A glazed black bag with hinged bottom, which may be placed over any article and automatically swallow it is another ingenious invention.

All these, however, are byways of crime. There is much more to be absorbed by the learner in police science. Here he is shown the different types of jemmies, and bars of steel so fashioned that they may be used as chisels or levers. Here are bunches of skeleton keys which, in the hands of experts, will open any ordinary lock in the world. A massive steel implement shaped like a gigantic tin-opener, and used to rip open the backs of safes, is another item in the collection. There are vice-like tweezers which, when properly screwed up, will cut quietly through the bolts of, say, a jeweller's shutters.

Still more scientific is a complicated apparatus with tubes in which oxygen and acetylene gas are used to melt through safes with a fierce heat—a quieter, less clumsy, and more effective method than the use of explosives.

It would take more space than is at my command to detail all the practical instruction which is afforded by the object lessons the young constable has in the museum. Not only is he initiated into wrinkles and tricks which he may meet any day, but he is shown into those more subtle branches of crime which few but specialists enter.

Coining is a case in point. There is a complete coiner's outfit—which, for obvious reasons, I shall not describe—and the process is explained from A to Z. Now-a-days the "smasher" is a difficult individual to circumvent. He works preferably with real silver, and with coins like sixpences and shillings which are not so closely scrutinised as those of higher denominations. Of course, even in a genuine sixpence the silver is not worth its face value.

A step higher in the criminal hierarchy is the forger. Of his handicraft, specimens are not lacking. There are relics seized when a notorious forger went into forced seclusion for ten years some time ago. He manufactured Bank of France thousand-franc notes and foreign bonds, and even used lithographic stones to imitate the water-mark. Photography played an important part in his operations.

I have shown, sketchily perhaps, how the primary function of the museum is carried out. But it has another and allied interest of great importance to all interested in police science.

One may study the stages by which the professional criminal has adapted the work of invention to his ends, and mark at the same time how the swindler always strikes the same old chord of credulity in human nature.

Dropped in one of the corners is a heavy bar of brass, originally in the possession of an early gold-brick swindler. Mr. Albert Blair Hunter, of Wilmington, Delaware, U.S.A., communicated with two gentlemen in this country, stating that a wealthy relative had died possessed of considerable property, among which was a box of gold from Klondike, value £12,000. For various plausible reasons he was willing to dispose of it to them for £2,000. The good, simple-minded souls went to New York, and handed solid English money to that amount over to Mr. Albert Blair Hunter, of Wilmington, Delaware, U.S.A. For what? A bar of brass worth perhaps twenty shillings sterling.