In most Continental cities a watchman takes his stand during the night on the topmost point of some high building, and gives notice by either blowing a horn, firing a gun, or ringing a bill. In Germany the quarter is indicated by holding out towards it a flag by day, and a lantern at night. It immediately suggests itself that a sentinel placed in the upper gallery of St. Paul's would have under his eye the whole Metropolis, and could make known instantly, by means of an electric wire, the position of a fire, to the head station at Watling-street, in the same manner as the Americans do in Boston. This plan is, however, open to the objection, that London is intersected by a sinuous river, which renders it difficult to tell on which bank the conflagration is raging. Nevertheless we imagine that the northern part of the town could be advantageously superintended from such a height, whilst the southern half might rest under the surveillance of one of the tall shot-towers on that bank of the Thames. The bridges themselves have long been posts of observation, from which a large portion of the river-side property is watched. Not long ago there was a pieman on Londonbridge, who eked ont a precarious existence by keeping a good look-out up and down the stream. Watling-street was chosen as the headquarters of the Fire Brigade for a double reason: it is very nearly the centre of the city, being close to the far-famed London Stone, and it is in the very midst of what may be termed, speaking igneously, the most dangerous part of the metropolis--the Manchester warehouses. As the Fire Brigade is only a portion of a vast commercial operation--Fire Insurance--its actions are regulated by strictly commercial considerations. Where the largest amount of _insured_ property lies, there its chief force is planted. It will, it is true, go any reasonable distance to put out a fire; but of course it pays most attention to property which its proprietors have guaranteed. The central station receives the greatest number of "calls;" but as a commander-in-chief does not turn out for a skirmish of outposts, so Mr. Braidwood keeps himself ready for affairs of a more serious nature. When the summons is at night--there are sometimes as many as half-a-dozen--the fireman on duty below apprizes the superintendent by means of a gutta percha speaking-tube, which comes up to his bedside. By the light of the ever-burning gas, he rapidly consults the "London Directory," and if the call should be to what is called "a greengrocer's street," or any of the small thoroughfares in bye-parts of the town, he leaves the matter to the foreman in whose district it is, and goes to sleep again. If, however, the fire should be in the city, or in any of the great West-End thoroughfares, he hurries off on the first engine. Five minutes is considered a fair time for an engine "to horse and away," but it is often done in three. Celerity in bringing up aid is