From an article entitled "Bow Street Police Court" by William Drysdale.

A nice chapter of horrors I could give you about the police museum, to which the public are not admitted. New officers are taken there to become familiar with the playthings of burglars, so that they may not mistake a sectional jemmy for a pair of sugar tongs. The collection of halters would make a good beginning; for a halter is used for one ceremony only, and then it is hung up in the museum, duly labelled with the name of its victim. Or the ghastly death masks of some of the unfortunate gentlemen who have been operated upon by the halters. Or the bundle of blue rags and ragged edges of shoe that once comprised the clothing of an officer in Ireland who was blown up with a dynamite cartridge. Or the great assortment of knives and pistols, of every imaginable shape, every one with a history. Or the samples of rope ladders, safe breakers' wedges, and other tools, skeleton keys, and what not. Or even the letter written to the police by Jack the Ripper. Or the articles representing every stage in the conversion of a pewter mug into bad shillings. Some of the coins were so well made that I am sure the Queen would take her monthly wages in them without question.