"Coleridge, to many people, and often I have heard the complaint, seemed to wander; and he seemed then to wander the most when in fact, his resistance to the wandering instinct was greatest - viz., when the compass and huge circuit by which his illustrations moved travelled farthest into remote regions before they began to revolve. Long before this coming round commenced most people had lost him, and naturally enough supposed he had lost himself. They continued to admire the separate beauty of his thoughts, but did not see their relations to the dominant theme."
The Collected Writings of Thomas De Quincey, ed. David Masson, vol. II, pp. 152-3.