Which didn’t mean she couldn’t hear anything. She could hear the wind. A phrase that didn’t really do justice to the soundscape now being rendered by the array of miniature speakers. "The canid smelled the forest" was a completely different sentence from "The man smelled the forest," not because the words had different meanings, but because the canid’s olfactory apparatus was infinitely superior to that of the man. In a loosely analogous way, the real-time, three-dimensional sonic portrait of the wind generated by the glider’s onboard systems and rendered by the helmet’s speakers was as far beyond what she could sense with unaided ears as the canid’s scenting of the forest was beyond the man’s. For the vehicle had lidars pointed in all directions, looking out into the air to a range of several hundred meters and seeing its myriad currents, shears, and vortices. To convey all of that information in sound was impossible, but what came through was more than enough to tell Kath Two where she wanted to go: namely, where the energy was. And right now the symphony of tones, whooshes, crackles, and rustlings told her that her intuition yestereve had been more or less correct. The wind climbed the slope from the lake in a fairly continuous sheet, but as it molded itself over the brow of the hill, the wind higher up, on the outside track, had to go faster in order to keep up with the ground layer. There was a gradient in speed between the wind aloft and that at the ground. She could use it.