There is Divisional Detective-Inspector Helden, who probably knows more of the ways of the waterside thieves than any man living. He is a linguist, as are many of his staff--a qualification much necessary in dealing with the cosmopolitan crews of ships plying to and from the Port of London. There is an inspector who has saved three lives--a fact none the less noteworthy in that he holds the quaint superstition that all the troubles of those people will accumulate on his own unfortunate head. There is a bronzed, brown-moustached station-sergeant who had been around the world before he was twelve, and who has had strange adventures in every quarter of the globe. There are men drawn from the Navy--and now serving again--the mercantile marine, and river craft. All have an intimate knowledge of that thirty-five mile stretch of river which passes through London from Teddington to Dartford Creek. They know every eddy, every trick and twist of the tide; they know on any given day what boats are on the river, be they barges or liners; and they know the men who work them. The force is under the control of Superintendent Mann, who has had a varied experience of many years, and has brought a ripe knowledge of men and organisation to his work. There are five stations--at Wapping, Waterloo Pier, Barnes, Blackwall, and Erith--with a complement of 240 men, fourteen launches and motor boats, as well as row-boats. The division possesses its own engineers and carpenters, and does its own building and repairs. Now-a-days, men are only drafted to the division after serving for a time in the ordinary land force, but the rule has only been in force of late years, and consequently most of the men have spent their whole police career on the river. A different thing this to land work. In the whole thirty-five miles there are only five "sections." These are patrolled by series of boats putting off at different hours. For eight hours they ply to and fro, keenly vigilant, courteous as their colleagues in the West End, as helpful and resourceful in an emergency as men of the Navy. Sometimes a barge gets adrift. It has to be boarded and towed to safe moorings. Some of these barges have valuable cargoes--tobacco, silk, and what not--and the incredible carelessness of the owners in not always providing a watchman presses hardly on the police, who may, perhaps, have to spend a whole night in looking after some single craft. There was a case in which a barge broke adrift with L20,000 worth of goods aboard. "Oh, that would have been all right," said the owner off-handedly, when told that it had been safely looked after. "It would have come to no harm." Not a word of thanks. And that attitude is a typical one.