Whitecaps began to roll down the faces of some of the cross-chop waves, and Sax immediately checked into the ship’s weather system to see what the wind speed was. The ship had it at thirty-two kilometers per hour. So this was about the speed at which the crests of waves were first knocked over. A simple matter of surface tension against wind speed, calculable, in fact . . . yes, the appropriate equation in fluid dynamics suggested they should start to collapse at a wind speed of thirty-five kilometers per hour, and here they were: whitecaps, startlingly white against the water, which was a dark blue, Prussian blue Sax thought it might be. The sky today was almost sky blue, slightly em-purpled at the zenith, and somewhat whitened around the sun, with a metallic sheen between sun and the horizon under it.

“What are you doing?” Ann said, sounding annoyed.

Sax explained, and she listened in stony silence. He didn’t know what she might be thinking. That the world was somewhat explicable— he always found that a comfort. But Ann . . . well, it could be as simple as seasickness. Or something from her past, distracting her; Sax had found in the weeks since the experiment at Underhill that he was often distracted by some past incident, rising unbidden from a great bulk of them in his mind. Involuntary memory. And for Ann, that might include negative incidents of one kind or another; Michel had said she had been mistreated as a child. It still seemed to Sax too shocking to believe. On Earth men had abused women; on Mars, never. Was that true? Sax did not know for sure, but he felt it was true. This was what it meant to live in a just and rational society, this was one of the main reasons it was a good thing, a value. Possibly Ann would know more about the reality of the situation these days. But he did not feel comfortable asking her. It was clearly contraindicated.

“You’re awfully quiet,” she said.

“Enjoying the view,” he said quickly. Perhaps he had better talk about wave mechanics after all. He explained the groundswell, the cross chop, the negative and positive interference patterns that could result. But then he said, “Did you remember much about Earth, during the Underhill experiment?”

“No.”

“Ah.”