Mr. James nodded his head, but did disturb himself; in fact, he rose with a scowl upon his face, and followed this polite old gentlemen all round the shop, placing himself close to his elbow. One might almost suppose that he suspected him, so close and assiduous was his assistance. But the visitor, accepting these attentions as if they were customary, and the result of high breeding, went slowly round the shelves, taking down book after book, but buying none. Presently he smiled again, and said that he must be moving on, and very politely thanked Mr. James for his kindness. "Nowhere," he was so good as to say, "does one get so much personal kindness and attention as at Emblem's. Good-morning, Mr. James; good-morning, my friend." Mr. James grunted; and closed the door after him. "Ugh!" he said with disgust, "I know you; I know your likes. Want to make your set complete--eh? Want to sneak one of our books to do it with, don't you? Ah!" He looked into the back shop before he returned to his paste and his slips. "That was Mr. Potts, the great Queen Anne collector, sir. Most notorious book-snatcher in all London, and the most barefaced. Wanted our fourth volume of the 'Athenian Oracle.' I saw his eyes reached out this way, and that way, and always resting on that volume. I saw him edging along to the shelf. Got another odd volume just like it in his wicked old hand, ready to change it when I wasn't looking." "Ah," said Mr. Emblem, waking up from his dream of Iris and her father's letter; "ah, they will try it on. Keep your eyes open, James." "No thanks, as usual," grumbled Mr. James as he returned to his gum and his scissors. "Might as well have left him to snatch the book." Here, however, James was wrong, because it is the first duty of an assistant to hinder and obstruct the book-snatcher, who carries on his work by methods of crafty and fraudulent exchange rather than by plain theft, which is a mere brutal way. For, first, the book-snatcher marks his prey; he finds the shop which has a set containing the volume which is missing in his own set; next, he arms himself with a volume which closely resembles the one he covets, and then, on pretense of turning over the leaves, he watches his opportunity to effect an exchange, and goes away rejoicing, his set complete. No collector, as is very well known, whether of books, coins, pictures, medals, fans, scarabs, book-plates, autographs, stamps, or anything else, has any conscience at all. Anybody can cut out slips and make a catalogue, but it requires a sharp assistant, with eyes all over his head like a spider, to be always on guard against this felonious and unscrupulous collector.