The problem before the policeman operating against a riotously disposed crowd is somewhat similar to that which confronts the soldier in the face of the enemy, and it was on this account that the Metropolitan force was given a semi-military organization. In some respects, however, the policeman's task is the more difficult of the two, chiefly because he has to strive for peace whilst actually engaged in conflict; the soldier at least enjoys the advantage of knowing his own comrades, whereas the constable is often unable to distinguish friends from foes, and continually runs the risk of converting the former into the latter. Whilst the greatest possible latitude must be allowed to individual constables, the secret of success lies in mutual, not in independent action, and for mutual action to exist, there must be discipline and intelligent direction. When the use of force can no longer be delayed, the plan adopted by the officer in command should be easy of accomplishment, simple of comprehension, and its success should leave the law-breakers at a strategical disadvantage sufficiently obvious to convince them of the futility of further resistance. Nothing is so fatal as vacillation: partial success leads on a mob to the commission of fresh excesses, partial repression only aggravates it. It is far better to leave a crowd altogether alone, than to sustain even an apparent defeat. Force is no remedy unless it is unswervingly and unhesitatingly applied; and as it is comparatively immaterial in what direction repression is exercised so long as it is consistent and irresistible, it is usually good policy to divert the energies of the mob towards the line of least resistance. It is more efficacious, for example, to keep a crowd moving in some definite direction, than to dissipate the strength of the police in attempts to arrest ring-leaders, to seize banners or the like, which may degenerate into a series of disconnected single combats not uniformly favourable to authority. Any apparently uncalled-for attack may convey the impression of wanton outrage, and so tend to defeat the object in view, by increasing that state of irritation and excitement which it is the principal duty of the police to allay. Many branches of police science which to-day are in the common knowledge were unheard of and unsuspected during the first half of the nineteenth century. This is particularly the case with regard to that part of the constable's duty which has to do with the management of crowds: before 1830 there were only two methods of dealing with a riotous mob, the first was to leave it severely alone, and the second was to allow a regiment of cavalry to trample it into submission. No government worthy of the name is justified in adopting a policy of non-interference at a time when the lives and property of law-abiding citizens are in preventible jeopardy, and the disastrous consequences that may follow upon the employment of