It is in the dead of night, when London sleeps, that crime stalks abroad warily and plies its trade. The policeman passes on his beat, but the darkness hides the figures that creep along the streets or crouch behind high walls, and, defying bolts and bars, enter the houses of the rich—uninvited guests.

Having secured any valuables they can lay their hands on, they steal away stealthily to their lairs, and buy a paper the next day to read about the daring burglary which has been discovered by the early maidservant as she goes yawning down the stairs to light the kitchen fire.

The darkness of the night is the burglar's hour, for then he knows that the better parts of residential London are silent as the grave. And yet in the deadest hour of night a mighty crowd can be gathered as if by magic in a few minutes.

There is a red glow in the sky, the cry of "Fire!" rings out, and the engine rattles past with the thrilling shouts of the men, and instantly sleeping London wakes and pours a half-dressed crowd of men and women into the streets. A city of the dead becomes a city of wild, turbulent life in an instant.

There is no mystery of the City greater than that sudden gathering of vast crowds in the dead of night to see someone else's house on fire. In some areas the news spreads from street to street, even at such an hour, so rapidly that a huge mob is crowding every approach to the burning building before any of the fire-engines have been able to reach the scene.

In the neighbourhood of the great stations where the mail trains arrive between three and four o'clock in the morning, there is a sense of "life going on" that attracts a certain kind of loafer—a nondescript lounger totally different from the back-against-the-wall specimen of the daytime.

If some of those people who are attracted to centres of movement during the small hours could be tracked to their homes, we should be astonished to find that a good many of them are in respectable circumstances. They are generally men living alone, either bachelors or widowers, and some of them are professional men and the victims of insomnia.

There are men who get up constantly in the middle of the night and go out "to get rid of their thoughts," as one of the victims of this peculiar form of distraction once told me. These men haunt the streets in the dead of night; but they do not choose the lonely places, they want to see their fellow-men who are still awake and about, and the railway station with its bustle in the middle of the night has a peculiar attraction for them.

They wait about on the platform, most of them, as if they were going to meet friends; they watch the cabs away until the last luggage-laden four-wheeler has crawled out of the station, and then when the lights are turned down they go slowly out into the street again to make their own way home.

There is one phase of London at the dead of night which is remarkable, but it is not advisable to investigate it if you are alone. To see it you must spend an hour or two in "the streets with the open doors," and these streets are not to be recommended to the stranger between the hours of I and 4 a.m.