“Whoa—” she calls to Ariel, tugging the reins, trying to press her weight into the bouncing stirrups with the balls of her feet. Raw earth and tawny matted grasses pass beneath her, a close-cropped frozen knit pounding by, the damp, matted hair of babies, crushed quartz, mica, tourmaline ground to mud, the morning sky creating itself in streaks of garnet and azure. She braces, tensing for the slip of her heels out of the irons, a repeat of the runaway gallop hugging the neck of the first horse she ever rode, careening down the streets of Cambridge just after she’d arrived in England, the honking and dodging cars, pedestrians diving into shop fronts, she clinging for dear life, anything to keep from under those hammering hooves. Remember: Fear runs down the reins. “Whoa—” she calls, checking the reins once again, feeling for the horse’s mouth, straightening her spine, and Ariel slows enough to bounce Sylvia backward into the saddle, where the driving force of one of the horse’s hind legs bumps her up and out just enough to miss the jolt of the opposite leg. Rising trot: Head up, hips forward, knees bent, weight in heels, beginners take the mane. As she rises Sylvia grabs a handful of mane halfway up the horse’s neck. Suddenly, as her seat touches down behind the pommel and the mare’s muscular haunch sends her up again, her body catches the rhythm of the horse’s gait. Her pelvis tilts, and again she meets the saddle on the downbeat. She’s got it; she’s posting, rising with the motion of the stride, perfectly balanced with the thrust of the horse’s body.