You may find at Scotland Yard the mahogany leg of a parlour chair, with a number of wedges by its side, which tells a story of ingenuity as clever as anything of its kind ever conceived by any novelist. More than that, it reflects the greatest credit upon the skill of our detectives and police officials. These simple, harmless-looking little wedges were quite sufficient to get three men twenty years' penal servitude for burglary. It was in 1875. A number of burglaries were committed in a certain district in London. The almost invariably careful perpetrators were foolish on these particular occasions, for they left their wedges behind them. These were, however, treasured by the police. When the men were eventually arrested, it was found that a chair at their lodgings was minus a leg, and when the wedges were pieced together--hey, presto! here was the mahogany leg! There are other exhibits at New Scotland Yard equally interesting--simple little items which tell a big story and carry with them heavy punishments. In a case is a group of articles comprising a number of bullets, a wooden wedge, a truncheon case--showing bullet marks--a soft black felt hat, and two chisels. Above the case is an enlarged photo of one of the chisels. They are relics of the murder of Police-constable Cole, on December 1, 1882, by Thomas Henry Orrocks. Orrocks left behind him, in a turning out of Dalston Lane, where the affray took place, the old hat, the wooden wedge, and the two chisels. He was suspected. The discovery was made that he had been practising with a revolver at Tottenham Marshes, and a bullet found in a tree there was identical with those found in the constable's truncheon case. But the most convincing evidence was the fact that when the chisels were photographed the word "Rock" was found scratched near the handle. It is a fact, not generally known, that photography can render visible what the eye is quite unable to discern. It was sufficient to hang Thomas Henry Orrocks. [Illustration: WEDGES MADE FROM CHAIR-LEG.] [Illustration: RELICS OF THE ORROCKS CASE.] Perhaps, however, the button incident is the prettiest of all. What a warning to burglars! The relics consist of an old black overcoat with a broken bone button. The piece broken off is carefully preserved in a small wooden box. In January, 1874, a burglary was committed in the vicinity of Westminster. A little piece of freshly broken off bone button was foolishly left on the window-sill. This the police kindly and considerately took charge of. A man was suspected, but there was no evidence against him to justify an arrest. But an enterprising police-officer clung to that bit of button, and one night he chanced to come across a gentleman with a button that had a piece missing. [Illustration: A CONVICTING CHISEL.] "Halloa!" he exclaimed, "button broken, eh?" "Yes," replied the proprietor of the old black overcoat, "I've lost it. I don't know where it is."