As for Castor, little as Mostyn knew of horses he was impressed by the animal's appearance. Stripped of his clothes, he appeared a black colt of such magnificent proportions as to give one the idea that he was a three-year-old, instead of a nursery youngster. After much talking, in which Mostyn took small part, the bargain was struck. In return for his cheque for a thousand pounds, Mostyn became the proprietor of "as fine an 'oss as the eye of man could look upon;" so William Treves put it. "'E 'as a terrific turn of speed," the trainer continued, "and there isn't a three-year-old in this country that can 'old 'im at a mile at weight for age. I borrowed a couple of Colonel Turner's youngsters the other day to try 'im with, an' 'e left 'em fairly standing still, and the Colonel's 'ed man went 'ome with a wonderful tale about 'em, although 'e didn't know I'd put an extra five pound on Castor. Take my advice, if you're set on winnin' next year's Derby, don't pull 'im out too often this year. 'E's entered for the Eclipse at Sandown and the National Produce Breeders' Stakes, and you might let 'im run about four times just to give 'im a breather and get 'im used to racecourse crowds. No man livin' can say to-day wot will win the Derby next year, but if 'e trains on and puts on more bone, as I expect 'e will, 'e must stand a grand chance." "You hear that? He'll win the Derby for you." Armitage smote his young friend heartily on the back as he spoke. "Take my word for it." Mostyn was content with his purchase, proud of himself. There was but one hitch, and that occurred later in the morning when Armitage and Treves had moved away to inspect a new arrival at the stables, leaving Mostyn standing alone, a little awkwardly, in the great square yard. A young man approached him, a tall, broad-shouldered youth, good-looking after a coarse and vulgar style. He was aggressively horsey in his attire, and wore a cap set at the back of his head, displaying sleek hair plastered down over his forehead. This, as Mostyn was subsequently to learn, was Jack Treves, the son of the trainer. He had a familiar way of speaking, and made use of slang which jarred at once upon Mostyn's ears. He began by making a few casual remarks, then he jerked his head in the direction of his father and of Captain Armitage. "I hear you've bought Castor," he said. "A fine horse, sir." "Yes," replied Mostyn, "I've bought the colt." "Well, it may be all right." Jack Treves shook his head doubtfully. "And of course the captain can do what he likes with his own--that is, if it is his own--but I'll bet there'll be ructions, for Castor's entered for the Derby in the name of Miss Armitage, and she's always looked upon him as her particular property." He stooped and picked up a wisp of straw, passing it between his fingers. "Her property?" faltered Mostyn. "I don't understand."