Unlike the others, he couldn’t make much of a contribution to shipboard life. Couldn’t climb the mast and help with the sail-work and rope-work, like Gentle and Poppy, lacked Fragrant’s and Coral’s navigational skills and Teal’s ability to conjure meals in the tiny galley. Gentle had fashioned a replacement for his lost cane from the twisted stem of a thornbush from the clifftop heath, but it wasn’t much use on the deck of the windjammer and Pilgrim mostly got about by hauling himself along lines and rails, his weak leg dragging behind him. In truth, he found being at sea more unnerving than being at the mercy of the women and their Invisible College. It was only his second time aboard a proper ship – the river ferry between Highwater Reach and Concord didn’t count – and while the sturdy coastal trader ship had plodded as steadily as a draft mara through straits and channels, the windjammer seemed as nervous as a gazehound. It was constantly in motion. Not merely thrusting forward, but pitching up and down and from side to side. Pilgrim had only been properly seasick once, when they had been forced to spend a night anchored close to a rocky shore while a storm thrashed the sea into huge waves and lumps of flying foam, rain blew sideways and lightning danced at the horizon, but he was faintly unsettled all the time, and very much misliked it on the occasions when they cut a chord across an inflection in the coast and left all sight of land behind. The sea was intimidatingly vast and the windjammer was a slender, unstable sliver of wood and canvas seven paces across and seventy from stem to stern. A tiny island at the mercy of elemental forces utterly indifferent to the lives of its crew.

One day, they cut through a shoal of flying fish scudding above the waves and Gentle chased down and clubbed several which landed on the deck. Pilgrim studied one before Gentle filleted it, made sketches of its slim but sturdy body and the wing-like pectoral fins and smaller pelvic fins that enabled it to glide for short distances after it had thrust itself above the waves with vigorous movements of its tail. The pectoral fins were each as wide as his hand when outstretched, their elegant curved profile, resembling a bird wing, supported by bifurcate rays.

It was a pleasing example of convergent selection, he told Poppy, and she told him that engineers had borrowed the shape of flying-fish fins for the wings of sailplanes that, after being launched from hot-air balloons, could glide for thirty or forty stades, surveying the land below and using the new plate cameras to record it. She studied the behaviour of bears, said that she would love to use a sailplane to survey their territories and mating leks in the northern wilderness.