It is not intended that the series of articles we propose publishing in these pages under the above title should in any way give rise to alarm, or be an incentive to disturbed and restless nights. On the other hand, a better knowledge of how crimes are concocted and ultimately carried into effect may, perhaps, provide a course of much-needed lessons usually omitted in one's early education. It is said that the public seldom trouble to protect themselves, and for a very good reason, they don't know how; and it is only by becoming on a more familiar footing with the manners and customs of those enterprising individuals who seek to shatter anything between our nerves and our residences, either by relieving us of our purse or planting a dangerous species of explosive at our front doors, that we are the better able to take care of ourselves, our relatives, and our belongings--ourselves, perhaps, for choice. At New Scotland Yard a large apartment is devoted to the exhibit of ten thousand and one records of crime, in the shape of the actual weapons, and what not, associated with particularly notorious, and, in some instances, almost historic, deeds. A visit to this place is the finest and most complete nerve-tester in the world! The authorities at New Scotland Yard have kindly placed this room and its contents at our disposal; and each of the separate cases, which severally contain exhibits of some distinctive branch of punishable offences, requires a chapter to itself. The most recently arrived exhibit is one which, at the present time, possesses a peculiar interest. In the centre of the room is a glass case, which provides a resting-place for mementos of the more important outrages and attempts and suspicious cases of discoveries of explosives which have called for the attention of Her Majesty's Inspectors of Explosives for the last fifteen or twenty years--Colonel V. D. Majendie, C.B., H.M. Chief Inspector of Explosives, and Colonel A. Ford; whilst Dr. Dupré has throughout been associated with these gentlemen as chemical expert. As an expert in explosives, no name is better known than that of Colonel Majendie, a man in the prime of life, of indomitable energy and immovable disposition; who may be singled out as being engaged in the two extremes of business and pleasure. His business: dynamite, gunpowder, and all the kindred blasting operatives; his pleasure: the "Children of Paules," as the choir boys of St. Paul's Cathedral used to be designated. In his room at the Home Office slabs of American dynamite, infernal machines, and detonators; in his rooms at home walls covered with portraits of these tuneful youngsters, many of them in the whitest of white surplices; while the drawers of his desk are brimming over with youthful letters from the past and present choristers of the great Cathedral. Colonel Majendie never destroys a dynamite relic--or a child's letter. Both are too precious. [Illustration: COLONEL MAJENDIE