The article apparently says “translated.” If that means “wrote out an English translation,” that seems a bit implausible, and also, for that matter, not particularly useful. The goal (at least my goal) is not to translate, but to read fluently with comprehension and without translating. But if “translated” is loose language for “read with comprehension,” 400 lines of Vergil’s Aeneid or Ovid’s Metamorphoses or Homer a night is not implausible. (You need to read metrically, however, aloud or mentally. You can cover more ground if you read metrically.)
Other texts, however, take more time. Even Vergil’s Georgics, for example, have many obscure and technical words that I for one need to look up, despite having read through several times. 400 lines of Pindar or Propertius a night – forget about it. (We’re just measuring verse here.) Propertius, for example, is full of obscurities because the transmitted text is in atrocious shape. With almost every verse, you need to consider a raft of variants, conjectures, and proposed transpositions, in order to make any sense of the text, and even then, you’re often not quite sure whether you’ve got it right.
And you wouldn’t want to read 400 lines of Horace’s Odes or Vergil’s Georgics a night: texts such as those need to be read slowly (but, again, metrically) if you want to extract the most out of them because every syllable is pregnant with meaning. That’s true of the Aeneid, too, of course, but much of the Aeneid can be read more rapidly, in my experience.
In my own experience, the texts you’ve been reading – Horace’s Satires – are very difficult, so don’t be discouraged. For one thing, they require a substantial amount of extraneous knowledge that you need to find in commentaries. The compression of thought and the concomitant use of allusion to achieve the compression contribute to the difficulty. I personally would not expect to be able to read 400 lines of Horace’s Satires in an evening’s sitting. I doubt the subject of the New Yorker article would be able to, either.
