Although Mrs. Ambrose stood quite still, much longer than is natural, the little boys let her be. Some one is always looking into the river near Waterloo Bridge; a couple will stand there talking for half an hour on a fine afternoon; most people, walking for pleasure, contemplate for three minutes; when, having compared the occasion with other occasions, or made some sentence, they pass on. Sometimes the flats and churches and hotels of Westminster are like the outlines of Constantinople in a mist; sometimes the river is an opulent purple, sometimes mud-coloured, sometimes sparkling blue like the sea. It is always worth while to look down and see what is happening. But this lady looked neither up nor down; the only thing she had seen, since she stood there, was a circular iridescent patch slowly floating past with a straw in the middle of it.