the Detectives would not, as now, be obliged to arrest the same person over and over again, only to see him go free every time. In June, 1870, a gentleman, passing through Bleecker street, on his way home, at two o'clock in the morning, was knocked down and robbed of his watch and money. He was struck with such violence by the highwayman that his jaw was permanently injured. He was very eloquent in his complaints of the inefficiency of a police system which left one of the principal streets of the city so unguarded, and was loud in his demands for the punishment of his assailant, and the recovery of the property stolen from him. The best Detectives in the force were put in charge of the case, and the highwayman was tracked, discovered and arrested. The friends of the culprit at once returned the stolen property to its owner, and promised to reward him liberally if he would not press the prosecution of their comrade, who was one of the leading members of a notorious and dangerous gang of ruffians from whose depredations the city had been suffering for some time. The offer was accepted, and the gentleman flatly refused to prosecute, and when compelled by the authorities to state under oath, whether the prisoner was the man who had robbed him, became so doubtful and hesitating that his identification was worth nothing. This, too, in the face of his previous assertion that he could readily identify the criminal. In spite of his misconduct, however, there was evidence enough submitted to secure the conviction of the prisoner, who was sentenced to an imprisonment of ten years. The Detectives are in constant telegraphic communication with other cities, and intelligence of crimes committed is being constantly received and transmitted. Criminals arrested for serious offences are photographed, and their pictures placed in the collection known as the "Rogues' Gallery." These likenesses are shown to strangers only under certain restrictions, but they aid the force not a little in their efforts to discover criminals. The amount of crime annually brought to light by the Detectives is startling, but it does not exhibit all the evil doings of the great city. "The Police Commissioners of New York," says Mr. Edward Crapsey, "have never had the courage to inform the public of the number of burglaries and robberies annually committed in the metropolis; but enough is known in a general way for us to be certain that there are hundreds of these crimes committed of which the public is not told. The rule is to keep secret all such affairs when an arrest does not follow the offence, and hardly any police official will venture to claim that the arrest occurs in more than a moiety of the cases. There are hundreds of such crimes every year where the criminal is not detected, and hundreds of thousands of dollars worth of property stolen of which the police never find a trace."