The lawn out in front of the Cambridge library is wide and deep and striped with evening light that has passed through the dozen or so trees speckling the lawn. Speckle is perhaps not the right word. There is more lawn than tree, but at this hour only a little more lawn than shade. Near the entrance a big willow ripples in the wind next to an equally big elm with little crimson leaves that shimmer like coins.

Harvard held its graduation today, and beneath the shimmering coins have walked all manner of young graduates in their robes; new masters in their hoods; and even the occasional professor in velvet, on his way down the grocery store for a sandwich. When I arrived, ultimate frisbee was being played across the lawn, but I’ve been here a while and the game thinned and broke up as the sun sank. Now a small group sits near the end zone with their shoes off. Some are reading, one is napping, and the one wearing her Harvard t-shirt inside out is carefully folding a little paper airplane.

Midnight.

Somewhere out there – beyond my window pane lined with its little stacks of copper coins – there is a vent that persists in making a gentle whooosh’ing sound, day and night. During the day it constitutes the lowest, thinnest layer of the urban audioscape, but at night its whooosh’ing climbs up amongst the other sounds, surrounds them in its envelope and can at moments be caught trying to pass for a silence that it is rather significantly not. In fact, it serves merely to remind anyone who was raised between nights of true, haunting quiet that they are far, far away from home.

In that way these two versions of night – one of woosh’ing and the other of emptiness – are in perfect opposition, for where real silence serves to clarify the signs of nocturnal life, to magnify them as might binoculars a distant bird, the whooosh’ing muffles, it mutes, and to ears used to the richness of a rural night, feels rather as though the listener has suffered a great dimming of the senses.