A mob is usually a creature of very mysterious existence, particularly in a large city. Where it comes from, or whither it goes, few men can tell. Assembling and dispersing with equal suddenness, it is as difficult to follow to its various sources as the sea itself; nor does the parallel stop here, for the ocean is not more fickle and uncertain, more terrible when roused, more unreasonable or more cruel.

Barnaby Rudge: A Tale of the Riots of 'Eighty (ed. 1841)