Blitzen means thunder and lightning in German. Donder or Dunder is Dutch, lightning in Dutch is Bliksem so it was probably the German that was originally used before Moore, ahem, published it.
Google: Charles Fenno Hoffman for more on the 7 year publishing gap.