Gregory paused in his inspection of the artificial growths to ask, “D’you know why ships have gardens, Caulfield?”

“I think so,” the ex-Engineer replied, his voice flat and distorted through the phones. “Claustrophobia among the passengers and crew was a problem even in my day, especially in ships on the longer runs. Ships tend to be cramped, which begets claustrophobia and allied neuroses. These can get out of control and wreck a ship as surely as a reactor blow-up. Yet theoretically there is enough empty space outside to cure any claustrophobe, or even knock him over the hump into agoraphobia, if it could be used right.

“What they did was to steer a path between the two phobias,” Caulfield went on, “by rigging the outer hull of a ship to look like a garden. Besides giving the crew something to do on a long trip, this meant that a man who was beginning to feel the bulkheads closing in on him could go out and sit or walk on the hull and fool himself into thinking that he was in an Earthly garden at night with the stars shining brightly. There were anomolies [sic], of course, but it was all very reassuring to the subconscious mind. It is easy to fool a mind that wants to be fooled, especially one’s own, and the garden therapy worked in most cases.”

“ That’s right,” said Gregory, trying to hide his surprise. There had been a strange air of authority in Caulfield’s tone in spite of the distortion. This was certainly an unusual Engineer.

Gregory and Nolan continued to examine random sections of the ship’s hull. Close inspection revealed the grass-like areas to be the product of skillful painting on a roughened plastic surface thin enough for their boot magnets to hold the metal plating underneath. The flowers were also plastic as were the bushes and creepers which broke up the ‘lawn’ at intervals of ten or twenty yards — due to a careless job of painting one of the bigger leaves still had the name of a food company on its underside. But each and every item of this luxuriant but artificial greenery was solidly anchored down — in the case of the longer stems or branches they were held in several places to the numerous metal projections from the ship’s hull. Gregory gave several of them a sharp tug to make sure of this.