ALL day long over the gray Islington Street October, casting pearly mists, had turned the sun to silver and made London a city of meditation whose tumbled roofs and parapets and glancing spires appeared hushed and translucent as in a lake's tranquillity. The traffic, muted by the glory of a fine autumn day, marched, it seemed, more slowly and to a sound of heavier drums. Like mountain echoes street cries haunted the burnished air, while a muffin-man, abroad too early for the season, swung his bell intermittently with a pastoral sound. Even the milk-cart, heard in the next street, provoked the imagination of distant armor. The houses seemed to acquire from the gray and silver web of October enchantment a mysterious immensity.