It is the fault of some excellent writers – De Quincey’s first impressions on seeing London suggest it to me – that they express themselves with too great fullness and detail. They give the most faithful, natural, and lifelike account of their sensations, mental and physical, but they lack moderation and sententiousness….they say all they mean. Their sentences are not concentrated and nutty. Sentences which suggest far more than they say, which have an atmosphere about them, which do not merely report an old, but make a new, impression; sentences which suggest as many things and are as durable as a Roman aqueduct; to frame these, that is the art of writing. Sentences which are expensive, towards which so many volumes, so much life, went; which lie like boulders on the page, up and down or across; which contain the seed of other sentences, not mere repetition but creation. If De Quincey had suggested each of his pages in a sentence and passed on, it would have been far more excellent writing.
Thoreau recorded this entry in his journal on August 22, 1851.