"No." He reached for Farr; the boy took his hand, meekly, like a child. "Come on, Farr. It's not food they'll be short of in that damn Hospital, but strength, and courage, and ingenuity. And..."

There was an explosion from the heart of the City — no, not an explosion, Adda thought, but an immense tearing sound, a huge exhalation.

There was a moment of stillness. Then a shock passed through the City.

The very fabric of the structure seemed to flex. The little room rattled around them, and the fragments of crockery, already smashed, rattled in a thin hail against the walls.

When the tremor had passed, Farr asked, "What was that? Another settling in the Magfield?"

"I don't think so. That was sharper — more abrupt... Come, lad. Let's move."

Ito kissed them both quickly on the cheek. "Be safe," she said.

The Hospital of the Common Good was in the upper Downside, and Adda decided that the quickest way to get there — the most likely to be clear — would be through Pall Mall. So he and Farr Waved along one of the main artery-streets toward the broad axis of the City. It was a little easier to move now, Adda found; most people must have reached whatever destination they had been looking for — or, he reflected sadly, be lying hurt in some corner of the City. But the Air-cars were an increased menace. The cars soared along the emptying streets behind teams of terrified Air-pigs; several times the Human Beings had to lurch aside to stop themselves being run down. Once they came across a car which had embedded itself nose-first into a shop-front. There was no sign of the driver, but the Air-pig team was still attached to its harness. The pigs strained against their restraints, their circular mouths wide as they screamed.

Farr loosened the harness. Released, the pigs fled away into the shadows of the corridors, caroming from the walls like toys.

They reached the junction of the artery-street and the Mall. Adda rested at the street's rectangular lip for a moment, then prepared to launch himself out into the main shaft. But Farr grabbed his arm and held him back. The boy pointed downward. Adda stared into his face, then squinted down, blinking to clear his good eyecup.

The lower end of the Mall — the huge spherical Market — was filled with light. Too much light, which glinted from the guide rails, stall sites, the huge execution Wheel... Yellow Air-light, which flooded into the heart of the City from a new, ragged shaft that cut right through the Mall itself, just above the Market.

So here was the cause of the shock they had experienced with Ito.

The edges of the shaft were neat — so neat that Adda might almost have thought it was man-made, another avenue. But the cross-section of this shaft was irregular — formless, nothing like the precise rectangles and circles which defined Parz — and it was off-center, askew, too wide.