Swallow-tailed

Walking somewhat slowly by reason of his concentration, the boy—an ancient man in some phases of thought, much younger than his years in others—was overtaken by a light-footed pedestrian, whom, notwithstanding the gloom, he could perceive to be wearing an extraordinarily tall hat, a swallow-tailed coat, and a watch-chain that danced madly and threw around scintillations of sky-light as its owner swung along upon a pair of thin legs and noiseless boots.