His dreams were affected also by the throngs of people whom he had watched in London. He was haunted by "the tyranny of the human face." He says:-- "Faces imploring, wrathful, despairing, surged upwards by thousands, by myriads, by generations, by centuries: my agitation was infinite, my mind tossed, and surged with the ocean." Sound also played a large part in the dreams. Music, heart-breaking lamentations, and pitiful echoes recurred frequently in the most magnificent of these nightly pageants. One of the most distressing features of the dreams was their vastness. The dreamer lived for centuries in one night, and space "swelled, and was amplified to an extent of unutterable infinity." To present with such force and reality these grotesque and weird fancies, these vague horrors, and these deep oppressions required a powerful imaginative grasp of the intangible, and a masterly command of language. In no other work does De Quincey reach the eminence attained in the _Confessions_, although his scholarly acquirements enabled him to treat philosophical, critical, and historical subjects with wonderful grace and ease. His biographer, Masson, says, "De Quincey's sixteen volumes of magazine articles are full of brain from beginning to end." The wide range of his erudition is shown by the fact that he could write such fine literary criticisms as _On Wordsworth's Poetry_ and _On the Knocking at the Gate in Macbeth_, such clear, strong, and vivid descriptions of historical events and characters as _The Caesars, Joan of Arc_, and _The Revolt of the Tartars_, and such acute essays on unfamiliar topics as _The Toilette of a Hebrew Lady, The Casuistry of Roman Meals_, and _The Spanish Military Nun_. He had a contemplative, analytic mind which enjoyed knotty metaphysical problems and questions far removed from daily life, such as the first principles of political economy, and of German philosophy. While he was a clear thinker in such fields, he added little that was new to English thought. The works which rank next to _The Confessions of an English Opium-Eater_ are all largely autobiographical, and reveal charming glimpses of this dreamy, learned sage. Those works are _Suspiria de Profundis (Sighs from the Depths), The English Mail Coach_, and _Autobiographic Sketches_. None of them contains any striking or unusual experience of the author. Their power rests upon their marvelous style. _Levana and Our Ladies of Sorrow_ in _Suspiria de Profundis_ and the _Dream Fugue_ in the _Mail Coach_ are among the most musical, the most poetic, and the most imaginative of the author's productions.