a glimpse

There is a singular effect oftentimes when, out of the midst of engrossing thought and deep absorption, we suddenly look up, and catch a glimpse of external objects. We seem at such moments to look farther and deeper into them than by any premeditated observation; it is as if they met our eyes alive, and with all their hidden meaning on the surface, but grew again inanimate and inscrutable the instant that they become aware of our glances.

-- Nathaniel Hawthorne The Marble Faun