It is notorious that a mob will commit atrocities which a single individual could scarcely be tempted to perpetrate. The reason is partially evident from the statement just made. A more philosophical explanation may be given. It is a law of social intercourse that there is always among companies of individuals a more or less effective contagion of whatever sentiment is most powerful among them. Still further, this contagion or magnetic battery of sympathy, while pervading the whole assembly, likewise increases the individual potency of the sentiment in the mind of each person. It is for this reason, that an orator thrills more deeply each hearer in a vast sympathetic assembly, than he would the same individual in a less crowded company; that music is more inspiring in a great crowd of people than elsewhere, etc. In an assemblage where the finer sentiments are predominant, this contagion is of the finer sort, and serves to elevate the whole company: in a gathering where the lower passions preponderate, the contagion is of the debasing kind, and serves to excite still further the worst elements of brutality, and to sink the individuals which compose the company still lower in the scale of humanity. To the educators of the young and to the governors of the people, this law is of immense importance.
A mob is, therefore, not only under the influence of its worst passions, but every hour of its existence these are growing more potent, in the mob as an entity, and in the persons which compose it. The only true mercy which can be shown to such an assembly, aside from any question of the safety of community, is to suppress it; to suppress it at once; and to use every means necessary to that end. Relentless rigor is the only measure adequate to the occasion. It is the weakness of civilization that it hesitates to be cruelly kind. The mistake of the military authorities in regard to the New York riot, was lenity. The prompt and vigorous bombardment, in the beginning of the rising, of a block of the houses in which the rioters were safely ensconced, while covertly firing on the soldiers and policemen, would have done more to quell the mob than all subsequent proceedings, and would have saved life in the end. It would have forced the inhabitants of these houses who, as things were conducted, could safely give all possible aid to the insurgents, to compel these to lay down their arms, in order to insure the safety of the sympathizers. Had the first, and the second, and the third house from which the assassins were permitted to fire been battered to the ground with cannon shot, the last two days of fighting would have been unnecessary. The police cowed the mob wherever they met them, because they showed no quarter. They hit hard and they hit often. They felt that the way to knock the riot in the head, was to knock the rioters in the head. And they did it, as Inspector Carpenter says, 'beautifully.' New York feels as proud of these Metropolitan policemen as he does; and that is saying a great deal.