★ The polar air was dismaying, not monstrous as it had been in the previous incursions. A street-sweeping truck raised a solid-looking cloud of dry dust on West End and left it hanging in the crosswalk for a dauntingly long time after the light changed. The sky was the color of salt-dust, too. The sun faded out and in. Pigeons fluffed and waddled in a patch of turf where the deep cold had preserved the last thin snowfall down between the grass blades, as if it were a specimen of long-term significance. Some new kind of blue melting salt was at work on the sidewalks. A pile of dog turds had been so freeze-dried as to resemble wood shavings. The late sky was subtly mottled.