Mr. Williamson's active career was also chequered by the diabolical nature of the crimes which kept him most busily employed. Fenianism might have been found written on his heart, like Calais on Queen Mary's, and, closely interwoven with it, anarchism and nihilism in all their phases. He knew no peace when foreign potentates were the guests of our royalties; Scotland Yard was, in fact, held responsible for the safety of Czar and Emperor, and the police authorities depended chiefly on Williamson, with his consummate knowledge and long experience of exotic crime. It [Illustration: OLD SCOTLAND YARD.] was Williamson who was first on the scene when infernal machines had exploded, or might be expected to explode at any moment. To him the officer who is nowadays our chief mainstay and defence against these outrages, Inspector Melville, owes much of his insight into the peculiar business of the "special section," as this important branch of criminal investigation is called. The latter not long ago disposed very ingeniously of a case which might have led to serious mischief. Fertility of resource with great promptitude in action are among Mr. Melville's strongest and most valuable traits. Well, on one occasion, during the visit to England of a foreign Sovereign, information was received that one of his subjects residing in this country, and by no means loyal to him, intended to do him an injury the first time he could get near him in public. It happened that at that moment the imperial visitor was on the point of joining in a great procession, which had either actually started, or would start in the course of an hour or so. The malcontent was employed as cellarman to a wine and spirit merchant or publican with large wine vaults. There was no time to lose, and Melville made the best of his way to the place, saw the proprietor, and inquired for a certain brand of champagne he wished to purchase. The master called his man and sent them down together into the cellars. The cellarman went first with a light; at the bottom of the staircase he unlocked the wine cellar and went in--still first. [Illustration: INSPECTOR MELVILLE.] "What wine is that over yonder?" asked Melville carelessly, and the man crossed over to the far end of the vault to look before he answered. This was all the astute officer wanted. Instantly seizing the opportunity, he stepped back out of the cellar, closed the door promptly and locked it. The irreconcilable cellarman was a prisoner, and was left there perfectly safe from any temptation to carry out the fell purpose of which he was suspected. After the procession was over he was set free.