His big Idea was the idea of the Moving Fortress. The dream of a French engineer, the old, abandoned dream of the forteresse mobile, had become Nicky's passion. He claimed no originality for his idea. It was a composite of the amoured train, the revolving turret, the tractor with caterpillar wheels and the motor-car. These things had welded themselves together gradually in Nicky's mind during his last year at Cambridge. The table in Nicky's sitting-room at the top of the house in Chelsea was now covered with the parts of his model of the Moving Fortress. He made them at the Works, one by one; for the Morss Company were proud of him, and he had leave to use their material and plant now and then for little ideas of his own. The idea of the Moving Fortress was with him all day in the workshops and offices and showrooms, hovering like a formless spiritual presence among the wheeled forms. But in the evening it took shape and sound. It arose and moved, after its fashion, as he had conceived it, beautiful, monstrous, terrible. At night, beside the image of the forteresse mobile, the image of Desmond was a thin ghost that stood back, mournful and dumb, in the right-hand corner of the vision.
But the image of Desmond was there.
At first it stood for Nicky's predominant anxiety: "I wonder when Desmond will have finished the drawings."
The model of the Moving Fortress waited upon Desmond's caprice.
The plans of the parts and sections had to be finished before these could be fitted together and the permanent model of the Moving Fortress set up. The Moving Fortress itself waited upon Desmond.
For, though Nicky could make and build his engine, he could not draw his plans properly; and he could not trust anybody who understood engines to draw them. He was haunted, almost insanely, by the fear that somebody else would hit upon the idea of the Moving Fortress; it seemed to him so obvious that no gunner and no engineer could miss it. And the drawings Desmond made for him, the drawings in black and white, the drawings in grey wash, and the coloured drawings were perfect. Nicky, unskilled in everything but the inventing and building up of engines, did not know how perfect the drawings were, any more than he knew the value of the extraordinary pictures that hung on the walls and stood on the easels in her studio; but he did know that, from the moment when he took Desmond into his adventure, he and his Idea were dependent on her.
He didn't care. He liked Desmond. He couldn't help it if Drayton disapproved of her and if Dorothy didn't like her. She was, he said to himself, a ripping good sort. She might be frightfully clever; Nicky rather thought she was; but she never let you feel it; she never talked that revolting rot that Rosalind and Dorothy's other friends talked. She let you think.
It was Desmond who told him that his sister didn't like her and that Frank Drayton disapproved of her.
"They wouldn't," said Nicky, "if they knew you." And he turned again to the subject of his Moving Fortress.
For Desmond's intelligence was perfect, and her sympathy was perfect, and her way of listening was perfect. She sat on the floor, on the orange and blue cushions, in silence and in patience, embracing her knees with her long, slender, sallow-white arms, while Nicky stamped up and down her studio and talked to her, like a monomaniac, about his Moving Fortress. It didn't bore her to listen, because she didn't have to answer; she had only to look at him and smile, and nod her head at him now and then as a sign of enthusiasm. She liked looking at him; she liked his young naïveté and monomania; she liked his face and all his gestures, and the poise and movement of his young body.