This translation dates from 1941, and I suspect it was made so that the author could prove he could do it. I don’t doubt his understanding of Latin; my problem is the archaic nature of the English. Did Edward Marsh really think this was the way to make Horace available to an English readership, or was the point really to demonstrate his own cleverness?
A sample will suffice (1.34):
For Jove, whose wont it is to ply
His zigzag levin mid a clouded sky
This day through the clear azure drove afar
His thundering coursers and flame-pinion’d car —
Brought up short by ‘levin’, I looked it up and found that it was a Middle English word for ‘lightning’. At this point I thought I’d be better off just reading the Latin. Horace does not on the whole puzzle his readers with obscure vocabulary.
Some biographical information about Edward Marsh may be found here.