"I don't know whether you are aware of the fact, Sir Antony," he remarked, "but you have a very exceptional piece of old jewellery here. The stone is one of the finest emeralds I have ever seen, and as for the setting--" he again peered curiously at the delicate gold tracery--"well, I don't want to express an opinion too hastily, but I am inclined to put it down as ancient Moorish work of a remarkably beautiful kind." He paused. "I trust that you wouldn't consider it a liberty, Sir Antony, if I inquire whether you could tell me anything of its history." "It belonged to my cousin's great-grandmother," said Tony placidly. "That's all I know about it at present." "Indeed," said Mr. Mason, "indeed! It would be of great interest to discover where it was obtained from. A stone of this quality, to say nothing of its exceptionally rare setting, is almost bound to have attracted attention. I should not be surprised to find it had figured in the collection of some very eminent personage." "What do you suppose it's worth?" asked Tony. Mr. Mason hesitated for a moment. "Apart from any historical interest it may possess," he replied slowly, "I should put its value at something between five and seven thousand pounds." "Really!" said Tony. "I had no idea my cousin's great-grandmother was so extravagant." He picked up the brooch. "I wonder if you could find me a nice strong case for it, Mr. Mason. Somebody might run into me at Brooklands this afternoon, and it would be a pity to get it chipped." The old jeweller accepted the treasure with almost reverent care, and calling up one of his assistants entrusted it to the latter's charge. In a minute or so the man returned with a neatly fastened and carefully sealed little package, which Tony thrust into his pocket. "Well, good-bye, Mr. Mason," he said, "and thank you so much. If I find out anything more about my cousin's great-grandmother I will let you know." Bowing and beaming, Mr. Mason led the way to the door. "I should be most interested--most interested, Sir Antony. Such a remarkable piece of work must certainly possess a history. I shouldn't be surprised if it had belonged to any one--any one--from Royalty downwards." Half-past twelve was just striking when Tony came out of the shop. The distance is not far from Bond Street to Covent Garden, but as intimate students of London are aware the route on occasions is apt to be a trifle congested. It was therefore about ten minutes after the appointed time when Tony pulled up outside the Cosmopolitan and jumping down from the car made his way straight through the hall to Donaldson's private sanctum, where the ceremony of settling up was invariably conducted.